Can jetliner pilots program departures when specific RNAV procedures do not exist? Can commercial pilots (e.g. 737 and 737 Max) program departures into their on-board GPS navigation system for the first portion of a flight that doesn't have specific RNAV procedures?

A Boeing 737 uses a Flight Management System (FMS, see this question for details: What's the difference between FMS and FMC?). This FMS takes inputs from multiple navigation sources/sensors, including inertial, radio, and GPS. One part of this system is the CDU (Control and Display Unit, actually there are two installed), which is one of the interfaces to the FMS:

(source, this is from a simulator, real one looks similar)

On the page in the image above, the departure runways and SIDs for EDDK are shown as an example. The pilots can select the departure procedure that was assigned to them by ATC. This assumes the flight is conducted under Instrument Flight Rules (IFR), but since you asked about commercial operations this will almost certainly be the case.

A departure procedure without any specific RNAV waypoints (e.g. fly runway heading, then radar vectors) will still be selectable in the CDU. An item VECTORS will be displayed on the LEGS page between the departure runway and the first enroute waypoint. Once ATC clears you direct to a waypoint, the CDU can be easily updated by moving this waypoint to the top.

It is also possible to manually enter waypoints into the LEGS page if a pilot chooses to do so. The 737 CDU allows creating pseudo waypoints e.g. by giving a reference waypoint, a distance in NM and a course. This way, a more accurate route can be shown on the Navigation Display (ND). However, when getting radar vectors from ATC it is more likely the pilots will fly using HDG SEL (Heading Select) rather than following waypoints programmed into the FMS using LNAV (Lateral Navigation).


Could robots take over pilots' jobs and fly planes - if they can, then how? As technology is advancing, could robots take over pilots' jobs? If so, how might they accomplish this?

It's already in the works.  Fully autonomous unmanned combat air vehicles are no less than 10 years away.  I'd say that the major airlines will follow in 10-15 years, most likely starting with the elimination of the First Officer with fully automated functions.  Similar systems will be introduced, and most likely before the airlines on corporate jets.

It will be fought tooth and nail by the pilot unions, but sooner or later the algorithms these AI pilots use will become increasingly sophisticated to the point that there will be another incident similar to that faced by US Airways 1549 where an AI is under control and makes a decision saving the crew and passengers where 97% of all human pilots who, when faced with an analogous situation, failed resulting in a catastrophic accident.  Thus public confidence will be bolstered in these systems and public opinion will sway in their favor - even demanding these systems will be on board.  All that's required at that point is flights operated by AI are 40% more efficient and 63% more likely to be on time without interruptions of service due to weather, crew fatigue, etc.  At that point the first experimental, totally unmanned commercial flights will happen, probably after the corporate jets lead the way.

Military wise a similar thing is bound to happen as ACM algorithms improve, making super maneuverable drones which are capable of defeating Red Flag instructor pilots 97% of the time and more and more years of confidence built on the AI systems both in peacetime exercises and in conflicts will finally eliminate the manned fighters and bombers.

Perhaps the last vestiges of manned flying will be in general aviation and remote bush flying for commercial reasons (the revenge of GA?), but even these will slowly be eliminated as AI controlled aircraft and infrastructure capable of allowing off field landings and takeoffs, even in the most remote or difficult places come online.


What happens when a helicopter loses an engine? It seems like at this point it would be game over, since the spinning rotor is the only thing keeping it in the air. Is there any way to land a helicopter in this condition without crashing?

Helicopters are able to do something called autorotation if all thrust is lost.

  In a helicopter, an autorotative descent is a power-off  maneuver in
  which the engine is disengaged from the main  rotor system and the
  rotor blades are driven solely by the  upward flow of air through the
  rotor. In other  words, the engine is no longer
  supplying power to the main  rotor.

(Look in particular at the direction of flight arrows. Remember there's a lift vector coming of the blades as well in both cases.)

Basically, the collective is decreased immediately when thrust is lost for whatever reason. This allows the airflow coming through the blades to push them around, like a reverse windmill in a way, keeping the blades spinning. This also generates lift, keeping the helicopter generating some lift (while descending of course).

  At the instant of engine failure, the main rotor blades are
  producing lift and thrust from their angle of attack (AOA)
  and velocity. By lowering the collective pitch, which must be
  done immediately in case of an engine failure, lift and drag
  are reduced, and the helicopter begins an immediate descent,
  thus producing an upward flow of air through the rotor
  system. This upward flow of air through the rotor provides
  sufficient thrust to maintain rotor rpm throughout the descent.
  Since the tail rotor is driven by the main rotor transmission
  during autorotation, heading control is maintained with the
  antitorque pedals as in normal flight.

Once the helicopter reaches ground, the pilot will pull up. Since the blades were spinning a bit faster than needed for a hover since he was flying forward the whole procedure, he simply pulls up and levels out carefully close to the ground until the helicopter touches down.

This being said, you have to be careful, since if you're flying to slow you can't pull it off.

  When landing from an autorotation, the only energy available
  to arrest the descent rate and ensure a soft landing is the
  kinetic energy stored in the rotor blades. Tip weights can
  greatly increase this stored energy. A greater amount of rotor
  energy is required to stop a helicopter with a high rate of
  descent than is required to stop a helicopter that is descending
  more slowly. Therefore, autorotative descents at very low or
  very high airspeeds are more critical than those performed
  at the minimum rate of descent airspeed.

This dangerous conditions are shown in a height-velocity diagram as is seen below, in this case apparently from an R44.

Here's a little video to get an idea of how it looks for the pilot:

Autorotation is often time critical and has to be done right as there's only one shot and as such is practised by pilots on a regular basis.

All extracts in this section are from "Helicopter Emergencies and Hazards" by the FAA, an excellent and very extensive publication on the topic.


How to adjust time of useful consciousness for pilots acclimatised to high altitudes? The time of useful consciousness (TUC) is the length of time an average pilot, breathing ambient-pressure air without supplemental oxygen, is capable of functioning usefully at a given altitude.  For instance, at FL180 (approximately 18 kilofeet AMSL), the TUC is 20-30 minutes for a steady ascent to this pressure altitude, or 10-15 minutes following a rapid or explosive decompression; at FL280 (~28 kft AMSL), TUC is 3-5 minutes for a gradual ascent (and half as long for a rapid/explosive decompression), and, at FL400 (~40 kft), TUC is only 15 to 20 seconds, even for a steady ascent (and a mere 7 to 10 seconds following a sudden decompression).1

However, healthy humans are capable of a very considerable degree of acclimatisation to high pressure altitudes (and resultant low partial pressures of oxygen); humans have demonstrated the ability to acclimatise to, and live and function indefinitely at, altitudes up to 19.5 kft, and long-term acclimatisation is thought to be possible up to at least 24-26 kft (although complete acclimatisation takes an increasingly long time - up to weeks to months in the upper reaches of this range - at very high altitudes).2  As extreme examples, a pilot living in La Rinconada (elevation 16.7 kft AMSL) could have an indefinite TUC as high up as FL180 (where, as mentioned above, the average pilot would be able to function without supplemental oxygen for at most half an hour), and someone just back from climbing Mount Everest sans oxygène supplémentaire could potentially be able to maintain an indefinite TUC up to at least FL220 or so (where an average pilot would have a TUC not exceeding ten minutes or so).

A high-altitude-acclimatised pilot would obviously have considerably longer TUCs for a given altitude than a sea-level pilot (even at altitudes where even a highly-acclimatised pilot cannot function indefinitely); how does a pilot acclimatised to high altitudes adjust the times in the standard TUC table to account for this?

1: Despite the 50% reduction in TUC following a rapid or explosive decompression, these, paradoxically, tend to be less dangerous (except in the rare cases where the decompression is sufficiently violent, or occurs from a sufficiently inconvenient part of the aircraft, to cause severe damage to aircraft structure and/or critical systems, or to physically suck one or more of the occupants from the aircraft), due to their violently obvious nature, than gradual decompressions (where the aircraft occupants can easily become incapacitated by hypoxia before they even realise that they have a pressurisation problem).

2: Beyond 24-26 kft AMSL (in what is aptly known as the Death Zone), long-term acclimatisation is mostly thought to be beyond the human body's capabilities; however, some degree of incomplete acclimatisation (allowing one to survive and usefully function at these altitudes without supplemental oxygen for considerably - sometimes very considerably - longer than an unacclimatised person would be capable of, although not indefinitely) is possible (which is how it's possible for a sufficiently-acclimatised person to climb Mount Everest without using any supplemental oxygen at all), and some scientists (from Bolivia, appropriately enough) dispute that there is an upper limit at all (or, at least, one below 29 kft AMSL).

The simple answer is "they don't". Training will dictate that at altitude, they need to be able to don masks within a few seconds, regardless of an individuals tolerance to altitude. The problem isn't that you have X seconds of full-cognition and then you pass-out, your brain function degrades during that period. It's best to get your mask on and oxygen flowing before doing anything else, and this is how pilots train.

Euphoria and a false sense of ability is a side-effect of altitude sickness/hypoxia. There are numerous videos out there showing altitude chamber tests where individuals are given simple tasks as the oxygen saturation decreases. These tasks can be as simple as those infant "put the shape in the hole" boxes, and it is surprising to see how well the people think they are doing versus how poorly they are actually performing. These two things combine for a very dangerous situation and you, as a pilot, need to recognize that this can happen and to mitigate that as quickly as possible, without trying to take into account your own tolerance (which can change day-to-day) for altitude.

Check this one out, this is a military pilot getting cards wrong, this is a stark demonstration of the effects. These symptoms happen in seconds. Watch how fast his cognition comes back when given oxygen.

Or this one which demonstrates euphoria and the inability to follow directions or perform basic actions.


What is the altitude of the nose vs tail in airplane flight? Suppose you have an airplane flying level on a long flight. Now suppose you place one altimeter sensor in the tail, and one in the nose. Suppose you record and store these values independently (perhaps take 10 readings per second.)

And then suppose you graph this data.

This is the graph i'm looking for. Has anyone ever seen data like this?

In other words, i'm looking for experimental data which has logged a comparison of the altitude of the nose, vs. the altitude of the tail, (several times per second) on a long flight.

The intent is to study how the pitch of the aircraft is constantly in flux -- e.g. by turbulence, wind speed changes, the curvature of the earth, and (of course) by the pilot's inputs themselves, etc.

Yes that data exists , it is recorded during flight test data gathering for full flight simulators. The transducers used are not two bars altimeters, but direct gravitational angle finders and gyro's for increased frequency response. Sample rate was 30 Hz in the olden days, now 100 Hz or higher.

A full set of measurements consists of correlated sets of

pitch, roll, yaw angle measurements from dedicated mounted transducers;
angle of attack and sideslip, dynamic and static pressure, magnetic course, and all other parameters recorded by the aircraft instruments;
stick and control surface positions from dedicated mounted transducers.

The aircraft data sets are sold for a lot of money, your best bet would be to try to get your hands on flight data measurements for an older type aircraft or a type that is not produced anymore.

Next time you fly, you could even measure this yourself by using the transducers in your mobile phone, which has acceleration, rotational velocity and angle transducers, plus a set of linear GPS co-ordinates.


Calculating CL and CD from Cp vs. x/c graph data? I need to calculate CL, CD, CM coefficients for NACA 0012 airfoil at angle of attack 6 degrees and Re=7.5e5, Mach=0.05. I used Xfoil for getting the CP distribution, Cp vs. x/c graph and Cp-x-y data. With Cp-x and Cp-y data points I tried to calculate CL and CD values with a matlab code with equations given below;

I integrate the CP-x, CP-y points which executed with XFoil respectively to getting Cx and Cy. I used trapz command in matlab to integrate these points. However at the end of my calculation matlab code was found that CL=1.1936e-04 and CD=0.7249. However at the graph screen of XFoil CL and CD was different.

I can not understand that if the problem was about my solution method or my matlab code? How can I get the  coefficients with Cp distribution?

You have done it correctly. Only mistake appears to be swapping the CL and CD value.
Being said that, for the info, this CD mearly is a numerical error due to ds being finite as invisvid flow drag is zero.


Can I get my IFR practical and oral examinations directly through the FAA if I can't find designated examiner? A friend  needs to go for instrument and commercial check rides and can't find designated examiner that is local.  Can she schedule one at the nearest FAA office?

In theory it's possible to contact the local FSDO and ask for a checkride with an FAA inspector, and it's free (see here, here, here). But personally I've never heard of anyone doing it and I can't even find anything on the FAA's website about it.

The FAA's statistics show that in 2016 there were 34,156 initial checkrides with DPEs but only 465 with FAA inspectors (two thirds of those were for ATP), so it's very unusual. That file also shows pass rates by DPE vs. inspector, by the way, and despite some online horror stories it looks like the pass rates were broadly similar.

FWIW, it's fairly common for candidates to travel/fly several hours to a DPE (see the FAA's locator tool), either because there isn't one available locally or because they want to use the 'right' one. I don't know what your friend considers "local" and how far away she's already looked, but she may want to just look further away. Of course flying somewhere adds some costs but if she's doing IR/CPL then it's probably a relatively minor cost compared to what's she already spent on training and it's another excuse to fly (if she needs one!).


How would an airfoil react if it was flown backwards? Out of curiosity what would happen?

Would pressure on both top and bottom flip? or stay the same or act as a normal wing with less lift?

I'd assume it would still take longer to travel over the top than the bottom. Then conservation of energy takes effect and produces lift due to pressure, just wondering what negative effects happen?

What would happen? Flow separation on the suction side, but it would still produce lift like a regular airfoil. The L/D ratio would be lousy, however.

Only at a small angle of attack range will the wing show attached flow on both sides: When the stagnation point is right at the tip of the trailing edge. This behaviour is similar to that of a flat plate and produces a rather limited range of useable lift coefficients and substantially more drag than when used properly. But still you get more suction on one and more pressure on the other side. The blunt rear edge will cause flow separation at all angles of attack and substantially increase pressure (or form) drag.

An airfoil with a blunt trailing edge has an advantage over a flat plate because it will perform acceptably over a slightly larger angle of attack range, but still this will be no comparison to the behaviour with the blunt side facing forward. Indeed, the front of an airfoil needs to be blunt to allow its use over a larger angle of attack range, while its rear end needs to be pointed to reduce the area over which the flow separates.

Now I feel I should drop a line or two about the cause of lift. Essentially, a wing creates lift by accelerating the air that flows around it downwards. The inclination of the airfoil will already be enough to cause this acceleration, regardless which side faces forward. The plot below shows how several airfoils perform over the first 180° angle of attack.

Lift coefficient over the first 180° angle of attack (picture source)


What is the moderate dihedral angle for a low wing airplane? An increase in dihedral results in a decrease of the total lift produced by the wings. I would like to know the moderate dihedral angle (in degrees) for a low wing airplane, especially the amature built kind( for instance the rv-3).

Also, is there a recommended angle of attack for such category of airplanes.

Please do not worry about the loss in lift. It is real, but so small that it can be neglected. A poor flap or aileron seal will cost you more in L/D than the dihedral ever will.

The loss is proportional to the difference of the cosine of the dihedral angle to unity. With 5° (which is on the upper end of typical values for low wing aircraft) this is just 0.38%.

The exact amount of dihedral depends a lot on details of the configuration:

Aspect ratio of the wing
Fuselage size relative to wing root chord
Wing sweep
Directional stability

In general, you need a good balance between $c_{l\beta}$ (dihedral effect) and $c_{n\beta}$ (weathervane effect).


What problems do you start run into when an aircraft is disproportionally long? For example, lets say we design a plane with the same lengh as the A340-600, but has the width of an embraer erj-140. Assuming everything works, what problems would we run into in regards to aerodynamics?

The question reminds me of the DC-8 Super 61. I always found its fuselage to be absurdly long (picture below, source).

Friction drag

First of all, your volume to surface ratio will suffer. A more slender fuselage will have proportionally more surface area for the same volume than a more stubby one. The first aerodynamic effect, thus, is a higher friction drag relative to fuselage capacity. Below a fineness ratio of five, increasing flow separation will unduly increase drag. Moving from an A340-style fuselage to something more slender, however, will not affect separation.

While volume would need to be held constant in case of airships, the goal for an airliner should be to maintain seating capacity, which can be assumed to be proportional to floor space (within limits - aisle height should not drop below 6 ft). Therefore, the figure of merit should be volume$^⅔$, and the growth in skin friction drag (and structural weight) should be less severe with increasing slenderness of the fuselage. Also, with a longer tail the tail surfaces can be made proportionally smaller, which reduces friction drag a bit, too.

The graph below is from S. Hoerner's Fluid Dynamic Drag, figure 24 of chapter 13, and actually valid for flying boat fuselages. It shows nicely how the drag coefficient grows with increasing fineness ratio; however, since the drag coefficient is based on frontal area, this is slightly misleading.

Hoerner's comments to this graph include an optimum based on volume$^⅔$:

  The optimum ratio with respect to drag on frontal area, seems to be in
  the vicinity of 5. Based on (volume)⅔, a minimum drag coefficient is
  obtained at l/"d" ≈ 9, corresponding to l/b ≈ 15 in the hull family
  tested

Maximum Cruise Speed

When being operated at speeds approaching Mach 1, the more slender fuselage will show a higher value of the drag divergence Mach number, so the second aerodynamic effect of a more slender aircraft is a slightly higher cruise speed, wing aerodynamics permitting.

Again, a graph from Hoerner's Fluid Dynamic Drag (figure 37 of chapter 15) as proof:

Pitch Damping

Third, since the fuselage length will determine the lever arm of the empennage, a more slender fuselage of the same capacity will exhibit a higher pitch damping relative to its static stability. Pitch damping depends on the square of the tail's lever arm while static stability grows only linearly. Note that the tail size needed for the same stability and pitch authority will change inversely to fuselage length, offsetting some of the increase in zero-lift drag of the longer fuselage.

Take-Off and Landing Speed

If the landing gear remains unchanged, a fourth effect could be a lower rotation angle on take-off and pitch attitude on landing in order to avoid a tail strike. This might result in higher take-off and landing speeds.

This answer would be much longer if aeroelastic and structural considerations would be included. I restricted it to aerodynamic factors as requested.


Is a forward slip considered a "normal maneuver" under 91.175(c)(1)? After an instrument approach in IMC, 91.175(c)(1) requires, among other things, that operations below the DH or MDA must allow for a "normal rate of descent using normal maneuvers."
Can someone point me to a regulation or a definition of what is a normal rate of descent and normal maneuvers under this regulation?
Specifically, my question is whether a forward slip is considered a normal maneuver for purposes of 91.175(c)(1)?

I can't find any specific definition of "normal maneuvers", probably because it varies a lot by aircraft type and situation. But I did find AC 120-29A - Criteria for Approval of Category I and Category II Weather Minima for Approach that gives some indication of what the FAA considers not normal (section 4.3.1.6):

Part 91, section 91.175 requires that approach procedures should be
based on use of “normal maneuvers” before and after passing DA(H) or
MDA(H). Normal maneuvers typically do not involve use of bank angles
greater than 30 degrees, pitch attitudes in excess of 25 degrees nose
up or 10 degrees nose down, or sink rates in excess of 1100 ft. per
minute below 500 ft. HAT while maneuvering to land within the
touchdown zone, during go-around, or during a rejected landing. During
a missed approach, pitch attitudes in excess of +30 degrees or bank
angles greater than 30 degrees would typically be considered
excessive.

But even if there is a specific definition of normal maneuvers out there somewhere, I think the context is important too. 91.175 is about instrument approaches, not general flying. So I think you have to ask if slipping to land is a normal maneuver during an instrument approach and I'd say no.
The entire point of an instrument approach is to get you to the runway safely and predictably, and there's a lot of emphasis on stable approaches. I can't think of any obvious reason why you'd need a forward slip if you've flown an approach successfully. You might be able to come up with some scenarios (circling to land? shooting an approach with an MDA of more than 2000' AGL?) however I'm not convinced that it's a normal technique in the specific context of instrument approaches.
If you look at what the FAA says about forward slips in the Airplane Flying Handbook Chapter 8 it strongly suggests that slips are for limited and unusual situations:

Intentional slips are especially useful in forced landings and in
situations where obstacles must be cleared during approaches to
confined areas. A slip can also be used as an emergency means of
rapidly reducing airspeed in situations where wing flaps are
inoperative or not installed.

I find it hard to see how those examples fit with executing an instrument approach. But that's just my opinion. If you happen to know a DPE it would be a great question to ask them.


What is the intent of 61.93(b)(1)? (b) Authorization to perform certain solo flights and cross-country flights. A student pilot must obtain an endorsement from an authorized instructor to make solo flights from the airport where the student pilot normally receives training to another location. A student pilot who receives this endorsement must comply with the requirements of this paragraph.
(1) Solo flights may be made to another airport that is within 25 nautical miles from the airport where the student pilot normally receives training

The student must be endorsed with something along the lines of:

I certify that (First name, MI, Last name) has received the required training of section 61.93(b)(1). I have determined that he/she is proficient to practice solo takeoffs and landings at (airport name). The takeoffs and landings at (airport name) are subject to the following conditions: (List any applicable conditions or limitations.)

Emphasis on the word TO, in (1). I interpret this as "You must be endorsed to fly solo TO another airport for takeoffs and landings." However, my instructor, and it would seem the majority of the instructors at my school interpret it as "You must be endorsed to fly solo AT another airport for takeoffs and landings." The FARs seem to imply my interpretation, and the recommended endorsement seems to imply the opposite (in fact the endorsement doesn't even mention the 25nm part except in title).
The situation it is used in most commonly is the towered-field TO/LDG practice. There is a towered field about 10 miles north of our airport where we all go to practice. However, the instructor is required to fly dual up there, solo the student, and fly dual back. Is this endorsement required in that case?

The intent of the regulation lies at the beginning, in 61,93(a):

  §61.93   Solo cross-country flight requirements.

  (a) General. (1) Except as provided in paragraph (b) of this section,
  a student pilot must meet the requirements of this section before—

  (i) Conducting a solo cross-country flight, or any flight greater than
  25 nautical miles from the airport from where the flight originated.

  (ii) Making a solo flight and landing at any location other than the
  airport of origination.

Training and an endorsement from an instructor is required before you fly cross-country or to another airport to land.  61.93(b) covers what the instructor must do with you before you can do anything specified in 61.93(a).

In the scenario that you describe you are not "Conducting a solo cross-country flight, or any flight greater than 25 nautical miles from the airport from where the flight originated" or "Making a solo flight and landing at any location other than the airport of origination" so subsection (b) does not need to be complied with at all.

The endorsement would only be needed if you were going to takeoff solo from your home airport, fly to the destination (which as you said is only 10 miles away), and land there since it is required by 61.93(a)(ii).


What causes a helicopter to autorotate farther? Which characteristics improve a helicopters ability to glide a farther distance in autorotation? Do these same characteristics reduce minimum decent speed in autorotation or is that affected differently? If so, how?

In general, regardless of the number of blades, the more blade inertia, relative to blade area, the better for autorotation safety because the inertia buys you more time to establish the autorotative glide before blade stall when power is removed, and more time to settle into a landing at the end of the glide.  The downside is more sluggish response to power application and maneuvering inputs on top of the added weight itself, so there are the usual tradeoffs.

The Robinson R22 started out with very low blade inertia for maneuverability (Robinson did not initially intend the R22 to be a trainer), but blade weight was increased later in production to make the aircraft more forgiving, to help with the blade-stall-following-power-loss accident rate.  In the earlier R22's you had under 2 seconds to lower collective pitch following a power loss before rotor RPM decayed enough to get blade stall, and if you weren't fast enough, that was it - you were trapped in a falling object (that's not as bad as it seems - if a car stops or swerves in front of you, you have a hell of a lot less than 2 seconds to react to avoid being killed, don't you).

In large helicopters or smaller machines with high inertia rotors like 2 blade Bell machines, you have oodles of time to establish the glide and settle after the flare.  A Huey can be lifted into a hover, held for a couple seconds, and settled on the ground just on rotor inertia alone.

You see a somewhat similar issue between regular airplanes and flying lawn chair ultralights.  When an engine quits on an ultralight, because the thing is big with lower mass, it slows down pretty fast and you have to aggressively shove the nose down right away to maintain flying speed compared to something like a Cessna 150. And a helicopter rotor is just an airplane going in a circle.


Does air traffic control identify a distress situation when an aircraft flies triangles in the sky? There is an account in a TSB Canada investigation report after a loss of radio and transponder:

The emergency procedure to be followed by a pilot to alert radar
stations when in distress and unable to establish radio contact is to
fly a left-hand triangular pattern twice with two-minute legs, resume
course and repeat the procedure at 20-minute intervals.

After the loss of radio, the transponder was switched to 7600 (signal not picked up by ATC). Shortly thereafter, the aircraft experienced a complete loss of electrical power. The pilot did the triangular maneuver.
This story took place in 1998: Is this signal still used today? and has the same meaning in all ICAO countries?

To my surprise, this does exist, at least in the UK. According to the Manual of Air Traffic Services:

  7 Emergency Triangle Procedure

  7.1 Pilots lost or uncertain of position and experiencing either transmitter or complete radio failure are advised, as a last resort, to carry out special procedures to indicate to controllers that they
  require assistance.

  7.2 The aircraft fly at least two triangular patterns, before resuming course, as follows:

  Table 1:

  7.3 If a triangular pattern is observed, controllers shall advise the D&D cell of the position and track and continue to plot the aircraft
  whilst it is within ATS surveillance system cover. Controllers should
  also be aware of the effect wind may have on the pilot’s ability to
  fly an accurate triangle.

I say "to my surprise" because there are well-established procedures for comms failure under IFR and under VFR. But having said that, it's possible that the triangle procedure is more useful in the UK (for example) than the US, where there are usually plenty of uncontrolled airports around and many pilots have no need to talk to ATC anyway. In the UK, with a much smaller airspace, fewer airports and more ATC control (at least, that's my understanding), it may be more critical to give even VFR aircraft a "last resort" to contact ATC.


Still using knots, nautical miles, inches of Hg. Is that impossible to switch to SI units? Why doesn't the aviation industry use SI units?.

I believe only a few countries use meters and other SI units in air transportation, including India and China (please correct if wrong).

Using kts and NM in navy -- built from the length of the 1' arc on a meridian -- simplified nautical mental arithmetic, and likely also helped at the beginning of aviation.

Current ICAO recommendations

In Annex 5 - Units of Measurement to be Used in Air and Ground Operations, ICAO allows 3 non-SI units (knot, foot, nautical mile) to be used...

  as alternative units because of their widespread use and to avoid
  potential safety problems which could result from the lack of
  international coordination concerning the termination of their use.

... but overall states in the same document that only SI units should be used, the same units for all members. Nevertheless the termination dates for alternative units have not been specified:

  It is intended that the use of the non-SI alternative units [...]
  will eventually be discontinued in accordance with individual unit
  termination dates established by the Council. Termination dates, when
  established, will be given in Chapter 4.

Case of vertical measurements / altitude

Vertical measurement in meters may be the more complex due to the existence of flight levels in feet, with the full system of vertical separation based on FL.

This topic was discussed in Using feet vs meters for altitude?. The current question is not a duplicate of the latter.

Other non-SI units

Other non-SI measurements seem more easy to remove:

Horizontal distances in feet and nautical miles may be expressed in meters, as already done for runway lengths. It is not as important as it was to mentally translate a latitude offset in NM.
Atmospheric pressure expressed in Hg column height may be expressed in Pascal. Many pressure instruments can be already calibrated both in inHg and hPa.
Speeds expressed in knots (sometime in statute miles per hour) may be expressed in km/h.

Question

Wouldn't it be useful (and safer) in the long term if we could remove most of the imperial units from new aircraft instrumentation, procedures, ATC, documentation and maps (at least for anything other than altitudes)

Just asking what is the current view from the air transport community itself.

For me metric or imperial is not the question, from my perspective the key is standardization. Having 2 different unit systems has only got drawbacks:

Customers: many airline's customers are living in a metric system, and they do not know what's is a mile or a feet. Is a matter of making flights more comfortable.
Cost reduction: units transformation is finally a cost. Engineer at manufacturers and airlines need to spend some time using a calculator to understand what is meant by other unit system. Maybe is only 30 minutes per month, but if we are talking about 2000 people, we are reaching a cost that is not adding value of 1000h per month. Finally this cost is somehow appearing in our airplane tickets.
Reduce human factor: we all are humans and exposed to errors. The less opportunity we have to make an error the best. Already there had been an issue with satellites with unit conversion. Reducing this difficulty is finally improving the safety of the air transport.
Increase competence in the sector: suppliers from, let's say, metric system have an slight competitive disadvantage when competing for a contract with imperial units. The more competition in airline services, airplane manufacturers suppliers, handling services the lower the price of our tickets.

Having 2 standards is a cost that is not producing any value and is actually a sector issue, moreover, a society issue. From my point of view the industry should try to move to a single standard. Metric or Imperial, I don't mind.

Next discussion will be which side of the road we should drive...


What is the difference between mist and fog? Fog is a form of a cloud and it is said clouds are visible moisture.  We all know that mist (baby rain) is also moisture so I am curious when will a METAR say BR (mist) or FG (fog)?

Quoting from the METAR decoder:

BR Mist (Foggy conditions with visibilities greater than 5/8 statute mile)

FG Fog (visibility 5/8 statute mile or less)

You may ask "Why 5/8th of a statute mile?"  That's because 5/8ths of a mile is 1,006 meters, or about 1 kilometer.


What is the smiley face sensor at the stern of the F-4 Phantom? The F-4 Phantom has an interesting collection of sensors at the extreme rear of the empennage. What are these sensors for? My daughter calls them them smiley sensors but I suspect that is not the proper technical term. Her guesses as to their real purpose:

Detect other airplanes.
Detect smiles.

Which one is it?

Your daughter is right as explained here:

  The 'bug-eyed' face of the parabrake door mounting the two
  rear-hemisphere radar warning antennas.

So they do detect other airplanes and probably the smiles of their pilots too as they are getting close to the phantom.


Can cellular towers be used to correct INS drift? At a high enough altitude a line-of-sight can be established with multiple cellular towers. Can such information be used to accurately correct INS drift (assuming GNSS is not available)?

No, for several reasons:

There is no receiver onboard (granted, this could be remedied easily)
Cells are very small, their antennas are directional privileging ground. Detection from an aircraft is difficult. For an aircraft in cruise, the distance is at least 10 km, only a large cells found in rural areas would be received. In populated area cell radius is much smaller.
Aircraft switch from a cell to the other, most of the time before being able to create a stable link. This may be a problem or not, depending on the distance measurement principle. If the principle is based on measuring radio trip time rather than azimuth, a synchronization with the cell controller is required.
On the other hand, if angles are used to determine distance, triangulation is not really accurate as the angles are small, less than 60° by design. In addition receiving antennas must be phased arrays (or rotating antennas) to determine the transmitter azimuth and elevation.

Last but not least, this would interfere with the cell network working. This reason is among the critical ones cell phones must be powered off while flying on a fast aircraft like an airliner. Cell phones on US aircraft are not prohibited by FAA but by FCC (its scope of interest is frequency protection, not aircraft safety). When a cellular network is available in flight, then there is a tiny cell in the cabin,connected by satellite link to the ground telephone network. Same for WiFi. There is no connection with a ground cellular network.


Why does Schiphol airport have such a long taxi way? I heard that from runway 18R-36L the taxi time is around 20 minutes, I heard that this runway was built and is used mainly to reduce noise pollution, but what reasons are there for the length of the taxi?

Firstly, I'd like to make clear that the particular reasons for the placement of the taxiway are not all publicly disclosed, and there are undoubtably multiple factors involved. After looking at the airport in Google Maps, I notice a couple things. (Excuse the large picture, explanation below!)

1) Physical & Geographical Limitations

There is a pre-existing highway in between the runway and the rest of the airport. The runway could not be placed closer to the airport in the current direction without either removing the highway, or bridging over the highway (as the taxiway does). The highway would be unlikely to ever be removed, due to the extreme cost of removing pre-existing infrastructure, nor would they like to bridge a runway over the highway. Runways require a fair amount of maintenance in comparison to taxiways, and including a bridge in the design of said runway would drastically increase the cost and complexity of maintenance.

Looking at the map, there is absolutely nowhere to place a runway of that length and bearing without drastically engineering a solution. Beyond that, there does not seem to be anywhere within the "block" of the main airport to create a runway of that size, regardless of bearing.

2) Noise Abatement

The fact that the runway is in a less dense area also means that aircraft on approach would cause less noise disturbance for the populated areas nearer the core of the airport. In fact, for the northern approach, there are not many developed areas - it is primarily open fields. Aircraft are only allowed to takeoff to the north, and land from the north, on this runway, to avoid overflying the populated areas to the south of it.

3) Other Potential Factors

The above reasoning we can be relatively certain about. However, there may be other contributing factors, such as ground quality. As there are rivers and streams nearby (including the one that the taxiway bridges), much of the ground may be more difficult to build on, and require more expansive foundations.

Conclusion

Regarding a taxi time of twenty minutes, there is certainly potential for a taxi of that length, but it is not due to distance. The distance is not anything extraordinary compared to many other "Hub" airports. The time is likely substantially increased by the fact that, if runway 18/36 is in use, they will likely be told to taxi around 18/36. The primary reasons for the creation of this runway, cited by the planning committee, were arrival/departure capacity and noise abatement.

While this is certainly not a very efficient system, it is certainly the only solution I can see to provide a runway of that size. There could be various improvements, but cost is the overarching factor.


Why aren't test planes remote controlled? There was a recent accident where SpaceShip2 broke apart in mid-flight, killing one and injuring another.

Given that we can remotely control drones from the other side of the world, why couldn't we do the same with this test airplane?

Considering that it's all launched locally, it would not even have the lag that drones have.

Taking a plane that is designed to be operated by humans and retrofitting a system for remote control would be a big task. They do it with old fighter jets for use as target drones. But a target drone's task is pretty simple; fly like a fighter jet until it gets shot down.

At the point where SpaceShipTwo is, a bunch of testing has already been done. This is supposed to show that the vehicle is safe enough to move on to piloted testing. But testing aircraft and spacecraft is a dangerous job and things happen.

Creating a remote control system for an spacecraft like SpaceShipTwo would be much more of an issue. First of all, there will most likely be physical changes required, whether this is to install hardware to manipulate controls, or just electronics to remotely operate the flight computers. These physical changes will be extra work and will affect the tests, since when the plane is actually operating, those things won't be in place. And if those remote control systems fail, you lose the aircraft. Sure, you don't lose pilots, but why lose a plane just because a remote control system (which won't be used on production) fails? Should you spend time and money developing a complicated remote control system, or developing the actual vehicle?

Also, many tests require the pilots to be on board. They are not just testing the systems, but how the pilots interface with them. Having real pilots actually flying the vehicle is the whole point of this phase of testing.

See this related question as well: Why do the engineers need to be on board during testing?


What information might go in the remarks section of an IFR flight plan? When filing an IFR flight plan, what information might go in the "Remarks" section?

The remarks field, also called ITEM 18 field on ICAO flightplans can take a lot of information that you as the pilot deem necessary for controllers or authorities to know about your IFR flight.
The list of possible items in an ICAO flightplan ITEM 18 field is available over at the Skybrary, but here are a few examples that are commonly used:

(c) “TYP/” followed by type(s) of aircraft, proceeded if necessary by number(s) of aircraft, if “ZZZZ” is inserted in Item 9
Example: TYP/2 DE HAVILLAND HERON. Up to 60 characters may be used.
(e) “ALTN/” followed by the name of alternate aerodrome(s) or bearing and distance to navaid/navigation point closest to alternate point, if “ZZZZ” is inserted in Item 16. Up to 100 characters may be used.
Example: ALTN/MEDIUM AIRPORT
(k) “OPR/” followed by name of the operator, if not obvious from the aircraft identification in Item 7.
Example: OPR/BIG COMPANY
(o) “RMK/” followed by any other, plain language, remarks when required by the appropriate ATS authority or deemed necessary. There is no limit in number of characters to be used.
Example:RMK/TRAINING ILS APPROACH AT SMALL AIRPORT
RMK/STUDENT SOLO FLIGHT


How does the power transfer unit in the A320 work? As far as i know the function of a PTU is to power one hydraulic system (either green or yellow) that is experiencing low pressure driven by pressure from the other system which still has the normal 3000 psi, where no fluid transfer happens. I have read (correct me if im wrong) that this happens with the help of hydraulic pumps, but how exactly does the "power" transfer happen?

The PTU consist of a hydraulic motor that drives a hydraulic pump.

The motor is driven by one hydraulic system, the shaft of the motor is connected to the pump and the pump powers the other hydraulic system.


Why is one of Madera Municipal's runways labelled with only "R" on both sides? I was looking on Google Maps satellite view and noticed Madera Municipal Airport in Madera, CA (ICAO KMAE) has an east-west runway labelled with nothing but the letter "R" on both sides. There is no parallel runway. Why the strange marking? Airnav reports it as runway 8/26, so why not label it that?

Composite for both ends via Google Earth

R is for Restricted. From the chart supplement (formerly AF/D) that runway (8-26) is restricted for agricultural use only.

It's non-standard, both internationally (ICAO) and on the FAA level for Part 139 airports (see AC 150/5340-1M). Note that the airport is neither international nor Part 139, so standards may not apply.

(via skyvector.com)

Beyond the meaning of the non-standard R, the Madera County's website offers this (PDF; Sep 2015):

  Future abandonment of Runway 8/26 when the agricultural aerial applicator lease expires in 2019.

This hints at a legal agreement with a local agricultural operation. Perhaps someone who is familiar with the local government there can offer more insight.


Please provide some expert commentary to the aborted flight of the German chancellor This week the German chancellor's plane (an Airbus A340-300) had to abort the flight due to loss of communications. The newspaper write they only had a satellite phone left1:

  Die Kommunikationssysteme waren ausgefallen, sodass kein Kontakt zum Boden möglich war. [Der Pilot] musste deshalb per Satellitentelefon mit dem Flughafen Köln/Bonn die ungeplante Landung vorbereiten.

  The communication systems failed, contacting the ground wasn't possible.  The satellite phone had to be used to prepare the landing.

  Man gehe derzeit von einem Fehler in einer elektronischen Verteilerbox aus, die sowohl die Funkanlage als auch das System zum Ablassen des Kerosins steuere, hieß es von der Luftwaffe.

  Currently an error in a distribution box is most likely.  The box services the radio as well as the fuel dumping system.

Is the antenna for the satellite uplink an integral part of the air plane?  As suggested here for WiFi.  I assume satellite phone doesn't work from inside the plane without an external antenna, is this correct?

Maybe this is nitpicking, but when the satellite phone is build into the airplane, with the necessary tracking, why is this not considered part of the communications system?

How come that seemingly crucial yet quite simple two way radio can fail and is not powered by some very basic passive turbine?  How much power is approximately required by the radio?

Satellite phones would be for passenger use.  Over land, ATC uses VHF/UHF radio, and over sea, ATC uses HF radio or (text-based) satellite data links.

Based solely on the quotes in the question, it sounds like a power distribution panel in the aircraft failed, leaving them with no radios.  There are procedures for aircraft with failed radios to continue flight, but it's a lot of extra work for both the flight crew and ATC.  And who knows what other equipment on the same power panel was affected.

Having a satellite phone available means the crew may be able to contact ATC and arrange a diversion and landing faster and more easily than the usual no-radio (NORDO) procedures allow, but neither ATC nor the crew would want to operate that way for any longer than necessary to land safely.

Also, specific to a Head of State, the protection detail would want to reassure their comrades on the ground that the aircraft hasn't been attacked or hijacked, and they would also prefer any problems be repaired at home by people they've already vetted to reduce the risk of espionage or sabotage.


Why are different routes flown between the the same pair of airports? On two of my trips (same airline, same kind of plane 777), I noticed that the airplane took very different routes (from New York to UAE).

1st Trip in 2012 (blue): Duration 11h 30m

2nd Trip in 2013 (green): Duration 13h 00m

I know that the blue line is the shorter distance, and probably also because of jet streams, it took lesser time. But why a plane would take this green route, even not considering jet streams?

Since I am not an important person, I could not ask the captain of the plane this question at the end of journey.

P.S.: I observed the flight paths on the entertainment system this airline has for all passengers.

Lots of reasons are possible, ranging from winds to other issues. In this case I'm willing to bet that the first flight was based on the most efficient routing to take advantage of tailwinds en route and that the second was avoiding Syrian and Turkish air space because of the political issues there earlier this year.

See also:

Flight Delays Incurred Avoiding Syrian Airspace
Royal Jordanian stops flying over Syrian airspace


Does the center of lift have to be in line with the center of mass? Imagine 2 theoretical planes, A and B, shown in the image below. The center of mass is yellow, and the center of lift is blue. Would plane A and plane B work as well as an airplane with the center of lift in line with the center of mass or no?

In my opinion the vertical position of the center of gravity (CG) is negligible.
First of all the variation will be very small. Between an airplane with lead on the bottom of the cargo and an airplane with all passengers on the upper deck the CG will not move that much. And statistically the CG will probably be somewhat around the centerline of the fuselage.
Then, yes drag forces and engine thrust could create a tiny pitching moment but the leverage will only be a few inches at max thus the moment being very small compared to the gravity VS lift pitching moment resulting from the horizontal distance between CG and CP.
In the end question is somewhat similar to :
"what's better low or high wing planes?". On one side CG is above or near the wings and on the other hand way below the wing. Both works fine and requires only small design variations for aerodynamics stability.


How does flying with flaps differ from flying with airbrakes? I've got a private pilot license and learned on a Scheibe Falke SF25. For the last year however I've only been flying a C42 Ultralight.

I find flying the UL way easier for one particular reason: it has flaps where the Falke has just airbrakes.

I don't know how many hundred landings on the Falke I have done, still I have never felt comfortable. The reason is the airbrake. For some reason it scares me. With the UL I set the speed, lower the flaps and if I'm too far away I can add a little power. The flaps lower the stall speed and make the plane slower.

The airbrakes also make the plane slower, however they increase the stall speed. I see how (especially flight instructors) pull the air brake to the maximum and then do their approach. If I'm too far away with the Falke, I have to retract the air brakes. This affects the plane very directly, especially compared to adding a little power on the UL.

My questions are:

How to correctly land a plane with airbrakes? Full out or just a bit? Do you leave them in one position or do you vary during approach?
How much do they really affect stall speed?

The SF-25 has such a low wing loading that it easily tolerates the small reduction in maximum lift which the airbrakes cause. I have done very few flights in it (I'm too tall to fit comfortably in it's cramped cockpit), but from what I remember the airbrakes are not very big, having little effect on minimum speed. My experience, however, is with the SF-25 B, and you linked to the SF-25 C, so I have to assume that my experience is not fully relevant.

I have more experience with real gliders and composite motorgliders, and here my experience is: Start your approach, stabilize the right approach speed, set the airbrakes such that your glide path looks right and do not play around with them too much. Set your approach such that you need medium airbrake extension, so you have margin for corrections in both directions. Normally, I come in a little high so I am not caught by windshear, and when I am sure I will reach the intended touchdown point, I extend the airbrakes fully to land with the shortest distance possible. However, when touching down, make sure you do not fully extend the airbrakes: This gives you more time for stopping the descent. Especially in gliders with very effective flaps and airbrakes (ASW-20 C, ASH-25) I never made a good landing with fully extended airbrakes. Reduce them to half extension at the most when touching down!

In the ASW gliders the airbrakes are linked to the very effective wheel brake, and touching down with fully deployed airbrakes means that the wheel is braked at touchdown. This is another reason to reduce airbrake extension when touching down.

In high-performance gliders it is easy to float too long, so it is very important to control your approach speed and to continue the descent all the way down to the touchdown point. Don't pull too early! The SF-25 will not float as much, but with its low wing it shows a pronounced ground effect, and exercising strict discipline when landing helps a lot to make the landing better.

I could not find a number for the stall speed change due to airbrakes in the SF-25 manual, but I would guess it is at most a few km/h.


Who can request a check on an engine before boarding/takeoff? I have read on a newspage that a passenger found an engine problem on the B767 before takeoff and requested staff to check it, while the airport claims the decision was made by the pilot.

I was wondering: Who has the right to do such decision. Will the engineers check the engine just because of a passenger's complaint?

I guess this will vary from airport and scenarios. Say if you are in a small Cessna on a little grass-strip: They will most likely always listen to you. However, In a passenger jet, on a busy airport: Things fast get a little more complicated. It is very expensive for an airliner to hold a plane, and even more to ground it. And it affects more people than it would with the Cessna scenario.

If you tell, say the flight attendant while the plane is rolling down the taxiway that you hear abnormal sounds: They will likely misinterpret you as nervous and will most likely ignore it. But if you can somehow socially convince them: It is still the captain that makes the end decision about turning around.

I don't know if this has actually happened before other than in the article mentioned in the question.

If there is something wrong about the plane: The captain will likely know well before you do. The engines have so many sensors and fail-safes that the captain will likely have the fault displayed in the cockpit before you even notice something unusual, and he will probably make the decision before you even reach a flight attendant.


What is the purpose of the plush-like seat covers in an airliner cockpit? What is the purpose of the plush-like seat covers that I have seen on almost all the airliners I looked at? See for example the following picture of a Bombardier CRJ flight deck:

(wikimedia.org)

Check out this related question

And this forum topic.

They help prevent wear and tear on the seat fabric underneath and are fairly easy to replace. In a lot of GA planes they are installed to hide old tired seats underneath. But mostly they are just really really comfortable. They breathe in warm weather and help insulate in cold. All around a good fabric choice for the application (see related question for notes on fire prevention).


Why are combi airliners no longer being built? Why are combi airliners no longer being built?  Is the reason structural, economic or regulatory?

While combi configurations are rare, they do have a place -- for instance, when operating narrowbodies into remote locations which have a demand for cargo that exceeds what can be put in the belly, but also need pax transport.

The most recent combi configuration I can find a source for is the 2008 work done by Aviation Traders to configure Iron Maiden's touring plane.  In this case, they used the existing seat rails to mount pallet fittings in order to avoid structural changes to the floor, and also are taking special steps (such as firebagging of cargo) to mitigate against a main deck cargo compartment fire.

As to why they aren't made otherwise?  It clearly isn't operating economics, at least for Alaska Airlines, Canadian North, First Air, and other current combi operators -- otherwise they'd have retired their combis by now.  The main issue, I strongly suspect, is actually the unsolved problem of fire suppression in large, main deck class B cargo compartments, such as those found on combi aircraft.  Aviation Traders' work on Class F is intended to solve this problem, made famous by the crash of SAA 295 after its main deck class B bay experienced a fire of unknown origin that proved catastrophic.


What are the drug testing procedures for EU airlines? How do EU airlines test aircrew for drug use, specifically marijuana? Do they use hair tests, and how far back in time can they detect marijuana use?

I am not a pilot but you may find the following useful:
Civil Aviation Authority, INFORMATION NOTICE, Number: IN–2015/012

5 Drug and Alcohol Screening Programme
5.1 The  testing  process.
Trained  staff  should  carry  out  screening  tests  usually  by  mouth  swab,  breath,  blood,  hair   or  urine  sample.  Tests  are  becoming  simpler  to  administer  and  less  invasive  as  the  technology  continues  to  improve.  Minimal  notice  should  be  given  of  the  intention  to  undertake  random  testing.  The  sample  collection  and  testing  process  should  be  designed  to  ensure  the  result  is  reliable.  If  a  positive  result  is  found  further  (usually  blood)  testing should be undertaken. A confirmed positive result should be reported to the relevant Civil Aviation Authority regulatory authority; in the UK the report should be sent to the Medical Department of  UK CAA  for aviation licence holders.

It is easy to find companies whose business is testing UK pilots for drugs, for example AlphaBioLabs:

Protecting the aviation industry with drug and alcohol testing
We specialise in providing drug and alcohol testing to the aviation industry for both individuals who want to show that they are drug or alcohol-free and companies as part of their drug and alcohol testing policy.
Our aviation industry workplace testing consists of the following:

Random drug and alcohol testing
Pre-employment drug and alcohol screening
For-cause drug and alcohol screening
Post-incident drug and alcohol testing
Abstinence monitoring

We have a team of fully trained sample collectors in your area, ready to collect your drug and/or alcohol samples from your place of work or any safe environment.

...

Hair drug testing
Hair drug testing is a form of workplace drug testing that can be used to support other methods such as oral fluid and urine testing.
It can be particularly useful for a more comprehensive overview of a person’s drug use as it is known as a ‘wide-window’ form of testing, which can determine a history of drug intake for up to 12 months.

A different lab reports

British Airways, for example, tests urine for drugs and breath for alcohol. Workers can be randomly tested in the first six months of employment or if returning to work after rehabilitation, and can also be tested if it is suspected that drugs or alcohol may have caused an accident, or if they are suspected of being under the influence while working.

Relevant incidents might include things like this:

Air Astana, which is part-owned by UK firm BAE Systems, said it fired the pilot immediately and had a zero tolerance policy for drugs and alcohol.
In a statement to Reuters it said: “The airline regularly tests its crews for alcohol and drugs using a random sampling method."


What are different components of an engine pylon? What are the different structural components that are inside the fairing of engine pylon and what are the functions of each part?
The pylons for each aircraft are made of Ti-64 alloys, can they be made using Aluminium alloys or the temperature requirements are very high so Aluminium cannot be used?
Thanks

Your question is very broad.  Are you looking for something specific? There isn't really a single configuration where one can simply list standard function of each component, but  I can give broad overview.
Firstly, pylon is also a conduit for multiple systems between aircraft and engine and thus contains secondary structure for mounting them. It looks much like aircraft wing with frames and ribs to support distributed loads. Secondary structure is easily made from aluminum and includes brackets, cleats, supports, stand-offs, and attachment hardware like clamps, nuts, bolts. Also pylon skins/fairings can (depending on design) be minor part of load distribution. But I presume you mean primary structure components that are most directly associated with mounting  the engine.
The functions are to attach/support engine (including withstanding emergency/crash/FBO loads), transmit thrust to airframe, and accommodate engine thermal expansion. Most generically, this is achieved by structural members forming a torque box or space frame. But realization and component names vary a lot. The are two fundamental families depending on attachment: 1) fuselage (i.e.) side-mounted,  and 2) wing (i.e. vertically)-mounted. We won't go into exotics like above-wing & wing-root mounting. Furthermore, there are few styles of wing-mounting (with different components) that fundamentally are driven by relative location of engine to the wing and relative size of engine to aircraft. There are also different mounting philosophies like soft-mounted (with elastomeric vibration isolators) or hard-mounted (without such).
Bear in mind that aircraft structures are designed to distribute load across multiple members and provide redundant load paths, so as to intentionally avoid single point of failure. Having said that,  4 key  elements can be identified:

a forward mounting beam/strut, which is perpendicular to engine axis and usually terminates in a yoke/frame that wraps around engine fan case. It primarily supports engine weight, but also crash loads & lateral FBO loads, including subsequent windmilling.
a thrust strut/link/mount, which is most aligned with engine thrust line, but inevitably runs diagonally to connect engine to pylon structure. It carries most of the thrust load into airframe, but would also carry longitudinal crash loads.
An aft/rear mounting beam/strut, which is also perpendicular to engine axis. Depending on engine size & proportion, in can vary from a frame to yoke to very thin struts. Aft mount's (primary but not only) function is to provide 2nd support point to secure the engine and allow expansion.
Space frame further into the body that disperses the loads and provides rigidity out of principal plane created by elements 1-3.

In a fuse-mounted configuration the principal plane is horizontal and functions are more decoupled. In wing-mounted configurations the principal plane is vertical and some functions & load distributions are more coupled.  Other designs like B-747, where engine hangs far below wing attachment points, rely on a space fame of axial members to suspend the engine in a 3D truss (as can be seen in previous post with link to FAA accident investigation). The functions mentioned before are even more coupled & shared between all members. The names are really irrelevant as Boeing chooses to refer to them as upper/ lower links and side braces.

In terms of actual parts, this is realized by main fittings, sleeves, bushings, alignment pins, load-bearing pins/bolts, etc.
Materials: Actually aluminum is widely used in mounts, with steel as required, and titanium when $/kg weight trade studies justify it. Titanium is expensive & horrendously difficult to machine and is used sparingly, albeit more so on recent designs that push margins. Of course, as everything in such highly complex products, it depends on specifics and sizing of a given design. Temperature must be considered, but is typically not a driving factor, especially for fuselage- mounted  engines,  and areas adjacent to cold sections of the engine. Actually it works out quite well - the heaviest and most loaded section of engine (like fan)is in front, which is cold. The loads are best supported & reacted by a big, intricate mount with large x-section area & moment of inertia (like yoke). Manufacturing it from titanium would be cost prohibitive and it is best made from aluminum. The aft hot section of the engine is supported by simpler, smaller struts that could be made from titanium. For wing-mounted though, the whole pylon area is subject to heat soaking, but weight is more evenly distributed between forward and aft mounts, so having smaller, simpler titanium fittings is practical.


Are there two types of runway holding position sign? I came across this section on runway holding position marking while reading Jeppesen Airway Manual, which got me very confused.

My question is: Is Pattern B describing another type of runway holding position sign other than the one described in Pattern A? Or is it just describing the ILS critical area boundary marking for CAT II & III approaches? I'm asking this question because I've never heard in my whole aviation career that there are "two" runway holding position markings, nor seen one.

I’ve never seen the critical area hold bars referred to as a type of runway hold bars, but they serve the same general purpose when the critical area needs to be protected, so I can understand the point of describing them together.


Which speed shall be used on high speed taxiway? After landing, which speed shall we use to exit from high speed taxiway? Max. 60 knots ground speed or indicated air speed?

According to the ICAO manual on Aerodrome Standards (based on Annex 14) (link) - maximum 35 knots for code 1 and 2 runways, and maximum 50 knots for code 3 and 4 runways.

Since you are moving on the ground, it makes sense to use your ground speed as reference.

I imagine most aircraft operators have procedures for using rapid exit taxiways in their standard operating manuals. As a result, the actual speed used by air crews is likely to vary depending on which company they fly for.

IFALPA recommends that you slow down to normal taxi speed on the runway, and then use rapid exit taxiways with normal taxi speed (as opposed to the very low speed you would need to use to turn off the runway using a pendicular taxiway). (link)

From the ICAO manual:

  3.8.15

  A rapid exit taxiway shall be designed with a radius of turn-off curve of at least:

  550 m where the code number is 3 or 4; and
  275 m where the code number is 1 or 2;

  to enable exit speeds under wet conditions of:

  93 km/h where the code number is 3 or 4; and
  65 km/h where the code number is 1 or 2.

Note: you can find the definitions of the code numbers (1, 2, 3, 4) on page 17 of the manual to which I linked above.


Why does spin recovery involve cutting the throttle? When recovering from a spin, the first step is generally to cut the throttle:

  ... Otherwise, to recover from an upright spin, the following generic procedure may be used: Power is first reduced to idle and the ailerons are neutralized. Then, full opposite rudder (that is, against the yaw) is added and held to counteract the spin rotation, and the elevator control is moved briskly forward to reduce the angle of attack below the critical angle. Depending on the airplane and type of spin, the elevator action could be a minimal input before rotation ceases, or in other cases the pilot may have to move the elevator control to its full forward position to effect recovery from the upright spin. Once the rotation has stopped, the rudder must be neutralized and the airplane returned to level flight. This procedure is sometimes called PARE, for Power idle, Ailerons neutral, Rudder opposite the spin and held, and Elevator through neutral. ...  [Wikipedia]

This is extremely counterintuitive; given that another vital step in spin recovery is to apply full down elevator1 to get the nose down, one would expect that the blowback from the engine (especially for tractor-propeller aircraft) would aid in recovery by striking the underside2 of the deflected elevator, and, thereby, pushing the tail up (and the nose down), making it seem, at first glance, that it would be best to firewall the throttle in order to get the tail up and the nose down as quickly as possible.

In addition, even without the contribution from the elevator, applying full throttle would:

drag the aircraft forwards through the air, increasing the forward component of its motion and decreasing the angle of attack seen by all the various parts of the aircraft;
for tractor-propeller aircraft, blow air at high speed backwards over the wings, dramatically lowering the local angle of attack felt by the wings.

Both of these effects would tend to destall the aircraft and transform the spin into a boring old trivial-to-recover-from spiral dive.

So why do spin-recovery procedures for most aircraft generally call for cutting the throttle, rather than firewalling it?

1: Or, if spinning while inverted, full up elevator.

2: Replace "underside" with "upper side" if spinning inverted.

Applying engine power can indeed help to end a spin. But the added thrust will make an overspeed in the ensuing spin recovery much more likely. Also, applying asymmetric thrust on the wrong side will flatten and stabilize a spin. These are the main reasons why the engine should be idle in spin recoveries.
Remember the Boeing 307? The first passenger airliner with a pressurized cabin and the civilian version of the B-17. It was test-flown by KLM personell on March 18, 1939. It entered a spin after a stall and the rudder became stuck in spin direction. The pilot applied asymmetric power in order to stop the yawing motion and succeeded in doing so, but in the subsequent recovery the aircraft oversped and the outer wings broke off. Here is the official accident report.

Boeing 307 in flight (picture source). Note the small fixed vertical surface which was replaced after the crash with a much bigger one.
Symmetrical thrust can be helpful or adverse for spin recovery, depending on circumstances. NASA TN D-6575 from December 1971 says that

no systematic study of the effects of applying power during a spin

is known and

The effect of applying symmetrical power in a spin is believed to be insignificant. A number of varied observations have been made through the years by many people, and the conclusions regarding power effects on spins range from favorable to adverse. […] In almost all cases, the results were not obtained under controlled conditions. Therefore, the type of spin, the center of gravity, the angle of attack, the spin rate, and the line of thrust with respect to the center of gravity were not identified.

Therefore, a general recommendation for applying symmetric thrust for spin recovery cannot be made and only asymmetric thrust has shown to be helpful if applied correctly:

the application of thrust had no effect unless the thrust axis was displaced from the center of gravity and thereby produced a moment.
[…]
For asymmetric power for a twin-engine configuration with the engines mounted on the wings, power from only one engine can produce a large asymmetric yawing moment, which will be favorable or adverse to the spin and recovery, depending on the direction of the moment. Both model and full-scale spin-test results of multiengine airplane designs have shown that power on the outboard engine (e.g., the right engine in a left
spin) can create a large prospin yawing moment, which can cause a flatter and faster spin. On the other hand, power on the inboard engine can create an antispin moment to aid spin recovery. Normally, the manipulation of thrust can be confusing and disastrous if the power is applied to the wrong engine. Therefore, unless asymmetric power is necessary to aid recovery, it is generally recommended that for a multiengine airplane, the throttle be retarded to the idle position on all engines during a spin.

It should also be mentioned that the extreme angle of attack at the inboard engine will produce an extreme sideways displacement of the thrust vector on a propeller or uneven flow in a jet intake. In both cases such a flow condition was most likely not anticipated during design and could result in the loss of the propeller rsp. a compressor stall in the jet engine if full thrust is applied.
While I do not know of a propeller having been lost in a spin, during the flight test of the Dornier 328 an extreme sideslip did indeed overload the left propeller, parts of which tore a massive hole into the fuselage.


Does the APU consume a lot of fuel compared to a jet engine? I would like to know whether the APU of modern commercial airliners consumes more or less fuel than a jet engine. Of course, this will vary between aircraft types, so what comparisons in fuel usage are there on a modern jet such as a B737 or A320? What is the ratio between an engine hourly fuel consumption and the APU hourly consumption?

To give a comparison with an engine at idle:

On the 737 NG, the APU can use 240 lb/hr when under load. It is rated at 90 kVA, same as the generator on each engine.

The engines can use about 850 lb/hr at idle, which from those figures is about 1/10 of fuel flow at full (takeoff) power. So the engines use about 4 times as much fuel (each) as the APU does to just provide power. Of course these values will vary based on ambient conditions and the load placed on the systems (like the bleed air system).

This is why if a plane has to stop away from the gate for a while, they will shut down the engines and run on the APU.


Do U.S. aircraft carriers still include a Marine Corps squadron? When I was in the 3rd Marine Air Wing back in the early 70s, there was one Marine Corps squadron on each navy aircraft carrier, but on some shows I've seen recently (mostly on the Smithsonian Channel) I haven't noticed any Marine Corp aircraft. This leads me to wonder if they're stilled deployed on the carriers.Edit: I found this picture in the 2018 Marine Aviation Plan
Notice the "VMFA-251" marking on the fuselage. This would make it a Marine Corps aircraft. Just above the picture is this blurb:

  The F/A‐18A‐D community continues combat operations for the sixteenth straight year as Hornets support Operation INHERENT RESOLVE: Landbased with SPMAGTF‐CR and shipboard on aircraft carrier deployments as part of our TACAIR Integration (TAI) commitment.

This certainly implies that some Marine Corps aircraft are deployed on some aircraft carriers, but not necessarily all of them.

According to Wikipedia's page on Carrier Air Wings, there are nine active carrier air wings currently active (for eleven aircraft carriers).  Of those nine, CVW-9 includes Marine Corps squadron VMFA-314 operating the F-35C Lightning II, and CVW-17 includes VMFA-323, which operates the F/A-18C Hornet.
So out of nine carrier air wings, two include Marine Corps squadrons.  Not all carrier air wings include Marine Corps squadrons.  I believe other Marine Corps squadrons train on aircraft carriers, but are not permanently associated with air wings like VMFA-312 and VMFA-323 are.


How do fighter pilots manage food, drink & toilet? There doesn't seem to be any place to bring food or drink.
And what about WC?

And for single seat combat planes?

Life Strapped to the Rocket

Food and Drink

Fighter pilots do not have any problem taking food and drinks on flights.  The biggest concern is to prevent foreign object damage (FOD) from items like crumbs, bottles, bags, etc.  Otherwise, there are plenty of places to carry food to eat: your helmet bag, G-Suit pockets and flight suit pockets.  I typically carry water with me in my g-suit pocket, and don't worry about food unless its going to be a long flight.  Thankfully, training missions are rarely long enough that they require food in the cockpit, and it mostly just applies to deployments.  Typical food usually includes protein bars, chocolate, cereal bars, etc.  We try to avoid small loose foods like peanuts and M&M's because they could easily spill and FOD the cockpit.

Depending on cockpit altitude, the mask can be easily removed to either eat or drink.  However, fighter cockpits are only partially pressurized, and, in the Super Hornet, there are times when cockpit altitude can be as high as 20,000ft.  Sound judgement is required before removing your mask.

Edit: I've also seen guys incorporate camelpacks into their harness/vests as well.

Restroom

Obviously life on board a fighter jet is cramped, and there isn't a lot of room to move your body, much less use the restroom.  In addition to water, on every flight I carry an item called a pittle pack.  As its been stated, its a plastic bag with powder in it that reacts to urine.  The powder and urine mixture then turns to a jelly that helps prevent spillage, and the entire bag then rolls down and seals on itself.

Pittle packs present 2 major problems (three for carrier pilots):

First: Where the hell do I put this bag of urine? There isn't a lot of storage space on fighter aircraft and nobody wants to put a bag of urine in their g-suit pocket or helmet bag.  Sometimes you can get away with placing the bags in the flight publication pockets, but you better be sure it doesn't fall out.  The last thing you want is for the bag to fall, break, and then to smear about the cockpit as you continue with your mission.

Second: How do I get my junk out of this rocket powered chastity belt? My harness is strapped tightly 8 ways to the ejection seat, which is also cinched tightly to my g-suit.  My g-suit has an opening for my crotch, but its tightly zipped into position over my flight suit.  My flight suit has a zipper, but as stated, the zipper is covered by the g-suit.  And just to add one last layer of difficultly to this impenetrable force field, I've got to dig myself out from between the folds of my boxer briefs.  Success! I've managed to free myself only to discover that the tip of my business end is only barely protruding from this labyrinth of zippers and belts (size may not matter in the bedroom, but it sure as hell matters right now).  The next question you have to ask yourself is, do I have enough time to keep digging, or do I need to attempt to arc it into the bag?  Choose wisely.

Third (The carrier pilot):  Boom, OK three-wire trap!  Ah , the Naval Aviator.  I drop bombs, piss in bags, and then return home to land on a boat.  I'm pretty much a boss... and I'm covered in piss because I didn't secure my pittle pack before trapping on the boat.  The bag, upon catching the three-wire, like a boss, rocketed across the cockpit and smashed against the bulkhead, exploding all over my legs.  Always remember to secure your pittle packs before trapping on the boat, because even if your buddies didn't see it happen, you can guarantee the ground crew will tell them all about it.

Our female counterparts are forced to wear depends, I don't envy them at all.  Brave souls.

Oh, and if its not pee, RIP.


Why did the propellers not fail to the feathered position in the Atlantic Southeast Airlines Flight 2311 Crash? In the ASA Flight 2311 crash the failure of a quill resulted in the loss of propeller pitch control.  The propellers ended up with a pitch angle of 3 degrees which caused reduced thrust and increased drag resulting in severe asymmetrical thrust situation.  The airplane was uncontrollable in this configuration and crashed. The propeller manufacturer, Hamilton Standard, had tested the propellers in a laboratory and had shown that the propellers will feather with a loss of pitch control.  However, a flight test orchestrated by the NTSB had shown that due to the "aerodynamic forces of flight" the propellers did not feather as designed.

My question is what exactly caused the propellers to not feather in flight when the propellers successfully feathered in the laboratory?  I am looking for a more detailed answer than "aerodynamic forces of flight".

You can find the full text of the NTSB investigation here and according to that report (bolded for emphasis),

  Examinations of the left propeller components indicated a propeller
  blade angle of about 3 degrees at impact. This position was based upon
  the position of the pitchlock acme screw. The left PCU ballscrew
  position indicated that the PCU had commanded a blade angle of 79.2
  degrees. The discrepancy between the ballscrew position and the
  position of the pitchlock acme screw is a strong indication that a
  disconnect between these two components occurred prior to impact and
  that the left propeller had achieved an uncommanded blade angle below
  the normal flight range.

And later in the report

  Using measurements and the inspection procedures for the quill and
  transfer tube of the Hamilton Standard Alert Service Bulletin, it was
  determined that the left PCU quill spline was worn to the extent that
  its gear teeth did not engage the transfer tube spline. In addition,
  the test cell and flight tests showed that the propeller blade angle
  could not be controlled by the PCU with a disengaged transfer tube. In
  the test cell, the blade angle moved toward high pitch; however, the
  propeller was operating at zero airspeed and did not experience normal
  flight loads. In contrast, the flight tests showed that the blade
  angle would move toward low pitch with a disengaged transfer tube. The
  blade characteristics indicate that centrifugal and aerodynamic
  twisting moments tend to move the blades toward low pitch.

  The Safety
  Board believes that the worn quill on the left engine PCU became
  disengaged from the transfer tube prior to the loss of control of the
  airplane during the approach to Brunswick. Moreover, the propeller
  blades moved to a low angle, resulting in an asymmetric lift and drag
  condition that exceeded the capability of the pilots to counteract
  with the airplane controls available.

In simple terms the unit that controls the propellor pitch experienced a failure from worn out components that lead to a case where the propellor did not completely feather. The specific part seems to be the PCU quill (to answer your question directly).

Even later in the report they discuss why the failure was not really covered by the testing originally. The testing was not necessarily incorrect as much as it may have been incomplete and not foreseen this issue with the quill.

  The investigation found that wear of the quill was not considered
  during the certification of the propeller system because of the very
  light torque loading on the quill during flight. Service history of
  the PCU quill prior to the introduction of the titanium-nitrided
  transfer tube indicted that quill spline wear was not a problem.
  Additionally, the manufacturer provided an analysis during
  certification indicating that even in the event of a failure, the
  propeller would either drift into the feathered position or maintain
  the blade angle present when the failure occurred. However, the
  accident involving flight 2311 and the subsequent investigation
  have determined that these assumptions, though originally supported by
  numerous engineering evaluations and manufacturing experience, are
  invalid and that there are single failure modes that could result in
  an uncommanded propeller blade angles below flight idle.


Where to find information on ILS categories at European airports? I have a list of airports in Europe and I need to find up-to-date information about ILS categories (I, II, IIIa, IIIb or IIIc) at these airports. Does anyone know where I could find such data efficiently?

The information you are after is, unfortunately, rather distributed.

Eurocontrol maintains a useful list of websites ordered by state, found here:

European AIS

Or by registering for an EAD Basic account you can access the European AIS Database in a more centralised and user friendly way, found here:

European AIS Database


How can I switch off the yaw damper in an Airbus A350? How can I switch off the yaw damper in an Airbus A350?
In the A320, this can be done by switching off the FAC, but the A350 doesn't have a FAC switch; it has prim and sec instead of FAC and ELAC.

On the simulator normally you can simulate the failure of the yaw damper actuators which has the same effect as switching off the yaw damper.
On the aircraft you can’t do it from the cockpit panels without switching off lot of other functions


"Turn right, report heading"? I can't say anything about authenticity, but here is a quote

Tower: “Delta Zulu Romeo, turn right now and report your heading.”
Pilot: “Wilco. 341, 342, 343, 344, 345…”

Is such an instruction even allowed? And if so, what should the pilot's response be?

The title of the website (Aviation Humor) should give you a hint. It is a joke!
However, there are a few similar situations, one of which is a pilot requesting a turn to avoid weather. That could go something like this:

Pilot: ABC123 request right turn to avoid

ATC: ABC123 right turn approved, report new heading

Pilot: Approved, WILCO, ABC123

Pilot: ABC123 now heading 120

Though normally, the pilot will give a rough estimate of how much they need to turn ("Request right turn 20 degrees to avoid").
Another example is ATC giving a pilot a relative heading change, and asking the pilot to report the actual heading.

ATC: ABC123 turn right by 10 degrees, report new heading

Pilot: Right by 10 degrees, heading 250, ABC123

The reason ATC doesn't just give the target heading to the pilot directly is that in many cases ATC does not know the heading of a flight - only the track. In cases with strong wind especially, the heading and track may differ significantly.
ATC can also tell a pilot to turn without giving a target heading, during non-gyro operations (compass gyro inoperative, so pilot does not know his heading). But in that case, the pilot will not respond (so you won't be hearing "341, 342, 343..."). ATC will then time the turn, knowing that a standard turn is 3 degrees per second.

ATC: ABC123 make all turns rate 1, start and stop all turns on the word NOW.

ATC: ABC123 turn left NOW.

(wait for a specific number of seconds)

ATC: ABC123 stop turn NOW.


What are those things at the wing tip of an aerobatic aircraft? See:

The radially placed needle-like things that resemble a snowflake in the first picture.
The triangular structure in the second picture.
In the third picture, the object placed on only one wing
In the last one, it's also placed on one wing but this one is perpendicular.

What are those things?

They are external attitude references. They're aligned with the aircraft's axes and positioned along the pilot's line of sight to give a quick visual guide to the aircraft's attitude during aerobatic maneuvres.

You can see the alignment more clearly on this photograph


In what manner was the Vympel R-73 (AA-11 Archer) a game-changer in comparison with NATO's missiles? I have heard that when the Vympel R-73 air-to-air missile was introduced it was a game-changer.

I have also heard that after the collapse of the Soviet block it was tested by NATO (via re-united Germany) and NATO was quite impressed by it. According to one source, in close combat the MiG-29 was better than the F-16 by 2:1 and better than the F/A-18 by 1.5:1.

What was so special about it? How did they make it? Did they have better experiences? Or ideas?

The Russians brought some new ideas to the missile warfare when they mated the Vympel R-73 with Mig-29. The most important of these was the high offset sensor lock mode, which allowed the pilot to 'lock on' to the targer regardless of where the nose was pointed at. According to Peter “Stoini” Steiniger a JG 73 Pilot, who flew Mig-29s in East Germany,

The nice airframe in combination with one weapon was the killer: The Archer in [sensor lock] mode.” Introduced in the mid-1980s, the Archer AA-11 is a very capable heat-seeker with a greater range than the U.S. Sidewinder. “A simple monocular lens in front of my right eye enabled me to slew the seeker head of the missile onto my adversary at high angle off [target].” The Fulcrum’s ability to lock a missile even though its nose was pointed far away from its target “watered many eyes,” ...

The image below shows the missile aiming sight mounted on the helmet of a JG 73 pilot.

Image from airspacemag.com
This off boresignt advantage was not achieved by the western forces till they introduced the AIM-9X missile and the Joint Helmet-mounted Cueing System in 2002.
Aircraft-wise, the Mig-29 was a revelation to the west as the previous Russian designs have not been so sophisticated, so as to speak. The West was concerned enough with Mig-29 to start looking for new fighter ideas. Another important equipment in Mig-29 was the Infra Red Search and Track System (IRSTS), an idea for which the US is just warming up. Most of the exchange pilots, who flew the Mig-29 against the US F-15s and 16s were quite surprised and initial engagements usually went the 29s way, though techniques were later devloped exploting the Mig-29s' weaknesses. From an USAF exchange pilot:

From BVR (beyond visual range), the MiG-29 is totally outclassed by western fighters. Lack of situation awareness and the short range of the AA-10A missile compared to the AMRAAM means the NATO fighter is going to have to be having a really bad day for the Fulcrum pilot to be successful.
In the WVR (within visual range) arena, a skilled MiG-29 pilot can give an [F-15] Eagle or [F-16] Viper driver all he/she wants.


How can I find my grandmother's OLD instrument rating documentation? This is my grandmother, Nathalie Myrtle Brown:

The big-eared kid she's posing with is my dad.

She has a claim to fame in that she was the first female instrument-rated pilot in the state of Iowa, a fact that figures prominently in her obituary

  In the 1960s [...] Nathalie and Walt took flying lessons and became licensed pilots. Natalie, the first woman pilot in the state of Iowa to hold an instrument rating, enjoyed flying their planes back and forth between Iowa and Colorado.

I distinctly remember, though, my mother telling me that Nana was the first female instrument-rated pilot west of the Mississippi River.

That memory is the only basis I have for thinking the achievement might have been more than 'first in Iowa'. Unfortunately, Mom died a few years ago and no one else in the family remembers anything bigger than the state of Iowa for the claim.

So, I'm curious. How can I read her pilot certifications from the 60s, possibly earlier?

The sub-question here has been answered to my satisfaction. The "west of the Mississippi" memory is nothing.

next day: I found a newspaper clipping from The Carroll Daily Times Herald, 19 June 1965, showing that she landed in Carroll, Iowa that week. Apparently all landings at the Carroll airfield made the paper. Amusing.

Here's an undated photo from the website of my cousin, Maribeth:

Perhaps there's a clue in the picture to date the plane? I have no idea which came first, the Piper Cherokee or the Cessna. @reirab points out in comments that people without an aviation background often call small planes Cessnas and the fact that Cessna is misspelled on the picture certainly supports the idea that it was done by someone without said aviation background. This could be the Piper Cherokee?

The FAA has an airmen inquiry search portal. I put Nathalie Brown and came up with Nathalie Myrtle Brown with the following details:

Certificate: PRIVATE PILOT   Date of Issue: 11/25/1968
Ratings: PRIVATE PILOT
AIRPLANE SINGLE ENGINE LAND
AIRPLANE MULTIENGINE LAND
INSTRUMENT AIRPLANE

As @FredLarson points out in comments the date supplied seems to be the last change to their database, i.e. address, name or addition of rating, so that means she must have gotten all of her certificates at or before the 25th of November, 1968.
This is a start, but it doesn't give you real dates. If the FAA has that much information they should have a lot more, to get details you should contact the airmen certification branch. I'm not sure what hoops you have to go through, maybe prove you are family, etc.
There is a big database of pilots from the FAA search portal, but it is not complete - your grandmother wasn't in it for example, and there's no dates of ratings anyway. Maybe the FAA can get you access to a better airman database with more of those records, it's possible they simply don't exist anymore though, you'd have to ask.
If she has personal effects left then her pilots certificate or other details may be there, certificates used to be paper, probably folded up. Really useful would be her logbook, which would be a record of every flight she made, there would be endorsements in these which would be useful in learning when she achieved her ratings.


How does a fighter “thump” an intercepted aircraft? In P&E Never Again: A Thump on Final, commercial pilot Mike Mercer describes an encounter with an F–16 shortly before rounding out to land.

  Without warning, the Baron abruptly yawed 15 degrees right, and there was a thunderous noise on the right side of the aircraft. I was standing on the rudder pedals to maintain directional control and managed to keep things more or less aimed at the runway … On the rollout I got a look at the F–16 in full afterburner climbing back to altitude and turning to circle the field. I concluded immediately that we had been “thumped,” a procedure we used in the military that was designed to rattle and harass the pilot of an intercepted aircraft.

For context according to the linked account, this incident took place inside a VIP TFR that the author flew into unwittingly. His hand plotting and ADS-B display on his EFB led him to believe the TFRs were well north of his destination. Shortly after departure, the author attempted to request but was unable to obtain flight following.

What maneuver does an intercepting fighter perform to “thump” its target? Other than the severe yaw that the author mentioned, what are other typical aerodynamic effects?

'Thumping' is an (unofficial) term for maneuvering the aircraft so that the other (target) aircraft is caught up in its wake. As a practice, it seems quite widespread, atleast during cold war scenarios, and is explained elsewhere:

  Aircrews call it “thumping” — the aviator’s version of a baseball hurler’s brushback pitch. A fighter jet zooms up behind a lumbering reconnaissance craft, then blows past with afterburners blazing, pulling up and away just in front of the larger plane so its jet wash disrupts the airflow around it.

The effect is the same as flying into other aircraft's wake turblence, though the effects may not linger as long as the aircraft passes quite fast (that being the idea- to harass, rather than to cause an accident).

That said, I doubt it was done deliberately in this case as it is quite dangerous to both the aircraft and intercept procedures are quite clearly defined.

Intercept procedure; from FAA media release

Note that it specifically states to be cautious of wake turbulence. Maybe the author got caught in the wake turbulence of the fighter accidentally and it brought back memories of his service days.


Why are longer wings with foldable wingtips used on the B777X instead of lighter ones with original size? The new Boeing 777X has longer wings to improve efficiency, but has to adopt foldable wingtips to "fit" into all original airports that host its predecessor.
Tendentially, longer wings would have an higher weight and foldable mechanism surely add extra weight too, but thanks to new materials, new wings should be almost as heavy as previous ones.
For me, in absence of further information and comparisons, it's not so easy to understand why this solution is surely better of simply have lighter wings with original length, that would allow benefits too.

This explanation is given here :

The wing of the 777X is based upon the design of the 787’s wing. It
has less of the sweep of the 787 but 10% more surface area (increased
from 4,702 to 5,562 sq. ft.). The re-shaping has led to a higher
lift-to-drag ratio, which(and) in turn increases usable fuel bulk from
320,863 to 350,410 lb. As a result, the type will have a range of over
14,000 kilometers (8,699 miles).
Boeing’s motivation for its including folding wingtips within the
design was not wholly steered by fuel economy. With a fully-extended
wingspan of 71.8 meters, the new 777X falls within the ICAO’s
aerodrome Code F. But with raked and folded wings (and a span of 64.8
meters) the type can comfortably arrive at gates designed for Code E.
Aircraft in this group includes the current 777.

So not only are they looking for more surface area and aerodynamic efficiency, they need to house more fuel to give it an extended range.