texts: How should flaps be used during an emergency landing (PPL)?

texts:
I'm still doing my PPL, but one question has puzzled me recently. During an internal exam before my first solo nav on a C150, the examiner pulled the throttle, so I would do a simulated emergency landing. I chose a field right to me, and with a good gliding speed and without any flaps did a 180 turn (base+final) and found myself flying straight into power lines before the field. We had to go around.

The examiner showed me how it should be done. After the base turn, he deployed flaps 10 and then on final 20. We flew way above the power lines. Now I'm not sure all the altitudes and turning points were the same, but he meant this to show me that I should have used flaps.

My understanding had always been that the use of flaps during emergency landing should be restricted to the final leg from the point that you are certain you will make the airfield. My instructor (not the examiner) had the same view and could not explain it to me.

Any idea?


texts: Which en-route services are available to UK GA pilots?

texts:
I have recently taken up flying again in the UK, and although very little has changed in the 10 years I have been inactive, the one area which seems to have changed is in the en-route services available to pilots.

It used to be the case that you could request a Flight Information Service (FIS) and a Radar advisory (RA) service - I seem to recall there being one other which I never used, which I cannot quite remember the name of.

I believe the FIS is now referred to as a "Basic" service, is this assumption correct? Does it vary in any material way from the defunct FIS?

What other services are available to GA pilots in uncontrolled airspace? Where do I find the details of stations and what service(s) they provide?


texts: Who is responsible for avoiding collisions on the ground; the pilot or the air traffic controller?

texts:
I may have some false assumptions here, so correct if needed. It is said that while ATC sounds like they are "in charge" of the airspace surrounding a major airport, control and responsibility for any given airliner is (still) in the hands of the Pilot-In-Command (PIC).

What this means is that if an airliner is given instructions to do something by ATC, and they are unable (or unwilling) to follow those instructions, they are able to tell ATC they are unable and ATC has to work it out, with all of the ramifications that implies. If the ATC controller wishes, they require the crew to contact ATC by other means (the dreaded phone call, I suppose) to explain, but the fact of the matter is, the passengers are ultimatley depending on the crew to keep them safe.

Now, let's take an airliner, at the gate, readying itself for a flight. They receive a pushback and are ready to taxi. They contact ATC Ground for instructions. Ground gives them taxi instructions. Who is responsible for the safety of the aircraft at that point?

Why do I ask this, when it should be obvious, the PIC. However, visibility out of the aircraft is limited, especially in some of the larger craft. As far as I know, there is no "check the mirrors" or "objects in the rear view window may be larger than they appear." The PIC simply CANNOT see behind the aircraft, and so any ground vehicles, personnel, or other aircraft (small or large) could cause an accident, which would be out of the control of the PIC.


texts: What classification of aerial vehicle would a manned quadcopter or octocopter be?

texts:
US here, if it makes a difference (w.r.t. FAA regulation, etc.).
There's a new upcoming class of aerial vehicles, similar to drones, however they are gigantic and they are manned -- that is, manned (piloted) quadcopters or octocopters like these ones.
I'm wondering what technical and/or legal classification(s) these types of vehicles would be considered to be. Any thoughts? Thanks in advance!


texts: In modern aircraft is lift only generated by wings or can other parts of fuselage generate a significant amount as well, to the point it needs to be accounted for when designing a plane?


texts: Do fuel tank locations on the wing cause a potential for weight imbalance?

texts: I have a question about fuel tanks in an older plane like a P-36C Hawk and a P-26B-35. The fuel tanks in the P-26 are placed in the wings and in the P-36C Hawk its under the pilot and behind him. For the P-26 or any plane with its fuel tanks on the wings would it cause more weight on one side if the fuel is used more then the other?


texts: Why is there a pressure drop in the combustion section of a jet engine?

texts:
This image, referenced in this question, shows in green the pressure value in a jet engine:

The combustion section between compressor and turbine is where fuel is injected, mixed with air, and burnt. Why is there a pressure drop while combustion occurs and temperature suddenly increases by 1,500°C (to be compared with pressure increase after ignition in a reciprocating engine).


texts: If an A/C have Radio failure ( sqk 7600 ) How the ATC will give him instruction or how will he land?

texts:
If an A/C have Radio failure ( sqk 7600 )
How the ATC will give him instruction or how will he land ?!


texts: Is this scaling of aircraft size and power (at least roughly...) correct?

texts:
I use to fly a very light plane, with a 100-hp engine. In order to calculate the power needed by a similar plane, but 50% larger, I reason as follows:

In general, the power required by an airplane is proportional to its weight times its speed. The weight scales with the cube of the linear dimension, so the larger plane would weigh 1.5 cubed = 3.375 times more. Since the airspeed is squared in the formula for lift, the exponent for the proportionality of lift should be 1/2.

I have now two exponents for the scaling, 3 for the weight (or mass, in this case) and 1/2 for the speed. As the weight and speed are multiplied in order to get the proportionality of the power required, I add the exponents, and the result is that the larger plane would need an engine of 1.5 ^ 3.5 = 4.13 x 100 = 413 hp.

Is this OK?


texts: Could the experience of inflatable structures in boats be applied to large aircraft design?

texts:
Inflatable structures in boats have proved extremely successful and versatile since they began to find widespread use in the 1930s.

I'm aware that experiments have been made with inflatable wings - very light, delicate structures mainly on human-powered and unmanned aerial vehicles.

On boats, they're used differently: in some cases they form the main structure of the craft itself, in some, the craft has a rigid hull and the rest of the structure is inflatable, but either way, the inflatable sections are very far from delicate.

Experience gained with multiple air cells in inflatable engineering means that it's now possible to build effectively rigid structures, that are extremely tough, reliable and resilient. Their behaviour in failure modes is well-known.

Many large aircraft have built-in air compressors - the engines - that could keep the inflatable structures correctly pressured at all stages of a flight.

Materials science has produced enormous improvements in the longevity and resistance to chemicals/sunlight/temperature ranges of the rubber skins of inflatable structures.

What opportunities are there for designing parts of an aircraft as inflatable structures (perhaps winglets, or undercarriage doors)?

Is there any research or experimentation into more heavy-duty use of inflatable engineering in aircraft?


texts: How is Kool-Aid used as a visual cue to create contrast for an off-airport landing?

texts:
In part 7-5-13 of the AIM, there is quite peculiar guidance given:

  g.  Off-Airport Landings.

  In the event of an off-airport landing, pilots have used a number of different visual cues to gain reference.  Use  whatever  you  must  to  create  the contrast you need. Natural references seem to work best (trees, rocks, snow ribs, etc.)

  (a) Over flight.

  (b) Use of markers.

  (c) Weighted flags.

  (d) Smoke bombs.

  (e) Any colored rags.

  (f) Dye markers.

  (g) Kool-aid.

  (h) Trees or tree branches.

How exactly is Kool-Aid going to assist in an off-airport landing?


texts: Who else is using electro-thermal wing anti-/de-icing apart from the 787?

texts:
I am researching into deicing technologies for the future, but apart from Boeing with Ultra/GKN, no one seems to be picking this technology up and being competitive. Any one know why this is? Is it an expensive development? Risky?

Is it on any aircraft manufacturer's roadmaps?


texts: Is there any Class G airspace south of Portage Bay in Seattle?

texts:
I would like to apply for a waiver to fly a UAS to take pictures over the campus at Seattle Pacific University that is located just south of Portage Bay in Seattle but I'm told that can only be done in Class G airspace.  Is there any Class G airspace in that area?  Thanks.
Alan Rither


texts: How to accurately determine Navigation Accuracy from FAA's PBN Criteria (Order 8260.58A)?

texts:
I am trying to understand how to determine the Navigation Accuracy for a given flight phase of an Instrument Flight Procedure, from the US Standard for PBN Instrument Procedure Design (Order 8260.58A). However, I am unable to understand how to determine the aforementioned accuracy under certain circumstances, given that, for example in case of A-RNP navigational specification and STAR flight phase, it states that:

  1-2-4.c, Table 1-2-1 A-RNP permits a range of scalable RNP lateral navigation accuracies. Apply the largest RNP for the flight phase unless a smaller value is required to achieve a desired ground track or is operationally required. RNP APCH applies to final flight phase.

My question is, in other words, why a desired ground track would require a smaller navigation accuracy value? Under what circumstances such a ground track would be desirable and, since the goal is to provide an adequate Obstacle Clearance Area, doesn't this mean that smaller accuracy value would lead to a smaller obstacle clearance area?

It is a really technical question and I do not expect to be a popular one, but I would really appreciate if someone could point me in the right direction.


texts: Other aircraft doesn't apply right of way rules

texts:
I was flying VFR a couple of days ago and was warned by ATC that another aircraft was coming from my left to my right.

At some point I saw it and we were clearly converging and getting pretty close.
According to the right of way rules I had priority, but the other aircraft didn't change its heading (maybe the other pilot didn't see me - he/she didn't seem to be in contact with ATC).

According to the rules I was supposed to keep flying the same heading and altitude but I decided to turn left to avoid her and it worked fine - however I can see how it could have been dangerous had the other aircraft changed its heading at the same time.

So I'm now wondering:

What is the "right thing" to do when another aircraft doesn't follow the right of way rules?


texts: How do I contact Flight Service while in flight?

texts: How do I contact a Flight Service Station (FSS) in the United States in order to receive weather information or open a flight plan after I've already departed.


texts: Do helicopters use more fuel when hovering?

texts:
This answer says

  A helicopter uses a LOT more fuel hovering than it does in forward flight.

Is this correct? Why?


texts: Should I have carb heat on for landing in a C152?

texts:
There is quite a debate about this! I'm a student, have gone solo. My first instructor insists the carb heat goes off/COLD on the approach ('ready for go-around' if needs must! And to prevent dirty unfiltered air entering on landing). My second instructor goes along with the POH and insists the carb heat stays on/HOT until landed (saying icing is more dangerous than dirt).

I LIKE the idea of keeping the carb heat on because if a go-around is needed all I have to do is remember to push in the throttle AND carb heat (and retract flaps, 30 to 20 degrees,etc.) no matter what height. I learn that ONE move. But if I'm trained to take carb heat off, say at 300', and learn only 'throttle/flaps' for go-around, I'm worried I'll FORGET carb heat's HOT if I do a go-around from 400'! See what I mean?

What's the best method for a student to learn?


texts: The crash of the concorde resulted in many deaths, but the crash was never caused by the concorde but by a plane that took off before it. Also airliners like the Boeing 737,747,and 777 have had accidents resulting in all deaths of the passengers and crew and was caused by the airplane, but are still in service today, so why are those airplanes still in service after the accidents and the concorde not in service after its accident that wasn't even caused by the concorde?


texts: Why do carburetors tend to produce richer mixture at higher altitude?

texts:
The pressure drop in the venturi is proportional to air density and the fuel is at ambient pressure in the float chamber, so I would expect the fuel flow to reduce proportionally with density, and that response to preserve the fuel-air ratio over changing altitude.

But in practice that does not seem to be the case. Proper response to altitude requires additional modification that most carburetors don't have, so the pilot usually has to lean out the engine as they climb. What am I missing here?

(Update) More specifically, I would expect that at the same RPM, the volume flow rate will be the same—because the engine pulls in its displacement per revolution. Now velocity in the venturi $v$ is just

$$ v = \frac{\dot V}{A} $$

Where $\dot V$ is the volume flow rate and $A$ is the cross-section of the venturi. So it will also be the same independent of altitude. Since dynamic pressure

$$ p_d = \frac 1 2 \rho v^2 $$

And that is also the pressure that pulls in the fuel (when the float chamber is open to ambient pressure). Substituting mass flow

$$ \dot m = \rho v $$
$$ p_d = \dot m \frac 1 2 v $$

and as long as $v$ is mostly constant,

$$ p_d \sim \dot m $$

This still leaves open the dependence of fuel flow on $p_d$. If the relation is reasonably close to linear, it should mean the venturi mixes properly by mass. I can see a reason why higher pressure should cause less than linear increase in fuel flow, but not much why it should cause more than linear increase in fuel flow—but that is what the actual behaviour would need.

Note: Did you notice the extra $v$ conspicuously missing from the last equation? That suggests the mixture should become richer with throttle opening—which is actually the reason there are extra fuel jets after the throttle that pull in extra fuel when the throttle is at idle and slightly above. It might also explan what is going on here, but would require explaining why the speed should increase when the density is lower.


texts: Can you file a flight plan to an airport whose runway is NOTAMed closed?

texts:
We're planning a flight (under IFR) to an airport where the runway is notamed closed until 1900L.  The airport authority has said it will likely be open much earlier, so we're hoping to to take off and have the runway open by the time we arrive.

Is it acceptable under part 91 or 135 to file a flight plan to an airport whose runway is NOTAMed closed?
I can't find anything relevant in the FARs or the AIM.


texts: What do manufacturers do to reduce cabin noise?

texts: It is being claimed by the Airbus that their new planes offer more sound proofing than those of Boeing, and I myself observed the same. How do airplane manufacturers tackle with the problem of soundproofing the cabin, so as to reduce the noise reaching inside from outside the plane (the engine sounds and the free stream noise)? What proportion of the total aircraft development cost would this be (approximately, say for an Airbus 320 and for Boeing 777)?


texts: What is this large engine doing on a B52?

texts:
In this YouTube video, discussing plans to use the 747 as an aircraft carrier, there is a brief sequence starting at 4 min 14 s, showing images of a B52:

What is the explanation for the very different inboard engine pod on the starboard wing? There is a current call for proposals to re-engine the B52 with eight modern engines. Was this an earlier test of moving to four larger engines instead?


texts:
There's something below the door on almost every commercial aircraft. What is inside that box? The protrusion can be seen from the interior of the aircraft.
Source


texts: Do airplanes or helicopters ever fly at night using only white navigation lights?

texts:
I've been trying to figure out if airplanes or helicopters ever fly at night with only white Nav Lights.

See this UAV video taken on July 12, 2015, 05:38 AM Pacific time in San Francisco, CA, USA.


texts: What happens if I am flying at a higher Lift/Drag ratio than required?

texts:
I created for me a table from an aircraft for Mach=0.8 for alpha= 0° to 8°
Actually, I an alpha of alpha=4° should be sufficient, so that my lift coefficient is enough, to counterbalance the weight in steady horizontal flight. The corresponding lift/drag ratio is 8.
I could now choose also alpha=8° , with a lift/drag ratio of 12.
My question: regarding the range equation(breguet) it is better to have a higher lift-drag ratio for making more range.
But I am wondering: if I choose alpha=8° my lift coefficient is greater than the one I need, so in the end, my aircraft will climb ? This would not be a steady horizontal flight.
Am I right?


texts: How much time is a commercial aircraft (e.g. A320 / B737NG families) flown manually?

texts:
FMS/FMGS computers can fly many modern aircraft between waypoints set by the crew. They find their way using aids like IRS, GPS, DME, and ILS and are able to manage route, altitude and thrust.

Mode control panel (MCP) on a B737 NG (probable source: Alessio Meneghetti on Flickr)
Most of a commercial flight can be handled by computers when everything goes as planned, air regulations don't seem to forbid such automation.
On the other hand the crew ensures flight safety, programs, engages and monitors computers, handles changes, hitches and abnormal situations, takes decisions and re-programs computers with new instructions. Some configuration changes (e.g. landing gears) are also beyond computer reach.
I'm curious to know which actions are manual and how much time is spent for them from entering the takeoff runway to leaving the landing runway, e.g. for a 2,500 NM commercial flight? What is the current trend for airlines policies regarding the use of these automation capabilities?


texts: Why are some aircraft windows painted over?

texts:
I have seen that some aircraft have some of their windows painted white. As you can see in this picture, this A340 has many windows painted white.
Why is it that?

Source


texts: Why do Boeing planes have more flap settings than Airbus planes?

texts:
The Boeing 737 and Airbus A320 are similar in size and performance. They are direct competitors. Boeing seems to have eight flap settings (1, 2, 5, 10, 15, 25, 30, 40) whereas Airbus seems to have four flap settings (1, 2, 3, Full).

What is the reason for Boeing having twice the number of flap settings? I believe it is similar on other models as well.


texts:
I would be interested to learn how GA Flight planning tools work regarding the calculation of the necessary information for flight plans where you usually would use the manual charts (performance, endurance, range...) How do these platforms provide this info? Most of the info for old planes is from the 50,60s where no digital data has been provided and manufacturers don't give away these data usually. And data like performance, endurance etc is aircraft specific and necessary to do the right calculations when I do it manually.

My goal is to provide a platform to do it digitially. What do you think is the right approach to provide data like this to the platform.

When I start planning for a flight, charts in the manual are needed to plan properly (Landing and takeoff lengths, enroute information, endurance, range) This is mostly provided just as a chart and would be great to work digitally with.


texts: What is the difference between EGT and TIT?

texts: In a gas turbine engine, what is the difference between Exhaust Gas Temperature (EGT) and Turbine Inlet Temperature (TIT)? I assume EGT is the temperature after the gas has transferred power to the turbine. Does that significantly change the temperature? Are they both proportional to engine power output?


texts: Would "wind turbine generators" in the bypass stream save fuel for jetliners?

texts:
What is the location of an aircraft's alternator, in a large airliner like a Boeing 747 or Airbus A380?

How much power does it produce in kilowatts?

And what is the possibility of installing it with fan blades? To act as a windmill/wind generator at the point where air is slowed down in a bypass turbo fan engine. I mean, incorporate it into the engine design so that it slows down the air to generate electricity, rather than using the motion of the engine.

The aim would be to reduce the amount of fuel required to generate electricity.


texts:
A friend of mine asked for some help identifying the airport in the picture below. He needs it for a geocache.

Google reverse image search was, perhaps unsurprisingly, not very helpful. We've spent some time on Google maps, but there are many airports :-). Other than that, I'm really out of ideas.

We have some reason to believe that it is located in Europe, presumably excluding Turkey and Russia.


texts: How can I convert an ICAO (Georgian) CPL to an EASA CPL?

texts:
I have an ICAO CPL issued by Georgia. The Republic of Georgia is not a member of EASA, but it is included in the category Countries with whom EASA has a Working Arrangement. I have 150 flight hours, 100 in an Aeroprakt A-22 and 50 in a Cessna.

In the future I am going to study the EASA ATPL theory course in an EASA member state and afterwards convert my ICAO CPL to an EASA CPL. Please let me know what kind of procedures do I need to follow? (In addition to sitting the exams in 14 subjects). I know that I also need to sit flight exams and I need further information about that. Is it worth converting my license to EASA or not?


texts: Could the Space Shuttle take off like an airplane?

texts:
This question got me thinking, would the Space Shuttle have been able to use its main engines to roll up to speed and take off horizontally like an airplane? (I'm not asking about getting to space, just flying around) What would the take off be like? What would forward flight powered by the main engines be like?

Did the space shuttle even carry fuel for the main engines internally? Before posting this question, I tried to find the answer myself, but I've had trouble finding any mention of it, only talk about the external tank. It seems to me you might want to have at least a little, just in case. If it did carry fuel, how long might it be able to fly for that way?

Would there have been anyway to put a usable fuel tank in the cargo bay?

(I realize that this will mostly be speculation, just asking for fun, if that's frowned upon, please let me know)


texts:
I'm wondering if there's ground radar on planes, or any fallback system other than relying on a controller, for avoiding runway incursions?

Have any studies or reports been made that show statistically how the majority of these incidents occur?


texts: What determines the maximum speeds for a particular aircraft?

texts:
Aircraft have three different maximum airspeeds:

VMO (maximum operating speed) - the maximum speed that the aircraft is allowed to reach during normal operations.
VNE (never exceed speed) - the speed that should never be exceeded during operation, even in an emergency, as flying at speeds higher than this could damage the aircraft.
VD (diving speed) - the fastest they got it to fly during testing.

What part(s) and/or characteristic(s) of the aircraft determine the values of these three maximum speeds?  Is it that the plane's engines are incapable of pushing it through the air any faster?  Would the wings snap off from excessive aerodynamic loads if it flew faster?  Is it something else entirely?


texts: How to calculate aerodynamic efficiency at minimum power conditions?

texts:
The drag polar of a propeller driven aircraft is
$C_{D}=0.039+0.071 C_L^2$.
The lift curve slope of the wing ($C_{L_\alpha}$) is 0.09/deg and zero lift angle ($\alpha_{L=0})= -1.5^o$.
Stall angle of the wing is $15^o$.

I am trying to find out the aerodynamic efficiency (L/D). Also if it even can fly with such specifications? If it can, what could be the angle of attack?


texts: Would hydrogen fuel tanks on an airplane increase lift?

texts: Since hydrogen is lighter than air, would hydrogen fuel tanks help provide lift for the airplane?


texts: How do turbofan nacelle lengths compare?

texts:
For example, compare the JT9D and the PW4000 below (both from Pratt & Whitney, both on a 747):

(Left, Right) The PW4000 has a longer forward nacelle, and a covered exhaust cone.

On the inside—apart from optimizations—they're the same engine:

(Flight) Comparison from an article titled Son of JT9D takes shape. (Click image for larger size.)

From the Airbus A330 Wikipedia article:

All three engines above on the A330 adhere to the same noise restrictions. Apart from what it says under the CF6, all of them feature an exhaust cone that converts the annular exhaust to a circular one to reduce drag.

So, is the choice merely cosmetic/branding, or is there a trade-off of sorts?

Based on the two comparisons above, I'm leaning toward ruling out noise suppression, and internal engine design.


texts: Is the F-16's cockpit pressurized? If so, why does the pilot receive oxygen from the mask (please state the correct terminology for this)? Is it due to redundancy in case cabin pressurization fails?


texts: How does the nozzle diameter affect the thrust of a ducted propeller?

texts:
I currently do some experiments with ducted propellers in which I try to figure out which effect a nozzle has on the thrust produced.
My theory goes like this: If I reduce the exit diameter of the duct the pressure is going to decrease and the air velocity and thus the thrust is going to increase. Consequently, you would want a small exit diameter.

However, in my experiments I measured the thrust of a 12x12 inch propeller at around 5500 rpm and got 20 N without a nozzle (just a constant diameter duct) and only 4 N with a nozzle reducing the exit diameter to 50 percent of the prop diameter.

These results are contrary to my theory! Does anybody have an explanation for this ? And what should I change to actually increase the thrust compared to the prop without a nozzle ?

Here are some pictures:


texts: Why was the B-52's wet wing more susceptible to fatigue than its dry wing, and not less?

texts:
After years of carrying all its fuel in the fuselage, the B-52 transitioned to a wet wing (where the wing structure is used as one or more fuel tanks) with the B-52G.

This caused severe problems with metal fatigue in the wing structure (the wet wing increased structural stresses by approximately 60% compared to the A-F's dry wing, according to Wikipedia), which was already an issue due to the increased aerodynamic stresses associated with a recent switch from a high-altitude to a low-altitude nuclear mission profile (the high-altitude mission profile having become unsurvivable due to advances in Soviet SAM technology).

However, storing fuel in the wings of an aircraft normally decreases the stresses on the wing structure (by putting as much of the aircraft's weight as possible in the part of the aircraft that generates the lion's share of its lift), alleviating fatigue and increasing the aircraft's fatigue life.  What made the B-52 different in this regard?


texts: What is the pivot point of pitch change on an aircraft?

texts:
I was wondering if there is a way to determine the pivot point when an aircraft changes pitch, assuming a standard slightly nose heavy and back elevator trimmed Cessna 172.  Will it pivot around the CG, the Center of lift, or somewhere in between.

Logically, I would think it would be "from where it is held up", but some writers stress CG.

Can you help me understand?


texts: What are the differences between FANS A, B, and C? Is FANS C commissioned?

texts: For the Future Air Navigation System, what are the differences between FANS A, B, and C? Is FANS C commissioned?


texts: Why might the crew switch off air conditioning in the cabin of a passenger jet during descent?

texts:
I've noticed on some commercial flights (most recently today in an A319) that as the aircraft descends in preparation for landing, the air in the cabin gets hotter. I also noticed that this seems to be caused by the air conditioning being switched off entirely or to a lower flow rate.

Is there a reason for the cabin/flight crew to switch the air conditioning lower/off for landing?


texts: What is the definition of critical altitude and why is important to know in Vmc graph? Also, is there any critical altitude in the Piper PA-44 Seminole?


texts: Why was the tip of the B-52's vertical tail chopped off in 1959?

texts:
When Boeing switched over from the B-52F to the B-52G in 1959, they (among other changes) lopped off the top 2.4 meters (8 feet) of the aircraft's vertical tail:
Original-height tail (here on a B-52F)

(Image by the United States Air Force, via David Legrand at Wikimedia Commons, edited by Denniss, Hohum, and Ralf Roletschek at Wikimedia Commons.)
Pruned tail (here on a B-52H)

(Image by the United States Air Force, via Trevor MacInnis at WIkipedia, via Rcbutcher at Wikimedia Commons.)
Why did they chop off the tip of the vertical tail, thereby decreasing the aircraft's directional stability and rudder authority?


texts: Why does the Tu-22M3 nose have this peculiar shape?

texts:
What is the reason behind this unusual nose shape? I am not referring only to the presence of the protuberance on the tip, but mainly to the asymmetry between the top and bottom side.

Image source

It can be seen better in the profile depiction here:

Image source


texts: In RTCA DO-260B, what were the reasons GVA was added ? Is it a replacement for something?

texts:
After digging up and reading through many documents, I have a rough picture of the evolution of DO-260 versions, particularly for its ADS-B Quality Indicators. For instance, in DO-260 (Version 0) integrity & accuracy were expressed in a single parameter called Navigation Uncertainty Category (NUC). In DO-260A (Version 1), more quality indicators were added such as Navigation Integrity Category (NIC), Surveillance Integrity Level (SIL), Navigation Accuracy Category for Velocity and Position (NACv & NACp), and many more. In fact, there were a lot of new things introduced in this version. In DO-260B (Version 2), more were added such as SIL supplements, System Design Assurance (SDA), Geometric Design Assurance (GVA), and many more.
It is important to note that the majority of the quality indicators in DO-260A were reliant on vertical components. For example, NACp is derived from Horizontal Figure of Merit AND Vertical Figure of Merit, NIC and its Vertical Protection Level, NACv and its VFOM, etc. However, in DO-260B, the vertical components from the quality indicators were removed and a new parameter called GVA was added.
I found too little info on GVA. What I know is that GVA shall be set by using the Vertical Figure of Merit (VFOM) 95% from the GNSS position source used to encode the geometric altitude field in the ADS-B message. Thus, each number on Figure 1 has a meaning. I searched about VFOM and found a schematic of it (Figure 2). Would this be a valid representation of GVA?

Figure 1

Figure 2

Sources:
 Figure 1 : RTCA DO-260B DRAFT Version 4.2
 Figure 2 : GNSS Height on Airbus A/C, Slide 5
 1. Analysis of Quality Indicators in ADS-B Messages by Simon Tesi & Stainslav Pleninger
 2. Study on Airworthiness Requirement for the Position QUality of ADS-B System by YAN Fang


texts: Is the size of hail on the ground any indication of the winds and updrafts of a thunderstorm?

texts: Is there any rule of thumb or way to estimate the wind speeds or up and down drafts inside a storm by the size of hail that reaches the ground?


texts: Why is "heavy braking" recommended in an aircraft with carbon fiber brakes in order to prevent brake wear? That seems backwards!

texts:
I get that standard brakes and carbon fiber brakes are made out of two different materials, but some of the procedures are different between them.

For instance, they recommend "heavy" braking on landing (even if it isn't required) in order to prevent brake wear.  Why is that?

What other differences are there between them that a pilot needs to know about before flying an aircraft with carbon fiber brakes?


texts: How, exactly, did US1549 land on the Hudson?

texts:
A comment by @AsheeshR says:

  The Hudson River Landing was due to a combination of piloting skill and an autopilot system that was engaged right till impact and kept the plane in a controlled descent within a safe flight envelope.

It was an Airbus aircraft, so the autopilot has priority over pilot input, but how exactly did the autopilot play a role in getting them down safely?

What exact procedures did Sully and the crew follow when landing? Was there anything in addition to standard ditching procedures, that might have contributed to them landing in one piece?


texts: In regards to achieving equilibrium conditions, what is the relation between airspeed and the tailplane?


texts: What do solo pilots do between reporting points on longer flights?

texts:
On some IFR flights, it can be a long time between waypoints. Obviously you must continue monitoring ATC for instructions, but during the rest of the "idle" time, what tasks do pilots have that keep them occupied?

I'm specifically interested in what solo pilots do.


texts: Do all passenger aircraft have a nickel cadmium battery?

texts: In the event of both the engines failing in a double engine aircraft, does the aircraft a have nickel cadmium battery to provide propulsion to make a successful landing?


texts: Is this the correct sequence of steps to convert from true course to compass heading?

texts:
I wanted to confirm my understanding of VFR Flight Planning/Dead Reckoning with relation to heading and course calculation. Is the below correct?

Using a plotter, draw a line from departure airport to arrival airport
Using the same plotter, get the true course (TC)
Using an E6B or similar calculator, calculate the Wind Correction Angle (WCA) which is based on Wind Direction and Speed
+ or - the WCA to/from the TC and the result will be True Heading (TH)
Using the chart, see what the Magnetic Declination is and + or - the value (West is Best [add], East is Least [subtract])
The result will be Magnetic Heading (MH)
On the day of flight, check the Compass Deviation Card to + or - the deviation from the Magnetic Heading and this will give us the Compass Heading (CH)


texts: What is the difference between instrument privileges and instrument rating?

texts:
According to FAR 61.153(d), a pilot may use a foreign commercial or ATP certificate as a prerequisite for getting a US ATP.

To do so, an applicant must:

  Meet at least one of the following requirements:
  ...
  (3) Holds either a foreign airline transport pilot license with instrument privileges, or a foreign commercial pilot license with an instrument rating, that... (emphasis added)

What's the difference between "instrument privileges" and "Instrument rating"?


texts:
(YouTube) A crop duster's nose mounted display.

It looks like a poor man's HUD to keep the display and the outside view at roughly the same focus distance, but what is its function?


texts: How is the transfer of an aircraft managed when it landed at a different airport than the scheduled one?

texts:
The question came to me when my flight could not land at the scheduled airport because of fog.

We landed in a nearby city (Turin instead of Milan). Is the aircraft transfered without passengers later on? Bear in mind that there are no flights scheduled between the 2 cities (120 Kms distance only).


texts: What is the difference between active tip clearance control system and passive tip clearance control system in turbine?

texts: What are the main differences between turbine active tip clearance control system and passive tip clearance control system?


texts: Why do we have to manually tune VOR receivers?

texts:
As the VOR frequency is automatically selected when the DME is selected, under what system conditions is manual tuning of the VOR required?

(aviation-safety-bureau.com)


texts: What kind of information is shown on airport surface traffic surveillance displays?

texts: What kind of information is displayed by the ground surveillance radar scope on Advanced Surface Movement Guidance and Control Systems (A-SMGCS) or similar systems like ASDE-X?


texts: Can I become a Commercial Pilot if I had OCD?

texts:
In a few weeks, I am going to get off my medication for OCD treatment. The FAA says if episodes are severe enough to cause disruption of vocational or educational activity then I should be disqualified. In the very beginning that was the case, but now school helps me not to think about it.

The FAA says if I am on medication or have suicidal ideation then I should be disqualified. Well, considering I am getting off my medication in a few weeks that means it's not a required medication, right? And I have never had any suicidal thoughts.


texts: How is it safe for helicopters and Ospreys to refuel in mid-air?

texts:
How do military helicopters like the Blackhawk and CH-53, as well as the V-22 Osprey, perform mid-air refueling without their rotor blades (periodically and accidentally) contacting the drogue or fuel hose and causing a major accident?

I imagine that if the rotor blades did make contact with the fuel hose, either the fuel would be released and be sparked and ignite, or ingested by the helicopter turbines, or the rotor would break, or all of the above!  When a helicopter is refueling, its rotor is nearly above the fuel hose, or at the maximum, maybe 20 feet away?  It's easy to imagine a bit of turbulence or a few centimeters of cyclic movement (a sneeze perhaps?) is all that it would take for the rotor to dip and come forward and contact the hose.

For the Osprey the propellers / rotors are behind the nose of the aircraft and thus farther away from the fuel hose, but still, like a helicopter the Osprey's rotors are very large, and are exposed as opposed to the concealed compressor blades of a jet turbine.


texts: What determines the noise an aircraft's undercarriage makes at the moment it leaves the ground?

texts:
In an Embraer E170 at take off, there is only the faintest clue from the undercarriage that the wheels have left the ground.

In a Fokker F70, there is by contrast a loud mechanical "clonk" that can be heard and felt very distinctly.

What's different in the design of the undercarriage in these aircraft? And what's going on in the F70 that some component of the machinery is walloping around enough to produce such a noise?


texts: What airplane is this? and why the strange inlets?


texts: Is trimming aircraft to relieve pilot of applying force on control stick/Pedal still applicable?

texts:
I know that historically pilots used to trim an aircraft to relieve continuous application of force during climb/cruise/descent, and at that trim tabs existed on control surfaces (elevator, ailerons, etc) which could be used to hold the position of the control surface without the pilot applying any force. But now, we don't usually have trim tabs, and with fly-by-wire systems forces have been reduced on the pilot.

Does trimming do anything other than reduce pilot workload? Also:

Do modern aircraft still follow this concept of trim to reduce pilot's continuous force on the flight controls?
Apart from pilot workload and fuel efficiency (I know that trimming an aircraft can produce drag), what other benefits does trim offer?
Without trim tabs, how is trimming accomplished?


texts:
What solutions are there against deep stalls?

According to SKYbrary:

  Aircraft with a T-tail design are often configured with a Stick Pusher system to help prevent the mainplane angle of attack from reaching a value that could result in a Deep Stall.

Are there other solutions?


texts: How does a runway inspection radar work?

texts:
In AC 150/5220-24 FAA mentions radar equipment to detect foreign object debris (FOD) on runways, based on stationary and mobile radars with an astronomical precision, e.g. able to detect an object as small as 3 cm at a distance of 1 km.

Xsight Systems

How do these systems work?
Do they completely replace visual inspections?
Are they common on international airports?


texts: What is the difference between a P-51 Mustang and an A-36 Apache?

texts: Both were made by North American Aviation and the planes were almost twins - the A-36 having a ground attack role while the P-51 was a fighter. Are there any noticeable differences between the two?


texts:
I used to fly a Cessna 550 with 'steam gage' mechanical gyros. The Attitude Indicator always had its flight director solidly on the horizon in level flight -- to the extent a mechanical instrument could be seen accurately.
I recently started flying a Phenom 300 with a G1000 panel. It is curious to me that level flight in the Phenom is always about 2.0º nose up pitch:

And a detailed pic of the command bars in level flight at FL430:

My question: Why would level flight be indicated by nose up pitch? What does 'level' actually refer to?


texts: What's exact offset degree dividing localizer and LDA?

texts: When a localizer is offset at an angle with the runway track, it functions as a "Localizer Directional Aid or LDA." What's the exact offset degree dividing them? Any offset degree greater than 0 makes a localizer an LDA? I've checked various sources including AIM, but none of them gives me a definite answer.


texts: What are the benefits of long-haul airplanes servicing regional routes?

texts:
Following this answer. This is actually a set of three different questions:

How often airlines "wastes" money, by putting long-hauls (widebody aircrafts) on regional or domestic routes?
Are there any (economic?) arguments for doing so (except special cases: like no other kind of replacement for broken small plane)?
Is there any example of any regional route, that is served by long-haul on regular basis?

But, I think, that all of them can be answered with one, quite simple answer.


texts: Why is a plane escorted while in technical difficulties?

texts:
In a recent incident, where the pilots of an Embraer 190 lost control and started flying erraticly in Portugal, two fighter jets started escorting the troubled plane after the emergency was declared.

Why did they escort it if it wasn't a security/military threat? What could they have done or how did they help?


texts: Is there a rule of thumb to choose an aircraft for long-haul operations?

texts:
Are there any rule of thumb for a  NEW commercial airliner, maybe 200 seater or more, for long-haul operations ? I imagine it would be -

mostly bigger aircraft as amount of fuel needed would be more
amount of food needed would be more
amount of waste generated would be more
discounts offered by manufacturer

all of which points to having bigger aircraft.

Apart from approximating number of passengers either between A or B or A - hub what sort of other factors influence what sort of aircraft would it be.

I am using long-haul definition from Wikipedia

To make it more precise - 200 or more pax.


texts: How safe is the single engine taxi out for twin engine aircraft?

texts:
Fuel conservation programs are leading to single engine taxi out, asking the crew to start the other engine near or on the position 2, where the ground crew cannot monitor the engine's status outside the aircraft.
How safe is this procedure? One example is the jet pipe fire during the start up.


texts: Is there a reason Germania aircraft cabins have blue lights?

texts:
On my 2014-01-18 CET flight ST2114 from FKB to LPA on a Germania airplane, cabin lights were switched from white to blue for takeoff. I recorded this in a panoramic photo.

Granted, on sunset, the sun coming in through the windows made up for a beautiful play of light: Blue and yellow are complementary colors.

Is there a security or technical reason for the blue light, or is it just for
aesthetics?


texts: How is the steepness of turn bank properly defined?

texts: In aviation we often refer to the bank of a turn as shallow, medium  or steep. I remember reading somewhere that the definition is not universal as to how many degrees it is, but it has to do with the airplane and whether the bank tends to roll back to level, remain where it is or continue to steepen. Does anyone know if this is a correct definition or have any references to share?


texts: Why is the TORA of 27R not the same as the TORA of 09L?

texts: 09L and 27R are the same runway but just in opposite directions. I've drawn out a diagram and for some reason the TORA for 27R is 18m less? Where has that 18m disappeared? I've been trying to work out the difference in values using only the information in the table and I still feel that 27R should have a TORA of 3902m (the same as 09L).


texts: What is lifting force of V-22 Osprey? Is any other than the two rotors?

texts:
Picture is from here.

Is any other force to lift the V22 other than its rotors? Is any possibility that the power plants their self are not generating thrust? I was just wondered that such short propellers can lift (especially when VTOL) the aircraft even with additional heavy humvee.


texts: What is the reasoning behind this question about the correct altitude to avoid clear icing?

texts:
This question has been killing me for a while and it's an original PPL question:

You are approaching to an airmass with a temperature of 6 C at
10000ft. Which altitude should you be in order to avoid clear icing?
A) 14000ft
B) 12000ft
C) 6000ft
D) 9000ft

The answer is C and I have no clue why.


texts: Is a single engine failure on the HondaJet recoverable?

texts: Is it possible to recover from a single engine failure at cruising altitude on the HondaJet and safely land the aircraft?


texts: How are in-air refuelling craft grounded to each other?

texts:
This answer mentions that before refueling equipment is connected the F-16 and the refueling vehicle must be connected to each other. This does not seem to be the case for in-air refueling.

Why is the above-mentioned restriction not practiced for in-air refueling? Is there no chance of electrical voltage potential between two flying aircraft? Are the fuel lines purged before connecting in flight? Are fuel explosions not a big problem while the craft are flying? Are in-air safety considerations lower than on-ground safety considerations?


texts: Are there ground stations at the waypoints a pilot may fly to?

texts: How is a waypoint marked? Is there a ground station present at that waypoint? And how are these waypoints named?


texts: What are the pros and cons of scimitar propellers?

texts: I know scimitar propellers are used to reduce noise, but what is their downside? There has to be one, considering most propellers don't use that shape.


texts: Could the Busemann's biplane concept be used in a turbofan engine?

texts: Would incorporating the Busemann's biplane concept in the turbofan engine fan blades and engine casing make it more efficient, if fan tip speeds were allowed to move above the speed of sound by cancelling out the sonic boom and sonic shock waves?


texts: So, the question is in the title. Specifically referring to this video. At around timestamp 2:10 in the video, you can see the GS and LOC indicators blink. Why does it blink?


texts: Are helicopter searchlights fixed or movable?

texts:
Can the helicopter crew move the helicopter searchlights or are they always fixed at a specific location on the helicopter?

They are used by rescue helicopters mostly but I am not sure if crew can move them to look at specific area by some method or they are always fixed.


texts:
Similar to a card hitting the spokes of a bicycle, the card is soft enough to knock the dust off the spokes with no damage. What material would be best to impede the propellers to chip off the ice. Assume the flexible rod is machine held. What heavier duty impeller could be used for this? What about the same idea for a helicopter rotor?
I apologize for the multiple questions but they could not stand alone on their own. If it an issue let me know.


texts: What are the US flight planning regulations for an alternate airport?

texts:
As I read 14 CFR 91.169 literally, I understand an alternate airport listing waiver can be granted if the destination airport

Has at least one instrument approach procedure from an authorized source.
reports/predicts within ETA ± 1 hours, ceiling 2000 or higher, 3 SM or greater (1-2-3 Rule)

Q1) So one case, If we plan an IFR flight to an airport without any IAP, even if the whole area is SKC, we are legally required include an alternate airport?

As for the alternate airport qualifications, I get the following following flow,

Is there any weather reporting or forecast service at this airport?

Yes, Go to Step 2

No, return Unqualified Alternate.
Does the weather good enough for basic VFR descend from MEA, approach and landing at ETA?

Yes, return Qualified Alternate

No, Go to Step 3.
Does the airport have an IAP?

Yes, Go to Step 4

No, return Unqualified Alternate.
Is your airplane WAAS-equipped?

Yes, include GPS approaches in your candidate IAP pool. Go to Step 5

No, remove all GPS approaches from your candidate IAP pool. Go to Step 5.
Remove any IAP with unmonitored or inoperative equipments from your candidate IAP pool. Go to Step 6.
Find the alternate minimums for each IAP in your candidate IAP pool from Step 5, or if no alternate minimum is published apply 600-2 for precision approach and 800-2 for non-precision approach. Go to Step 7.
Compare the your lowest minimums from Step 6 with the weather report or forecast at alternate airport. Is your lowest minimums greater than the weather minima?

Yes, return Qualified Alternate.

No, return Unqualified Alternate.

Q2) Does this flow reflect the current FAA alternate airport requirements?

Q3) In an actual approach to the alternate, can we first attempt an approach that is different from the one we used to satisfy the alternate weather minimum planning requirement? (the one selected from Step 7 for lowest minimums). Technically, The IAP to use is not a required part of a flight plan.


texts: How to join a traffic pattern when passing overhead?

texts:
I can't seem to find a definite answer to the question on how to enter a traffic pattern when joining from the opposite end of the pattern. No matter who I ask, I'm getting a different answer every time, and they all seem convinced it's the only way to go.

So I'd like to ask a broader audience here.

Let's say runway 36 is in use, right traffic and you approach from the west. How do you enter the pattern?

I'm convinced "B" is the right way (safest at least) but recently I heard an ATC conversation where the pilot was instructed to cross overhead and join downwind. He used method "B" but the controller didn't like that because it took too much time.

What is the correct way? Is there a difference between controlled and uncontrolled airports? What about the procedure when approaching from other angles? And is there a difference between the U.S. and other parts of the world?

EDIT:

On March 13 2018, the FAA released the following Advisory Circular regarding this matter: AC-90-66B.


texts: Would biplanes be of use in VSTOL applications? What is the down side to biplanes? ex. Bush Pilots or VSTOL competitions

texts: I feel like bush pilots and VSTOL competition aircraft could use biplanes to work much better. Granted, range and speed are decreased, but besides overall efficiency, what is the down side to biplanes?


texts: How do aisle lights show the direction to exits?

texts:
Lights in the aisle will guide you towards an exit.

I've sat through a lot of safety briefings (for commercial scheduled passenger flights) and always found this sentence especially uninformative. Usually the cabin crew pantomime will include some vague gestures towards the floor of the aisles at this point, but even with airlines that use pre-produced videos for their briefings it seems that the video never actually shows those guiding lights in action.

Are they moving dots of light in the floor that chase towards the nearest exit row? Are they fixed lights that are shaped like arrows, pointing to the exits? Or just a strip of light that will tell me, "here is the aisle", but I'll need to figure out by myself which way along it to crawl?


texts: What is this tube-like thing protruding from under an A330's wing?

texts:
I took a flight for a business travel and I saw something new for me on the wing. I highlighted that part in a red circle in the picture below. The aircraft is an Airbus A330-200.

What is it and its function? I know the anti-shock bodies and static wicks, but what's that?

As a contrast, there isn't such a thing on this other aircraft, an A320, except a static wick.


texts: Where are elevators located in aircraft with delta wings?

texts:
Where were elevators located in aircraft with delta wings, notably the Concorde and the Blackbird SR-71?

If they didn't exist, how did these aircraft perform the nose up maneuver mid-air and at take off?  Why didn't they need elevators?

As mentioned in the comments:

While the other question is the same, the answers don't mention the distance between the CG/AC and the elevons (large moment) nor the stabilizing effect of the long delta wing (or the presence of canards on the TU-144). So there is room to improve it.


texts:
Our teacher gave us an assignment where we have to study the longitudinal stability of an X-15. I have to study it at 353.9 m/s which is Mach 1.2. Another group has to study it at 235.9 m/s so Mach 0.8.

I made a Matlab code computing the eigenvalues of the A matrix because I have to plot the phugoid and the short period modes. With my speed I get :

Eigenvalues [at 353.9 m/s]:
  -0.6094 + 3.1782i
  -0.6094 - 3.1782i
  -0.0775 + 0.0000i
   0.0473 + 0.0000i

While with the other speed I get:

Eigenvalues [at 235.9 m/s]:
  -0.4093 + 2.1175i
  -0.4093 - 2.1175i
  -0.0070 + 0.0649i
  -0.0070 - 0.0649i

In the second case, it is clear that the phugoid is the -0.0070  ± 0.0649i and the short mode is  -0.4093 ± 2.1175i. While in the first case, what can I deduce ?

Is there a dynamic mode which is cancelled by the supersonic speed?

EDIT: The A matrix is the coefficients of the longitudinal motion equations:


texts: What are the unusually-enlarged wing sections on this P-38 Lightning?

texts:
Halfway through this video of the Lockheed P-38 Lightning, there's an unusual-looking example.  Notice the enlarged wing sections outboard of the engine bodies, and also how the cockpit fairing extends further aft than usual.

No other P-38 in that video has those features.

What were these devices (and their purpose)?

Also, what is all that gadgetry at the trailing edge of the port wing at its root (with respect to the port engine body), and also that L-shaped thing trailing behind?


texts: What effect did the AWACS radar dome have on the stability of the 707?

texts:
The large disc shape of the AWACS radar dome, and its attachment pylons to the fuselage, above and behind the wings, seem to have the potential to actually improve the pitch and yaw stability of the 707 carrier aircraft in spite of its ungainly appearance.

In light of the current debate over placement of increasingly large fan jet nacelles, could stability data from the AWACS radar dome configuration inspire improvements in current designs?


texts: Why are there 4 hands on the throttles of this B17 during takeoff?

texts:
I watched a video of a a B17 taking off, and as you can see on the attached image, there are 4 hands on the throttles: the PF's right hand, both PNF's hands, and even the F/E has his hand under the throttles.

What's the reason for that? I understand the policy of the PNF having his/her hands on the throttles (as explained in this answer, for instance), but what about the F/E, what is he holding?


texts: Do landing strips suffer from potholes or rutting?

texts:
In companion to the other question asking about wheel tire tracks.

Planes come down and stop with a significant amount of force which I would expect to cause either rutting or potholes.

Are runways susceptible to ruts and potholes?

And do these cause significant issues for landing planes?


texts: Why does the DHC-6 pitch down when the flaps are retracted, rather than up?

texts:
Air Moorea Flight 1121 crashed because one of its elevator cables broke immediately after the pilot retracted the flaps, but before he could trim out the resulting pitch-down moment - to quote the English translation of the BEA report,

The operator called for the reduction in engine RPM before retraction in order to mitigate the pitchdown moment caused by the flap retraction and so that the right hand, after having positioned the flap control lever on 0°, could be placed be placed on the elevator trim in order to reduce the effort on the control column. [report page 17/PDF page 19]
...stick free, the flap retraction led to a pitch-down moment varying the aeroplane trim between 20° and 30°, the rate-of-climb indicator going to stop at less than 3,000 ft/min and speed reaching 140 kt in twenty seconds… [page 42/44]
In flight, the loads on the cable are at their greatest when it is necessary to counter the pitch moment induced by the retraction of the flaps. [page 61/63]
The malfunction occurred at the top of the initial climb, passing through 350 feet, when the pilot retracted the flaps then adjusted the engine parameters. While he was adjusting the parameters with his right hand, he was holding the wheel with his left hand while pulling back to counter the pitch-down moment and stabilise the airplane on its flight path. It was only at the end of this process, which lasted nine seconds, that he would adjust the trim.
[...]
The flight tests showed that during flap retraction, when pitch control is free, the airplane dives with a high pitch angle. [page 63/65]

and, finally,

The DHC6 Twin Otter has significant pitch-down moment when the flaps are retracted. [page 67/69]

How can this be?  Flaps extend downwards from the trailing edge of a wing, and, thus, should always produce a pitch-down moment when extended (like applying nose-down elevator, except with a much shorter moment arm), and a pitch-up moment when retracted.  Why is the DHC-6 different in this regard?


texts: Why would a cylinder not work below a certain RPM?

texts:
We have an IO 540 Lycoming engine, and cylinder #3 doesn't work below 1900 RPM (cold to the touch; EGT and CHT are zero; no vibration). The engine is new, what could be the cause(s)?

We cannot contact the company.


texts: Is drag coefficient lowest at zero angle of attack?

texts: The drag coefficient of a symmetric airfoil is lowest when its angle of attack is zero. I'm not sure if this is true in general.


texts: Can commercial aircraft dump luggage or cargo mid-air?

texts: In a situation where the pilot realizes that weight of the aircraft is too high, can they dump luggage / cargo mid air, similar to dumping fuel?


texts: Can I count simulator hours towards a commercial flight certificate training?

texts: I attend a Part 141 training school and have a total of 98.5 hours of flight training towards a commercial certificate, with 8 hours of simulator training, also for the commercial certificate. Can I count both the flight and the sim hours towards the aeronautical experience for the commercial certificate? It would be a lot cheaper and faster to reach the required 120 hours this way. The Beech Baron is not cheap to rent!


texts: Would formation of the three planes benefit from increased distance of the ground effect?

texts:
I know that the ground effect quickly diminishes as altitude above the ground increases, and it is roughly half of the wing span. Hence it can be used to fly more economically over water, but over ground normally would not be high enough.

I have envisioned two larger airplanes "helping" the smaller one in between by flying next to it as shown in the diagram. By idea, wings of the all three planes would form much longer "superwing" with the ground effect equal to the complete wingspan of the larger plane plus half of the wingspan of the smaller plane in center. This would be much higher than the small plane could do alone (half of its wingspan), maybe making possible to use the ground effect also over ground. The small airplane would then need less effort to fly, if it is, for instance, low on fuel.

Of course, the obvious problem is that the wings cannot "join", it must be some reasonable gap there to avoid the collision.

Would the central plane flying in formation as shown in the schema experience a stronger ground effect than flying alone?


texts: How can flying high minimize drag and increase fuel efficiency?

texts:
As a plane goes higher, the engines have to work harder to compensate for the air density, therefore it will require more fuel in order to provide the same power at lower altitudes.

But I always hear that flying high means less fuel burnt.

How can that be the case?


texts: Are there any hypersonic planes in service today?

texts: Are there any hypersonic (Mach 5+) planes in service or officially being built? Or all the talk I here about the SR-72 rumor. Thanks!


texts: Can a pilot change out of uniform during breaks on a long flight?

texts:
How long is a pilot-in-command's break on ultra-, or long haul flights? Would they be required to keep the uniform on, or would they have the freedom to change out of uniform?

Related: How do pilots rest on long-haul flights?


texts: Why do some airplanes allow separate right and left rudder pedal adjustment?

texts:
Ideally, when a pilot adjusts the rudder pedals both pedals should move together, to have equal leg length for the left and right legs.

Some aircraft like the Dornier 228 have rudder pedal adjustments where you have to adjust the left and right rudder pedals separately. What is the logic of having provision for separate adjustment of the left and right leg length to reach rudder pedals?


texts: If unable to procure Helium, are there any regulations against filling lighter than air craft with Hydrogen instead?

texts:
The price of helium is going up again, and it is very difficult to find suppliers without established contracts.  If all possible safety measures are taken, are there still regulations by FAA or other that would prohibit use of hydrogen instead for buoyancy in lighter than air non-thermal aircraft?

The causes of the Hindenberg fire are well documented and studied so lessons learned such as sudden grounding when aircraft surface has accumulated significant electrostatic charge can be avoided through measurement and continuous static dissipation techniques used on current aircraft.


texts: How are altitudes handled with airports near or above transition altitude?

texts:
Transition altitude refers to the altitude above which all altimeters are set to a standard pressure setting (typically 29.92 inHg) instead of to the local surface pressure, and altitudes are given in flight levels (the standard-pressure altitude, divided by 100; for instance, with one’s altimeter set to standard pressure and reading 52,900 feet, one would say “flight level 529” rather than “52,900 feet”) rather than in feet above mean sea level (MSL).  The height of the transition altitude depends on where you’re flying; for instance, transition altitude is at 18 kft in the United States, 10 kft in Australia, and as low as 6 kft or even lower in parts of Europe.

Low transition altitudes raise the possibility of an airport’s height above sea level being close to, or even above, the transition altitude; this wouldn’t be an issue in the United States (where only the very highest one or two mountain peaks reach above the 18-kft transition altitude, and this altitude is well into the Death Zone anyways unless one is exceptionally well-acclimated to very high altitudes) or Australia (where even the highest peaks are less than 8 kft above MSL, well below the 10-kft transition altitude), but could easily become a problem in regions with both high terrain and low transition altitudes (such as Europe, which has many high mountains - and, more to the point, many airports high up in mountainous areas - combined with transition altitudes that go at least as far down as 6 kft), as maintaining terrain clearance requires knowing what one’s altitude actually is, rather than knowing what altitude the pressure at the static ports would correspond to if the local altimeter setting was 29.92 inHg.

How do airports located at elevations near to, or above, transition altitude handle this?  Does the airspace around these airports use a local transition altitude higher than elsewhere?  Do approaches and landings at, and takeoffs from, these airports rely solely on radar, rather than barometric, altimeters?  Something else?


texts: Is there a standard for required repainting of worn runway markings? In USA

texts:
Is there an FAA regulation or advisory circular covering the allowable wear, fading, or weathering of runway markings? I can find many FAA standards for the paint of fresh new runway markings, but I can not find any standard for determining when markings have become unacceptable due to wear or weather. It seems disconnected to create many specifications for new paint visibility but then to have no wear limits.
I am interested in federally funded or part 139 airports.(139 airports serve scheduled passenger service with more than 30 seats) I understand that private airports are not required to have standard markings.
There is a local public airport with center-line marks so old they cannot be easily seen from the traffic pattern, or final approach, even on a clear day.(the numbers and threshold bars are in good condition) I can still see the center-line paint when on the ground for takeoff and rollout. (no tower, but it does have a non-precision instrument approach and a dozen+ operations per hour in good weather)


texts: Why has the bell distribution not become widely used? Is the bell distribution only ideal in inviscid flow scenarios or is there another reason for the lack of use?


texts: Where can over age 65 airline pilots fly?

texts:
Some countries have no maximum age for airline pilots while many other countries specify age 60 or 65. (Austria, Russia, Canada, Australia, etc., have no maximum age)

ICAO rules currently specify a max age of 65 which allows ICAO member states to fly into countries where the max age is only 60.

Does this rule apply to only landing and taking off, or also to in transit overflights?

For example, could a flight depart Canada, overfly American airspace, and fly to Australia with crew members older than 65?

If not, what about a flight from two bordering countries like Canada to Russia?


texts:
I've read that some radars can detect stealth aircraft or aircraft with low radar cross section but are not powerful enough to allow a "weapons" track or allow a missile or another aircraft to lock on to it.
What is the difference between the 2 radar tracks? Is one less accurate in terms of pinpointing the aircraft range by a few meters or kms?


texts: What does I1001 mean in a METAR remarks?

texts:
Here is an actual METAR example:

KOMA 190352Z 36017G26KT 3SM -SN OVC012 M08/M11 A3014
RMK AO2 PK WND 36027/0302 FZDZE37SNB27 SLP220 P0000 I1001 T10831111 $

What does the I1001 mean? I have also seen I1000, I1002, I1003, and I1004.


texts: Where can I find documentation that state sales tax was paid in the 1980s when an aircraft was purchased?

texts:
I am going from a sole owner to a partnership with two others in a Cherokee 140.  The state wants proof that state sales tax was paid in the 1980s when a family member originally purchased the airplane.

I have informally been a partner in the airplane since that time and have been paying half the bills. My partner recently passed away. I'm sure the state sales tax was paid but cannot find any documentation. They won't process the new registration until I can provide documentation that the state sales tax was paid, or I have to pay the fee again.

Where can I find a record that the state sales tax was paid when the aircraft was originally purchased by my family member?


texts: Is it possible to fly an ultralight aircraft with a 13.4kW engine?

texts:
I want to build an ultralight within the 115kg preload (US standard). Can I use and engine with the specifications below? My weight is around 63kg.

Rated output: 13.4kW(18HP)@3600RPM


texts: Can an aircraft be turned without rudder input?

texts: Is it possible for pilots to make a right or left turn, using just the ailerons and without rudder input in all airliners? If not why so, for what reason?


texts: What would the density profile of this shock wave look like, roughly?

texts:
The YouTube video titled Shock Wave Formation in Transonic Flight shows a hand-held video of a visible shock wave extending from the top of a jet engine near the front. The shock wave is visible by its refraction of features on the ground (muddy river bed) cause by the large changes in air density over short distances.
I would like to simulate the optics of this strictly for fun and general interest. If one made a simple plot of the density as a function of position crossing the shock wave, roughly what shape would have?
I've plotted six simple examples of shapes, perhaps one is appropriate, but perhaps something else is better.
below: GIF made from this video around 00:31.

below: some example guesses of the density behavior across the part of the shock wave seen to refract ground features in the video.

below: Description from this video.

Published on Oct 18, 2012
Formation of a shock wave around the engine cowl of a Boeing 767 at high speed.
The aircraft itself isn't going supersonic, but it's going fast enough (probably around Mach 0.8) that the local airflow around the engine cowl is supersonic, in a small area. This is called "transonic," and results in the formation of a shock wave at a right angle to the surface of the plane. The air in front of the shock is supersonic, and the air behind it is subsonic.
The shock wave is visible because of the abrupt change in the density of the air. The change in density causes a change in the refractive index of the air, and so the scenery behind it is optically distorted. This is similar to how a spoon in a glass of water looks "bent" at the water's surface, due to the difference between the refractive indices of water and air. It helps that this is seen nearly edge-on... if I had been a couple of rows further forward or back, it might not have been visible.


texts: What is the difference between active and passive sidestick?

texts:
What is difference between "active" and "passive" sidestick?

Which aircraft have active sidestick?


texts: How should this ODP be flown if heading east?

texts:
The KFDK departure procedure for RWY 23 states:

  DEPARTURE PROCEDURE:  Rwy 23, climb heading 229° to 1200 before turning right.

Does this only apply if making any sort of right turn after takeoff i.e. to the west? If my course was east or south and would I still need to climb to 1200, make a right turn, and effectively make a right climbing turn to fly back over the airport to get on course?


texts: May time be logged for an aborted flight?

texts:
Consider the case where the engine is started, aircraft taxies to the run-up area to do check, then it turns out that a magneto is bad, or there's a radio problem. The pilot wisely decides to abort the flight, and taxies back to parking. In the process, experience has been gained in taxiing, possibly ATC communication, the pre-flight, and good pilot judgement for the flight. There were no take-offs, landings or air time, but the aircraft was under the control of a PIC during taxi.

There's a long discussion about this on PPRuNe, with varying opinions either way.

According to 14 CFR 1.1:

  Flight time means:

  (1) Pilot time that commences when an aircraft moves under its own
  power for the purpose of flight and ends when the aircraft comes to
  rest after landing; or

  (2) For a glider without self-launch capability, pilot time that
  commences when the glider is towed for the purpose of flight and ends
  when the glider comes to rest after landing.

The key phrases seem to be for the purpose of flight (which seems to be satisfied - unless going for a VOR check, or moving the aircraft from one location to another), and after landing (which, doesn't apply, because there was no airborne time).

Have there been any FAA determinations, rulings or enforcement actions made in this regard?


texts: Why do pilots say "clear of the active" at non-towered airports?

texts: At the non-towered airport I fly at, pilots when clear of the runway always say "X Traffic, Skyhawk N123 clear of the active." Why not say the runway number? At a one-runway airport, I understand that this could be redundant, but wouldn't it be better to get in the habit of saying the runway number so that--should there be more than one runway--it wouldn't be an issue?


texts: Are DME arcs coded in the CIFP data file?

texts: I use a git project (https://github.com/rstory1/parseCifp) to transfer the FAA CIFP formatted file into a database, but noticed that DME arcs don't seem to be carried over. Looking into the FAACIFP18 file, I can't seem to find it either for some sample airports (e.g. KMTN). Any FAACIFP experts who can chime in on where exactly they are published in this cryptic format, if at all?


texts:
TAFs (terminal aerodrome forecast) have different durations. Some forecasts 30 hours into the future while others forecasts only 24 hours.
But what is the shortest and longest TAFs? and how often are TAFs updated?


texts: How much time does it takes to buy a landing slot?

texts:
According to Wikipedia, landing slots are sold for several million dollars at busy airports such as London Heathrow. Given this high value, such transactions may take weeks to conclude. Moreover, some slots can be free quickly and unexpectedly (e.g. when a company cease activity).

My question is: for the busiest European airports (Heathrow, Schiphol, Charles de Gaulle,...), how much time does it take to complete these steps (and the steps I cannot imagine):

The airline decides to open a new route
The airline identifies the slot they'll buy
The airline begins negotiations to buy the slot
The airline acquires the slot
The airline can operate this slot
The airline begins to use this slot


texts:
How does conventional flight work?

Explain what factors are in play in order to get a plane airborne and stay there.


texts: What is the difference between landing weight and end-of-mission weight?

texts:
Raymer says:

  Landing is much like taking off, only backwards!....Note that the aircraft weight for landing analysis is specified in the design requirements, and ranges from the takeoff value to about 85% of takeoff weight. Landing weight is not the end-of-mission weight, because this would require dumping large amounts of fuel to land immediately after takeoff in the event of an emergency.

What is the meaning of the last sentence: "Landing weight is not the end-of-mission weight, because this would require dumping large amounts of fuel to land immediately after takeoff in the event of an emergency"?

How is the aircraft design is affected by such different needed kind of weight?

(Source: Raymer: Aircraft Design – A Conceptual Approach Chapter "17 PERFORMANCE AND FLIGHT MECHANICS" Paragraph “17.9 LANDING ANALYSIS ”)


texts: Why is the A380's fuselage designed with a flat bottom?

texts: I want to know if there is some explanation for why the A380 bottom is flat instead of the oval shape, just near the wings.


texts: is an aircraft like this legal in Alberta, Canada? It's basically a human sized quadrocopter. If so do you need any license?


texts: Is it always advisable for passengers to wear seat belts when a 747 is on final approach?

texts: I noticed in this recent video that some of the passengers are not wearing their seat belts. I realize this is not a typical commercial flight, but is it advisable to wear seat belts when a 747 or similar aircraft is flying so close to the ground, (apparently) during a final approach? Or are the safety precautions here so thorough that it's not actually necessary in this case?


texts: What is the role of a flight control computer during a steep approach?

texts:
I am working on a flight control computer (Bombardier) where I got a bunch of requirements for steep approaches. All they do is 'engage steep approach' or disengage it after determining if it is safe to engage the steep approach.

Even after engaging the steep approach, if the pilot does not configure the flight properly (throttle, flap, slat settings) then it disengages the steep mode and informs the pilot.

After carefully going through the requirements, I did not find anything that the flight control computer does during the steep approach.

So is all that the flight control computer does during steep approaches to monitor it and display steep engage or disengage messages?
What would a pilot do if steep approach was to disengage when he reached below 200 ft? (Breaking off from steep approaches, I understand, is the result of losing some of the sensors, jamming of actuators etc..). Can a pilot 'go around' even if the altitude drops below 200 ft (decision height of CAT I landing)?
Is there a possibility for the aircraft to stall while trying to descend steeply?


texts: Remote access to Area Forecast Discussion

texts: Is it possible to access Area Forecast Discussion via SMS?  I fly to remote areas frequently (Wilderness), and after several days, it is almost impossible to get a good weather forecast, (one you're willing to bet your life on).  I wish I could get the Area Forecast Discussion via SMS over my inReach.


texts: Why are high-g requirements so important for training next generation of fighter pilots?

texts:
Background

In the development of T-X program, a major step has been the refining of the technical requirements, in particular this "sustained G" maneuver:

  The sustained G maneuver shall be flown with a standard configuration (i.e., clean with no external stores), at or above 80% fuel weight (relative to
  maximum fuel capacity), steady state flight, and standard day conditions. The maneuver will begin in level flight (flight path angle no lower than zero
  and no higher than two degrees nose high), wings level (+/‐ 5 degrees of bank), at or above 15,000 feet pressure altitude, and at or below 0.9M. From
  this point, the pilot shall immediately initiate bank and back pressure to achieve the sustained G. The sustained G must be maintained for a minimum
  of 140 continuous degrees. The pilot may begin reducing the load factor and rolling out after a minimum of 140 degrees in order to roll out at
  approximately 180 degrees of turn. The sustained G Threshold:  ≥ 6.5Gs; The sustained G ≥ 7.5Gs.

seems to be quite challenging for the T-100 from Alenia and the BAe Hawk.

Alenia T-100 is still bidding after changing partner.
BAe, which partnered with Northrop Grumman, discarded the Hawk in favour of a clean sheet design.
Boeing/Saab participate with a clean sheet design.
Lockheed proposing the T-50 after discarding a SkunkWork clean sheet design.
Textron Scorpion seems to have pulled out after the new set of requirements.

Trend
The new requirement seemed to challenge the existing design. The Hawk could be considered "old" (first flight in 1974), the scorpion could be considered "simple". The T-100 and the T-50 starting development mid 90s together with international partners (Italy/Russia,USA/Korea) should though be "modern" trainer. While the T-100 seems to be more challenged, Lockheed considered a clean sheet design as well, so was probably not too relaxed about the T-50 performance .

Question
 - Why is this request for maneuverability so important for the next generation of fighters?
 - Should not be other factors like battle-space management more important?


texts: How long to clear the 'suck zone' of a turbofan after start is initiated?

texts:
I recently found this (IMO funny) picture. All funny and all. But let's make this a real situation.

Let's suppose I see my crush and his BF doing this, and I come with this 'genius' idea (alright, it's anything but a genius idea, but still) to start the engine they are sitting on. And no, I am not nice enough to turn the beacon lights on.

How likely is it that the engine gains enough suction to suck them in without they noticing it in time (considering the fact they need to standup and run for their lives)?

How long does it take for the engine to spool up enough suck a person in?


texts:
In February 1922 one or more aircraft flew over the Vatican low enough to disturb the papal conclave then underway. In response, authorities forbade flights over all of Rome until the conclave was concluded.
About seven years later, the Lateran Treaty between the Holy See and the King of Italy included a provision forbidding flights over Vatican City.
Various changes both in technology and in regulation of aviation have happened since that time. Ninety-one years after the aforementioned incident, Pope Benedict XVI announced that he would resign as of the last day of the month, and on February 28 he boarded a helicopter in Vatican City to fly to Castel Gandolfo.
What are the current rules and practices on flights over Vatican City?


texts:
Extension area(E airspace) shown as shaded magenta start from 700AGL but how to measure 700AGL over the water like in this picture?
Cuz there’s no land…


texts: Is it unusual for an aircraft to flash its landing lights in sequence?

texts:
Walking this evening I looked up and saw a plane which I assumed was on approach to Liverpool John Lennon. When I looked carefully I could see that as well as the anti-collision strobes it was flashing two lights in sequence. I assumed they were the landing lights as they were very bright and positioned towards the wing tips. However, they were clearly flashing one at a time, left then right.

I've never seen this before, is it normal and does it signify anything?


texts: Where do I find charts like this for Europe or Global

texts:
I am playing Xplane11 and I am trying to find charts like this

But for Europe or USA and shows every ILS approach, detalied maps etc. For europe I have found one site such as http://www.uvairlines.com/admin/resources/charts-europe.htm but it does not show every airport. Is there a site that shows for any airport ?

Note: I am looking for free sites, not sites like navigraph.


texts: What aspect ratio is best for Wind Tunnel Testing an aerofoil with Small Additives?

texts:
Vortex generators will be 3D printed on a panel, which is then to be slotted onto a foam aerofoil to be tested in the wind tunnel for performance and flow physics.

What I want to know is which aspect ratio to use?

Rectangular wing, need a chord length and span.

Max wing span is 700mm.


texts: What is the difference between a business jet and a regional jet?

texts:
At first glance, business jets and regional jets seem virtually identical - both are small jets, usually low-winged twinjets (unless they're by Dassault, in which case they're trijets) with tail-mounted engines and T-tails.

What differentiates, say, a Legacy 600 or a Falcon 9 or a G650 or a Learjet 75 from a DC-9 or a CRJ-100 or an F-28?  Is it merely who operates it?


texts: Why does a missile have small wings but better agility than a plane?

texts:
An anti air missile has often very small wings but out performs a fighter aircraft, e.g. much higher g-load, since g-load comes from lift which is the area of wing.

Why not designing an aircraft like a missile? E.g. low drag, high agility.


texts: Why is there no alert if shutting down a running engine during flight?

texts:
In reference to Flight 235, there is a lot of speculation going on today, and since the flight recorders' data indicate that the running engine was shut down manually, everyone is suspecting that probably the pilots made the mistake to shut down the running engine instead of the faulty engine to attempt a restart.

If that was the case, why can't there be an alert to warn the pilots that they are shutting down the working engine?

In the software world, we attempt to create so many fail safe situations to avoid letting users mistakenly take an action which will kill the process, why can't that be done for a multi-million dollar aircraft where so many lives are at stake?

P.S: I know these are all theories and not any official crash investigation reports but I am curious as to how such suggestions can even be made? Even my radios for radio-controlled airplanes provide many fail safe features.


texts: Can an FAA Pilot Examiner accept BasicMed in place of a medical certificate from a checkride applicant?

texts:
This has been a subject of debate recently. §61.23 states that you can use BasicMed to apply for some certificates or ratings but limits this to gliders, practical examination in a simulator or flight training device and balloon categories. For other ratings, unless you were a former pilot with the armed forces and applying for a conversion of your military ratings, you must present at least a valid third class medical certificate to a pilot examiner when applying for a rating.

I talked with the FAA Medical Certification Division and they seemed to think one could apply for a airman certificate using only BasicMed.  does anyone out there know if Pilot Examiners in the field are accepting BasicMed with a valid driver’s license from checkride applicants?


texts: Does/Can combustion instabilities occur in SCRAM jet?

texts: I was told that combustion occurs at Supersonic speeds in SCRAM jet. So acoustic disturbances/ pressure fluctuations can't travel into incoming jet stream. Does this avoids combustion instabilities in SCRAM jets?


texts: When is an aircraft considered dispatched?

texts:
When is an aircraft considered to be dispatched?
Before an aircraft is dispatched certain pieces of equipment must be operational on an aircraft.  If some equipment is found to be inoperative, a determination can be made of whether or not to dispatch based on the information found in the MEL or CDL.
After an aircraft has been dispatched, disposition of inoperative equipment would follow the guidance inside the AFM.
Simply put, at what point does the dispatcher / crew switch over from relying on the MEL / CDL to the AFM for guidance?  The pilot in command has the final authority to takeoff so I am not asking about equipment that are significant to the operation of the airplane.
I am interested in both FAA Part 121 airline operations, Part 135 charter operations and Part 91 flights.
Thanks


texts: What will happen to the IDG disconnection mechanism if we press and hold it for more than 3 secs?

texts: I read in the Elec systems chapter that if we press and hold the IDG pushbutton for more than 3 secs it’ll damage the disconnection mechanism. What exactly happens? Also it says that not to disconnect it if the engine is not running as if we do and then start the engine it’ll damage the IDG. How does this happen?


texts: Helicopter mast bumping in low g condition

texts:
The helicopter shown in the concrete pouring video seems to taking off from a hill and descending down in a way which can be classified as low G with low rotor loading. Although, the helicopter is three-bladed, mast bumping should be less of an issue, but from my understanding still worth considering.
Could a maneuver like this be executed in a similar way with a two-bladed helicopter such as a Bell 206 or Robinson. Furthermore, what is the reason for mast bumping being less of an issue for helicopters with more than two blades?

The famous video of the US Army seems to be describing exactly the condition as shown in the first video as potentially dangerous.


texts: In what order are the fuel tanks on the MiG-23 used? In other words, which tank is used first, then second etc.?


texts: Vintage army Kollsman altimeter - any info?

texts:
I have a vintage Kollsman altimeter A.C. U.S. Army. I can't read the text on the front because of the needle arms are in the way, but might state:

Type 5
Serial No A 464.

Back plate is very hard to read, but does state:

Kollsman Brooklyn NY.
Then possibly: Order No.  W. 636 AC 4708  or W. 635 AC 4798

Any info on it or what aircraft it came from?


texts: Where can I download the flight plan data around the world?

texts:
Where can I download the flight plan data around the world, so that I have analyze their route?

Are they provided freely?


texts: Which airplane designs have the greatest longevity?

texts:
What airplane designs have been around the longest, from first flight through last retirement from active commercial or military service?

My guess is that the DC-3 will win, since it has been around since before WW II and is still in service, although there are enough other designs out there I'm not familiar with that I'll be interested to see where I may be wrong on that. (Russian designs come to mind as an obvious source of possibilities.)

Can anything out there beat the DC-3? What's the runner up?

(The wikipedia page on the DC-3 says its first flight was December 17, 1935.)


texts: Is it technically feasible to make a solar hang glider?

texts: Is there any hang glider with solar sheets on top that can charge the e-trike or the e-Lift's battery in flight ? Just like the Sunseeker...


texts: Is it true that different variants of the same model aircraft don't require pilot retraining?

texts:
I'm referring to this Wendover Productions video - The Economics That Made Boeing Build The 737 Max.
The creator asserts that designing a new long range narrow body plane would be more expensive than modifying an existing design, which is uncontroversial enough.
But he also makes the claim (timestamp 6:13)  that there was pressure from American Airlines to provide a re-engined 737 over a new model, because existing American Airline pilots are already trained to use the 737.

Pilots are generally trained to operate just one type of aircraft. Some fly the a380, some fly the 777, some fly the a320, and some fly the 737, but they don't fly the 737-700 or the 737-800 or the 737-900, they fly the 737 airplane as a whole.
Pilots are trained to the aircraft, not the specific aircraft variant.
In general, pilots can and do switch between variants of aircraft even in any given day and are not required to do any substantial training to be certified on different aircraft variants.
Crucially, the FAA has never required that 737 pilots complete any simulator training before flying new 737 variants.
That's because a 50 year-old 737 more or less flies like a 1 year-old 737.
American [Airlines] wanted a refreshed 737 over a new plane since they already had thousands of trained and certified 737 pilots.
They had no pilots for a hypothetical new narrow-body Boeing and the cost of training their pilots to a new plane would be massive.

Is this characterisation correct, or is there some nuance missing here?
The thing that I'm finding a little hard to understand, is that these different variants of aircraft must have different handling characteristics, or different things to consider (ie. things unique to doing a longer flight), it does seem a bit crazy that no training would be required.
It also seems that the economic incentives are a bit backward - this kind of dynamic would stiffle aircraft innovation as a whole.


texts:
I have been confused about the relation of yaw and pitch in propeller powered aircraft. When such an aircraft is pitching up, will it yaw to the left or right? Conversely, when it's pitching down, which way will it yaw?

When I try this out on X-plane, the plane turns left when I take off. However, some online material insists that the plane will yaw to the right when I am pitching up. This is confusing me. What's the best explanation for this?


texts: Has anyone burned hydrogen in a gas turbine?

texts: I am just wondering if supplying compressed hydrogen to a gas turbine (combustor) would be a better fuel as it has three times the octane rating of kerosene. It just seems better all around.


texts: How should I request flight following when I'm not taking a direct route to my destination?

texts:
I want to plan a flight from KMSN - KDAY. My plan avoids the ORD airspace as much as possible, so something like:

KMSN - JVL - KARR - JOT - EON - KRZL - OKK - MIE - KDAY

What would be the phraseology to use to get VFR flight following to let ATC that I'm not planning the most direct route?


texts: What is the difference between "Land 2" and "Land 3" annunciations for Boeing autopilot systems?

texts: Another question's answers refer to certain Boeing jets having the capability to annunciate "Land 2" and "Land 3" when flying a coupled ILS approach. What does each of these modes require, and allow, beyond the basic coupled ILS? How are they different from one another?


texts: How to do blade element momentum theory analysis for different geometries of airfoil, e.g. NACA airfoils?

texts: I want to analyse NACA airfoils using BEMT. I have only yet done it for basic symmetric airfoils. I would like to know what all assumptions remain same in NACA airfoil analysis and to what degree it is accurate. Like for starters, will accounting for Cl-alpha change and geometrical changes in angle of attack be enough to analyse NACA airfoils?


texts: How does density altitude affect Taxi-Out Time?

texts:
To keep things brief, for a data exploration project, I calculated density altitude for a couple airports and used flight statistics from https://www.transtats.bts.gov/ONTIME/Departures.aspx.

I was under the assumption that a higher density altitude is bad for performance and would involve things like longer takeoff time which can prolong taxi out time(from gate to runway) since a plane in line would have to wait longer for earlier planes to takeoff. Is this true?

Or is there pretty much such a minuscule difference that density altitude shouldn't matter in the context of taxi out time?


texts: How come PSA airlines got the same IATA code as Comair?

texts:
PSA Airlines has the same IATA 2-letter code, "OH", as the now-defunct carrier Comair. Yet - the two companies are not related.

How is it, that IATA reassigned the same code to an unrelated carrier rather than assigning a new code? Are there any other cases of this happening?


texts: Is the term "guinea pig" defined in the Pilot/Controller Glossary?

texts:
Is the term "guinea pig" now or was it previously defined in the Pilot/Controller Glossary?

If it's not defined in the Pilot/Controller Glossary, maybe it's in some other publication.

I was flying with a crew member who used it while querying ATC about threading a hole in a line of weather. It went something like, "has anyone else guinea pigged that hole?" He said it was an actual controller term in their documentation.

I can't find it, but I was wondering if there was some kernel of truth to the statement.


texts: Why are Airbus captain control sticks placed on the left when most people are right-handed?

texts:
Why is it that control sticks for the captains on Airbus are placed on the left? Wouldn't it be uncomfortable considering that most of the people, and by consequence pilots, are right handed?

To my opinion this would make flying more difficult as a right handed person would have less sensitivity on his left hand.

(airbus.com)


texts: On how many routes an aircraft is used on a typical day?

texts:
I wonder how an commercial aircraft used to transport passengers is used on a typical day. I imagine several scenarii, but I cannot figure out if they are right:

take off in the morning from the company's hub to an airport and then get back and begin again all day long, possibly with a changing the crew when turning at the company's hub
from the company's hub, begin the day with a round trip to an airport A, then performing a round trip to from the hub to an airport B, and continuing with other airport until the end of the day
a triangular shape: a one-way leg from the hub to an airport A, then another leg from the airport A to an airport B, and then another from B to the hub, and continuing until the end of the day. A derivative could be the same with more airports (hub --> A --> B --> C --> D --> hub)
a long multi-leg route in one direction and then back (eg. A --> B --> C --> D --> C --> B --> A)


texts: Does the A380 have more than one auto-brake disengage switch?

texts:
I know that the A380 has low/med/high RTO auto-brakes. What I'm not sure about is if there's a switch near the thrust levers that can disengage the auto-brakes, other than the switches located on the brake panel.

To put it another way, the A380 has a brake panel where the switches allow you to engage/disengage auto-brakes (either low, med, or high RTO). But in addition to those, is there any other switch that can do the same thing without the pilot needing to take his eyes away from the view outside?


texts:
In India, during landing and takeoff the passangers are asked to open the windshield.
I googled the reason but couldn't find any technical logic.
I am also not sure if this practice is universal.
Can anyone explain reason.


texts: What causes the average speed difference between the JFK to DEN flights and the JFK to LAX flights?

texts:
I just realized shortest JFK - DEN flights are ~4h40m (280 min) and shortest JFK - LAX flights are ~6h (360 min). I'm talking about currently available commercial flights.

NY - DEN (straight line) distance is ~1625 mi, NY - LA distance is ~2450 mi (approximate measures using Google Maps' Measure Distance). So NY - DEN is about 0.663 of NY - LA distance-wise, while JFK- DEN flight takes about 0.777 of JFK - LAX flight time-wise.

In other words, going by distance, I would have expected JFK - DEN flight to be about 42 minutes shorter, or slightly under 4h. Any idea where the ~15% increase in flight time from what I expected comes from?