texts: What is the typical climb angle (versus the ground) of a single engine piston plane?

texts:
What are the normal climbing angles against ground on a SEP (single engine piston) plane and an airliner?

(no wing-air angles in here, but the climb angle when watched from the side of the plane)

(Source: user11961 - Own Work)


texts: How is a fly-by-wire system realized in big planes?

texts:
For example if whole system is build on CAN protocol that give maximum rate of 9000 messages per second with IMHO is quite low number for big plane.

Can you give me any example how this problem was solved?
Do they divide system into subsystem or use protocols like Ethernet IP?
Or maybe that number of messages is enough because they're sending only critical information?


texts: Large error and failing simulations for transonic compressible flow in simscale

texts:
I am trying to simulate flow over an object in simscale. For a compressible flow simuilation in transonic regions I am having trouble getting succesful and accurate solutiongs for the expected flow. Specifically, I am measuring "accuracy" as the expected stagnation pressure (the flow is over a pitot tube). There seems to be a diverging trend from the expected value (caculated from stagnation/dynamic pressure mach relation equation) as flow increases to transonic speeds. Eventually, around 0.8-0.9 Mach, the solution diverges.
Here is a link to my project (only compressible 9 is important ignore the other simulations)
https://www.simscale.com/projects/noahl310/compressible_with_varied_mach_testing_unblocked_pitot_tube/
Is there is anything I am doing wrong with my setup? or are there things I can change to get a better setup?


texts:
The center of pressure is:

A)The point at which the Total Aerodynamic Force acts
B)The point where the lift force acts
C)The point where the resistance force acts

Only one answer is correct,i think is B or A but the question is really strange.


texts: What does the term "loading" refers to when we talk about Blade loading and Stage loading in Turbomachinery?

texts:
I have been reading about the term Blade Loading and Stage loading in case of Axial Turbines and Compressors, however, I would like to know what does the term "loading" here exactly refers to?
What I also read was that if we increase the number of blades then the Blade loading for each blade will reduce but the friction and weight will increase, then what is the optimum number of blades one should have?


texts: What deviation from the official flight path is allowed during takeoff and landing?

texts:
Our local airport is currently going through CAP1616 and permanent airspace change consultations.

Considering take off and landing flight paths:

what degree of deviation is allowed from the official flight path by aircraft while under 7000 feet (2133 meters)?
what would be a typical distance travelled before reaching the aforementioned altitude?

A potential 3rd question relates to finding the designated flight paths but I believe this is answered in other questions.


texts: How much FOD hazard can a Styrofoam drink cup pose?

texts: So, the Collings Foundation and their touring warbirds were in town recently, and we went to visit them.  While out on the ramp though, my father managed to lose one of the Styrofoam coffee/drink cups the FBO provides (for their complimentary ice water and iced tea, of course).  How much FOD hazard could that runaway Styrofoam cup pose, considering its relative lack of hardness and stiffness/strength compared to most other FOD hazard items?


texts: Do all A320-family planes have leading edge high lift devices?

texts:
I keep seeing pictures of A320/321 planes with slats or some other form of leading edge high lift devices. However, on all my flights in the last years with A320s/321s I never noticed anything changing on the leading edge during approach (from my pax window point of view).

So my question is: Is that an option airlines can choose, if they want to have leading edge high lift devices? Or are they in all aircraft of the family? If so, are operators flexible in using them for approaches?


texts:
I have seen 2 rotor blades up to many and wonder when does having more rotor blades become less efficient? What helicopter has the most rotor blades?

Related: Why don't helicopters prefer shorter rotors with more blades?

What is the definining line between a helicopter and a drone a person can ride in?


texts: Does the APU consume a lot of fuel compared to a jet engine?

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


texts:
Why don't aircraft operates with IAS only?

Is there any other usage of Mach number except monitoring of shock waves formation?

How Mach number is calculated?


texts: Is turboshaft fuel efficiency affected by N2 loading?

texts: When using a free power turbine turboshaft, does fuel burn get affected by N2 loading? I am asking as I want to in the future bench test a turboshaft for fuel burn, but I don't know if the loading would affect the fuel burn.


texts: What would an all-flying aileron look like, and would it be a good idea?

texts: The only info I could find about someone doing this IRL was the British Army Aerorplane No. 1, but I don't think it ever flew with them. I don't know much about how this would affect the aerodynamics, but maybe it would give more roll? I'm not that experienced in aviation, could someone tell me the implications of this?


texts: What was the yearly number of MiG-15's produced?

texts:
Wikipedia's article on the MiG-15 only states a basic number of 12,000 produced natively, with up to 6,000 more produced in other countries. But it does not list any years for this.

When did mass-production start and end for the MiG-15 in the Soviet Union? This would at least let us divide 12,000 by the total years to get an average production rate. Ideally I'm looking for the number built each year, as this will surely vary year to year.


texts: In this question about aircraft dumping fuel I was told that there may possible be guidance in the QRH.  I know that there are a lot of guidelines given to pilots, but I've never heard of this one.  Would anyone care to explain, from a pilots perspective, what exactly a QRH is and how it's used in modern aircraft operation?


texts: What is the relationship between aspect ratio and divergence speed?

texts: Why do longer wings with higher aspect ratios have lower divergence speeds?


texts: Are the firewall and forward pressure bulkhead different components?

texts: Suppose in a single engine aircraft, where the engine is located near the nose of the aircraft. If the cabin is pressurized, I know there will be a requirement of pressure bulkheads, both in the rear and the front to prevent the excess pressure from leaking out (and bearing the pressurization stresses). Now my question is that is the firewall, which is used to keep the heat of the engine (and flames if the engine ignites) away from other components of the aircraft, same as the forward pressure bulkhead i.e. does the firewall in this case have 2 roles: being heat resistant and at the same time bearing the pressurization stresses due to excess pressure inside the cabin.


texts: How to interpret 14 CFR Part 61 Requirements 61.129 on instrument training time?

texts:
For part (3)

  (i) - Ten hours of instrument training using a view-limiting device including attitude instrument flying, partial panel skills, recovery from unusual flight attitudes, and intercepting and tracking navigational systems. Five hours of the 10 hours required on instrument training must be in a single engine airplane;

Can this time be previous instrument time, or does it have to be specific to the commercial certificate?

Same thing with the night take off and landings at a towered airport.

  (4)(ii) 5 hours in night VFR conditions with 10 takeoffs and 10 landings (with each landing involving a flight in the traffic pattern) at an airport with an operating control tower.


texts: Can an aircraft (civilian or military) land with its brakes already engaged?

texts: Can an aircraft land with its brakes already engaged at the max landing speed of that aircraft?


texts: Have there ever been any JATO bottles using only kerosene?

texts:
I've been reading about the early rocket work during WW2. They tried all sorts of fuels, hydrogen peroxide, hydrazine, red fuming nitric acid...

Just in the scope of JATO/RATO, has there ever been one working just with kerosene? The airplane would accelerate normally to sufficient airspeed such that enough oxygen was flowing, then the JATO would ignite. This would then boost the aircraft very rapidly up to a high altitude.

I think this could be called an afterburner all by itself (without the turbojet lol), or maybe even a ramjet all by itself. Whatever you call it, it has no moving parts other than a fuel pump. So I am wondering if this concept was ever tried during WW2 or shortly thereafter.

(P.S., surprised there is not JATO tag, nor RATO tag. I will create it but also use "takeoff" for visibility purposes.)


texts: Diamond DA42 - Do you need the electric master on to extend landing gear?

texts:
For the Diamond DA42 (TDI)
Learning my electric fire emergencies. Would it be wise to extend the landing gear before electric master is turned off?
Does the (hydraulic) gear power pack require the electric master to be on to extend the gear?
I presume if the electric master is switched off, could still extend manually using emergency gear extend lever?


texts: Are there advantages when operating with CG near forward or aft limits?

texts:
If the center of gravity of an airplane is too far aft, it will become more unstable

Iif the CG is too far forward, then drag will increase due to increased angle of attack.

But what are the benefits to operating with the CG near the aft, or forward, CG limits? In what situations would one choose to do so?


texts: Is there a minimum distance between a runway and a public road?

texts:
Does the FAA require a minimum distance the between the TDZ of a runway and a public road?

The reason I ask is because an aircraft landing at a small GA airport (Garnett Municipal, K68) came across the roadway I was driving on low enough that if I'd been 200 yards up the road he'd have hit my truck. Or at least he'd have had to go around.

From the satellite pic you can see that the end of the runway is about 30 feet from the road. The TDZ is about 150 feet. A 3° approach would put you just short of 8' AGL at the road, which is just about exactly how high he was. My truck has a clearance of 10', so it's quite possible to strike vehicles on the road if one is too focused on the runway.

Although it's not a highway (that's about 1000' from the runway), it's the only paved road going east/west for several miles so it gets a bit of traffic

Is it common to put a runway so close to a road?


texts: Does the Reynolds number on a smaller model need to match the one of the original aircraft?

texts:
1.Airbus 380-800 :
The overall length of it , is 72.72 m and its cruise speed is 903 km/h. Based on the mean chord of wing , its Reynolds number in cruise phase is around 75 millions. Now , a 1/18 scaled model is built for the purpose of wind tunnel testing. Assuming similar flow condition , the Reynolds number of wind tunnel  tests would be around 4.15 millions. This is great difference. Is Reynolds number , as a very important  similarity variable, is so different for wind tunnel testing comparison  with free flight condition, what is the advantage of performing such tests?
2.do we always need to match Reynolds number exactly?


texts: Why is the aerodynamic center for most airfoils located at the quarter chord location?

texts:
I've been reading several sources on the location of the aerodynamic center

https://web.mit.edu/16.unified/www/FALL/fluids/Lectures/f03.pdf
https://en.wikipedia.org/wiki/Aerodynamic_center
John Anderson Jr., Fundamentals of aerodynamics

Many (such as for example Wikipedia) determine the aerodynamic center by writing out the equation for the moment for an arbitrary point, and then apply some definitions to get to the end result: the aerodynamic center lies at the quarter chord, see below:

However, I'm looking for a more physically intuitive explanation, probably starting from thin airfoil theory. The way I understand it, ultimately the aerodynamic center is determined by how the distribution of lift changes with angle of attack.  Thus, the distance the center of lift moves w.r.t. the aerodynamic center cancels out the resulting moment due to the change in lift with angle in attack.
Can we explain why this point ends up to be at the quarter chord location?


texts: How close can planes fly to each other over the ocean?

texts:
While on a recent Air Transat flight from Toronto Pearson to London Gatwick, several hours into the flight and over the Atlantic Ocean, my daughter and I noticed a plane behind ours to the left, flying quite close. Assuming there must be protocol for how close planes can fly to each other, I was more interested than concerned.

It then became apparent that the other plane was flying faster than our plane and coming closer. The plane came close enough for my daughter and me to see all the windows as its path led it to cross in front of our plane. It was only very slightly higher than our plane by mere meters. As it very quickly approached us we lost sight of it as it crossed in front of our path.

My daughter and I figured a crash was imminent. Our plane then altered its path, moving slightly down and to the right.

This was an overnight flight and at the time the cabin lights were turned down and the passengers sleeping. There was no flight crew to speak with at the time and we didn't want to disturb anyone considering we were... well.. still alive.

Upon return from our trip I called Air Transat and spoke with Customer Relations who had the flight records pulled. There was no report of the incident. I cannot believe any regulation could possibly allow for two planes to fly so close to one another under any circumstances. I need to understand what happened here, the distance planes must remain from one another and why such an occurrence would not be logged.

The plane was not marked. It was not a Lear jet but a small, dark, unmarked passenger plane. Thank you for your help. Obviously I am still very disturbed by this event.


texts: Are there limitations on taking off or landing if airport lighting such as the VGSI (PAPI) is out of service?

texts:
There are many types of airport lighting that aid pilot to land safely such as ALS, VGSI or runway lights. And some instrument approach procedures state that their weather minimums must be raised in case the ALS is out of service.

However, I think those aeronautical lights are not essential for pilots, they're just aids. In case the airport lighting such as VGSI (PAPI) is out of service, are there limitations for landing or take-off?


texts: Does the FAA have a document that details each step found in a Component Maintenance Manual?

texts:
Is there a standard FAA document type for 'general' maintenance steps that a Component Maintenance Manual (CMM) can reference?

For example:

  Once the bulb has been locked into the socket, reference the bulb
  cleaning section in Document XYZ for the complete bulb cleaning
  procedure.

Where can I find Document XYZ?


texts: Why are some engine nacelles thicker than others?

texts:
Why are the engine pods on the Embraer 190 thicker, related to the overall diameter of the engine, than most of the other pods on other jets? Wouldn't this design add more drag and reduce efficiency?

Pictures added for reference.

Embraer 190:

Boeing 737:

Airbus A330


texts: What are these holes at the right front of the ATR72?

texts:
The ATR-72 has these 3 holes at the right front of the fuselage. They are marked as Captain, F/O and StandBy. It says do not obstruct, and the area inside the red lines must be smooth and clean.
What are these for?


texts: Are there any helicopters equipped with pressurized cabins?

texts: I would think that a pressurized helicopter is impractical since helicopters are usually flying at low altitude, but has a pressurized helicopter ever been conceived or built?


texts: What does the “nose-high” product of inertia represent?

texts:
I am reading this slide:

Source: http://www.stengel.mycpanel.princeton.edu/MAE331Lecture10.pdf

Is Izx always considered small and we can assume it is 0, as many texts assume?

I need to make this clear:
This is the body axis:

I assume that G is the center of mass, GZX is the symmetry plane. So  Iyz = Iyx = 0. But why is Ixz zero? Do they rotate the body coordinate system around Y axis so that Ixz = 0?


texts: What does it mean for a door to be armed?

texts: What does "arming a door" mean?  Is the orange tape that's applied over a window related, perhaps as an indicator to people outside that the door is armed?


texts: Why was the 307’s pressurisation system removed when it was modified into the C-75, despite the fuel-burn advantage of higher-altitude flight?

texts:
The Boeing 307, an airliner derivative of the B-17 heavy bomber, was the first pressurised airliner to enter series production and go into service (hence its bulbous, altogether un-B-17-like fuselage, the better to hold pressure), allowing it to cruise at higher altitudes,1 where the air is thinner and less draggy, without incapacitating its occupants.  As World War II broke out shortly after the 307 was introduced, only ten ended up being produced (out of which only nine still existed, the first off the line having already been destroyed in a crash), and eight of the nine surviving 307s were drafted into military service;2 Pan Am’s fleet of three flew military contract flights in Latin America and the Caribbean, while TWA’s five 307s were extensively modified for transatlantic VIP and freight carriage (being redesignated as the C-75).

One of the modifications applied to the ex-TWA aircraft3 was the removal of their pressurisation system, ostensibly to save weight; this restricted the C-75s to an altitude safe for unpressurised human beans (approximately 8 kilofeet or so max, as opposed to the 12 kft of the pressurised 307), with resultant drag and fuel-burn penalties in the denser, lower-altitude air (one of the other modifications was the installation of numerous additional fuel tanks to sustain the aircraft across the Atlantic).

This does not seem to make sense, given that the main advantage of cabin pressurisation is the aforementioned ability to fly at higher, less-draggy altitudes, where an aircraft cruises at a (sometimes much) higher true airspeed and burns less fuel, allowing it to carry more paying payload and not as much fuel.4  Thus, even a relatively-low-ceilinged aircraft like the 307 should still have been able to carry more payload, or carry the same amount of payload farther, when pressurised than when unpressurised, even factoring in the extra weight of the pressurisation system, due to the lesser fuel requirements of (and, thus, lighter fuel load needed for) flight at pressurisation-enabled higher altitudes - so why did the USAAF remove the 307s’ pressurisation equipment?

1: Albeit not that much higher, due to its low fuselage pressure rating and its lack of a passenger emergency oxygen system.

2: The remaining 307 (the second one off the production line) was Howard Hughes's personal airplane (he hardly ever used it, though).

3: Which would be returned to TWA at the end of the war, and converted back to commercial passenger configuration (with a number of improvements gleaned from wartime B-17 work).

4: Contrary to what those less-well-informed about aviation tend to believe, the purpose of cabin pressurisation is not to allow airliners to fly above bad weather; even modern jetliners, which can cruise at up to FL410 (~41 kft), don’t fly high enough for that.  You’d have to go up to at least about FL550-FL600 (~55-60 kft) to overtop storm clouds, something of which only one airliner ever produced was capable (and said airliner has now been out of service for over a decade and a half).


texts: How is a confusion possible between Western and Russian Attitude Indicators?

texts:
Yesterday I watched a documentary on Crossair Flight 498 accident. One of the factors that might have contributed to the accident was the confusion of the pilot on interpreting the attitude indicator; he was initially trained with Russian model (right) instead of Western model (left):

But looking at both type of indicators, could anybody tell how the confusion is possible? In both models, if you see the indicators turning your head right (as if you were sat on the plane's seat), both show that the right wing is "touching" ground. That means that you are clearly rolling right. How can a pilot interpret that the plane is rolling left?


texts: Why are manufacturers assumed to be responsible in case of a crash?

texts:
I attended at a training concerning airborne software and the coach remarked that despite at the normal courts, when an aircraft crashes and the authority investigates, a manufacturer is guilty for that accident until innocence is proven that the manufactured device did not produce the defect causing the crash.
I hoped to find on the web some reference to this "guilty until proved innocent" rule, but I cannot. Do you know where I could find some info about that?


texts: Are there any new orders for the B747 passenger version?

texts:
I was reading an article about the shortcoming and decline in the use of the A380, based on the modification of the model to move people, and there is a comment saying that both the 380 and 747 are already halting production, and the only one surviving is the 747-8 in freighter mode.

Also I didn't performed an extensive search, but I can't find orders later than 2018.

Does this mean no one is operating the 747-8 in passenger flights anymore?


texts: How does the safety record of a Cessna 152 compare to a jetliner in Europe?

texts:
I have a fear of flight and I'm working on it.

There is an airfield about 40 minutes from me and they offer flying lessons in a Cessna-152 for around 140 euros per hour. Pretty reasonable I think. So, this is my next step. But... I've only ever flown in an A320 / 737. This is because of the (approximate) very low risk of around 1 in 11 million of a fatal incident occurring.

My question is, what is the fatality rate (per million) for flights in a Cessna? I know it will be higher, I just want to know how much.

I did Google and look around, but the stats seem skewed on several sites as they include global incidents, whereas I know Europe is more tightly regulated than some parts of the world. Also, I'm not going to be performing (intentional) aerobatics, so I think we can exclude those cases as well.


texts: Are mode C altitude returns valid for aircraft separation?

texts:
According to FAA JO 7110.65 5-12-8 'Validation of MODE C READOUT', Mode C is valid if there is less than 300 feet deviation from the pilot reported altitude.
If ATC instruct 'A' aircraft to maintain 5,000ft, and its Mode C indicate 4,900ft on radar, and ATC instruct 'B' aircraft to maintain 6,000ft and its Mode C indicate 6,000ft, are A and B vertically separated?
By looking radar, it is 900 feet separation, but pilot reported altitude is 1,000 feet separated.


texts: Why do some aircraft have multiple switches for the landing lights?

texts: A question just popped into my mind: Why does an A320 overhead panel have 2 landing lights switches? What's the logic behind that? Why isn’t there only a single switch to turn on both landing lights?


texts: How do aircraft stall warning systems handle (or not) asymmetric-stall situations?

texts:
Most, if not all, new airplanes are required to have stall warning systems to (as the name should make clear) provide the pilots with a warning when the airplane is about to stall.  Most stall warning systems work not by directly detecting the rapid increase in airflow separation near the stall point, but, rather, by measuring the airplane’s angle of attack and giving an alarm if it is greater than some threshold value.  However, as the attack angle at which the wing stalls can vary by a great deal, these older stall warning systems have multiple thresholds; for instance, a particular system might sound an alarm at 15º in a clean configuration, but lower the threshold to just 5º if icing is detected (as icing promotes airflow separation, and, thus, lowers the wing’s stall angle), while waiting until 30º if the slats are extended (as leading-edge devices, such as slats, delay airflow separation, and, thus, increase the allowable attack angle).

With all this in mind, how do stall warning systems handle situations in which one wing is stalled, or close to stalling, but the other wing is not?

I can think of a number of scenarios under which this might occur:

Category 1 - The two wings have different stall angles, such as could result from...

Scenario 1: ...asymmetrical icing, or damage to the leading edge of one wing but not the other, which would increase the roughness of the damaged or more-iced wing, thereby increasing the tendency for the airflow to separate from said wing, and, therefore, cause it to stall at a lower attack angle than the undamaged or less-iced wing.
Scenario 2: ...asymmetrical leading-edge device (non)deployment, such as from failure during takeoff of the hydraulic system powering one wing’s outboard slats, resulting in the retraction of said slats, which would decrease the stall angle of the wing with non-extended or less-extended leading-edge devices.

Category 2 - The two wings are at different angles of attack relative to the airflow around them, such as could result from...

Scenario 3: ...violent, fine-grained turbulence, which could result in the airspeed of one wing being considerably lower than that of the other wing, thereby causing the horizontal component of the airflow around that wing to be considerably decreased while leaving the vertical component of said airflow unchanged, thus resulting in the lower-airspeed wing encountering the oncoming air at a much steeper angle than the higher-airspeed wing, and, as a result, possibly causing the lower-airspeed wing, but not the higher-airspeed wing, to exceed its stall angle; for instance, if an airplane is flying at an indicated airspeed 30 knots above its stall speed, and is hit by an asymmetric gust that causes the left wing to experience a 45-knot tailwind while the right wing sees a 15-knot headwind, the left wing will be 15 knots below its stall speed at the same time as the right wing is 45 knots above its stall speed, and, therefore, the left wing will stall, but not the right wing.
Scenario 4: ...a rapid yaw to one side, possibly as a result of overenthusiastic piloting or a mechanical failure, causing the airspeed of one wing to increase and that of the other to decrease, possibly causing an asymmetric stall via the same mechanism as in scenario 3 (for instance, a sudden rudder hardover would produce an extremely high yaw rate, and, thus, airspeed differential, before the pilot(s) had time to react, which could easily bring one wing, but not the other, below its stall speed).


texts: Are there any cameras inside a plane to watch out the activities of passengers?


texts:
I hear a lot about CRM these days (it seems to be a buzz word). It is related to safety, but what exactly is it?

From what I know, it also applies to single pilot flights (even in a Cessna 150!), but where is the "crew" that is being managed in this case and how does it improve safety?


texts: How much does it cost to lease a jetliner?

texts:
As the title says, how much would it cost to lease a airplane for an airline. Let's say a B737 and a B747 or similar aircraft.

I tried to contact several aircraft leasing companies but so far I've been ignored, and searching this site hasn't resulted in any answers either.


texts: Why is the ISOLATION VAVLE switched to OPEN during ENGINE START on Boeing 737?

texts:
As the SOP says in Preflight Procedure – First Officer:
"ISOLATION VALVE switch – OPEN"
In this way, when engine starts, the ISOLATION VALVE is OPEN not AUTO.
The PACK valve is switched to OFF, under AUTO can also make the ISOLATION VALVE open.
SO why is the ISOLATION VAVLE switched to OPEN instead of AUTO?


texts: In a hydrogen fueled plane, could part of the fuel load be allowed to become lighter than air to offset or trim for the load?

texts:
This is inspired by How can adverse maneuverability due to a fuel tank behind the rear pressure bulkhead be mitigated in Airbus ZeroE hydrogen plane? .
I was thinking, with the cryogenically stored hydrogen (and required equipment) being heavy and so far away from the centre of lift of the craft in Airbus's design, it might be possible to trim the aircraft by releasing some of the hydrogen into a chamber where it can be lighter than air, reducing the nett weight of the tail, rather than trimming aerodynamically or with a movable weight.
I'm not good enough to do the math, but I suspect the size of the chamber would have to be colossal to make enough of a difference to matter - with the added bonus of being essentially an explosion waiting to happen.
Would there be a sweet spot for the average temperature of the stored hydrogen that balances the weight (including weight of corresponding equipment) against the volume of fuel stored, or is it going to be a case of coldest/most dense is the most efficient and trim needs to occur the traditional way?


texts: Why does a turn and slip indicator matter?

texts:
I'm studying the principles of flight, and I'm having some unanswered questions in my mind regarding the turn and slip indicator.

I'm reading that a turn and slip indicator displays the slip or skid of the turn. It probably has something to do with directional stability.

But the questions I'm having are:

Why does it matter if the airplane is in a skidding or slipping turn?
What are the consequences of skidding or slipping turn?
Is it dangerous to be in a skid or slip?
Why would a pilot would like and/or not like to be in a skid or slip?


texts: Can anyone identify this old airplane, and/or what era it's likely to be from? The photo is from northern Italy, and it's the only photo I have. I'd be very grateful for the help!


texts: What determines the touchdown zone and aiming point markings on a runway?

texts:
Large runways usually have a marked touchdown zone, and a marked aiming point (with two giant bars in the US). How is that location chosen? It seems like it is frequently further down the runway than I would have thought maximized available runway length.

How important is it for an airliner to land on that spot? Are there regulations about this?


texts: Is the "auto-routing" created by online flight planning resources preferred by ATC over Direct routing when NO preferred route exists?

texts:
I noticed that when I use online flight planning resources, they provide an "auto-routing" option for my flight. I also noticed that they are the same between both services so it seems like both are pulling the route from somewhere. Additionally, the auto-route appears to be different than a "preferred route" because, for example fltplan.com will say "No Preferred Routes or Stored Routes" then it gives me (a sometimes crazy) auto-route.

Are auto-routes predetermined or is it just an algorithm (i.e. nearest intersection/victor airways to destination)?

Extra Credit Question: If there is no preferred route for a given destination, is filing Direct or using the auto-route more likely to get you a "cleared as filed?"


texts:
Diamond DA-40 NG Manual did say that to use Auto Diesel (EN590), OAM 40-370 must be installed. Does anybody know or have experience on this OAM 40-370 requirement?
I cannot find this document on the Diamond Website


texts: What is this jetliner seen in the Falcon Crest TV series?

texts: I'm trying to identify this jetliner from the "Falcon Crest" TV series filmed in 1984  It's from episode # 068 <3.28> "Ashes to Ashes".  This is the only scene featuring the plane. There are other scenes with planes (stock footage) in this episode, but they feature different jetliners, which have been identified already.  Unfortunately, there's no shot of the cockpit and tail available.  Does anyone recognize this make and model, please?


texts: Is the "wing area" of a biplane the projected area or the total area?

texts: When you specify the wing area of a biplane, do you specify the planform area (the projected area) or do you specify the effective area of both the wings?


texts: Why is it not a good idea to climb higher than a level at which you would have a cruise weight-climb speed less than 500 ft/min?

texts: In relation with What is weight-climb speed?, why is it not a good idea to climb higher than a level at which you would have a cruise weight-climb speed less than 500 ft/min?


texts: If operating an ultralight with private pilot certificate, which rules apply?

texts:
If a holder of a private, commercial, or ATP pilot certificate operates an ultralight aircraft; and that aircraft is also equipped with the radios and transponders required by an airspace for GA aircraft, can this flight operate under standard VFR rules as a GA aircraft rather than operating under ultralight rules? (ie. Using non-towered airports which are marked "ultralights prohibited" in the chart supplement, and controlled airspace airports.)
All of the regulation of airspace that I can find is focused on either the pilot's certificate and rating, or the aircraft equipment, rather than the aircraft category and class. That is a slow "experimental" light-sport STOL bush plane (which could be as slow as an ultralight), a C172, or a King Air 250 are all equally allowed into class E, D, C, or B airports as long as they have the required electronics and a PIC with a private pilot certificate or above.
I ask mainly because I would like to use an ultralight for commuting, and the places I commute are airports of the above nature. (local street traffic is terrible, and I need STOL capability for my home field. Less than 700ft to clear a 50ft obstacle.)


texts: What is needed to certify an aerodrome as an airport in Canada?

texts:
So here.
All airports are aerodromes. All aerodromes are not airports.
Difference between Airport and Aerodrome:

An aerodrome or airdrome is any place from where flight operations can take place. This can include an airstrip in the middle of nowhere to a commercial airport in the biggest city in the world. An airport is a special type of aerodrome that has satisfied certain certification criteria or regulatory requirements of the ICAO that a regular aerodrome may not have achieved.
The term airport implies a certain stature of having satisfied certain certification criteria or regulatory requirements of the ICAO that a regular aerodrome may not have achieved. Hence it can be said that all airports are aerodromes, but not all aerodromes are airports.

So then what facilities and services does an aerodrome need to have, in order to be certified as an airport in Canada?


texts: How to improve engine-out handling on a multi-engined aircraft?

texts:
Hypothetically, if I wanted to create a multi-engine airplane with the best single-engine handling characteristics/lowest Vmc, would moving the vertical stabilizer far back be beneficial (even if it looked weird)?

My school of thought is that: At low airspeeds, the rudder is less effective. If I can't increase the amount of airflow over the rudder, will giving the rudder a massive arm allow the plane to have more directional control at lower airspeeds with the increased torque?


texts: Why do UCAV/UAV designs mostly use lambda wings instead of pure delta wings?

texts:
Why do recent UCAV/UAV designs mostly use lambda wings (such as Taranis and Dassault nEUROn) instead of pure delta/diamond wings (such as X-47A Pegasus and Lockheed D-21)?

As for stealth characteristics, both wings have a direct advantage in radar wave reflection.

The image was taken from Technology challenges of stealth Unmanned Combat Aerial Vehicles (Sepulveda & Smith, 2017).


texts: When does the ATC assign runways to aircraft arriving at an airport?

texts: I want to know how far from the airport runways are assigned. Approximately how many nautical miles away or typically how many minutes before landing would the pilot know which runway they'd be landing on? I am specifically interested in large busy airports like DFW, ATL, ORD, etc. Does it vary a lot based on weather and traffic conditions?


texts:
What are the requirements to become a language proficiency examiner? Does the person have to be a pilot? Does it have to be a flight instructor?

What kind of language proficiency rating do they have to hold to test level 4 / 5 / 6? I guess they have to have 5 to test 4 and 6 to test 5 and 6, is that true?


texts: Would one expect Canadair CL-215 or CL-415 planes to be equipped with a working ADS-B transpoder?

texts:
In a forrest fire in Greece, on which according to news sources eight such planes are operating as firefighters, no planes can be seen on Flightradar24.  Only a fire service's helicopter can be seen flying around.
Note that the planes in question are operated by the Hellenic Air Force.


texts: How does one determine runway orientation without a local wind rose?

texts:
We are planning to establish new airport, but then we have no wind rose analysis of the location.

How can we predict what's the right orientation for the runway that satisfies the 95.


texts: Why might a too-wide runway be a problem?

texts:
In the September 2020 issue of EAA's Sport Aviation, Budd Davisson writes

Runway width becomes a problem for some taildraggers when it gets to be less than 35-40 feet because of the lack of visibility.

Sure.  When you can't see the centerline, it's nice to have some lateral margin of error.
But later in the article (p. 74) in the caption of an overhead photo of a small airplane on a runway seven times wider than its wingspan, he writes

Oddly enough, super-wide runways can cause as many problems as very narrow ones, especially for taildraggers.

What might such problems be?  (Not wandering into the grass.  Even if you can neither look over the nose nor locate the runway's edges, if during takeoff or rollout you drift to one side, wouldn't you still notice the center stripe or the edge or the lights in time to correct?)
Do any NTSB reports mention a too-wide runway as the cause of an incident?


texts: Are Uber Elevate and other air taxis subject to domestic ownership and control rules?

texts:
When Virgin Airlines USA was being established, the company was forced to restructure due to a determination that effective ownership and control was held by Richard Branson's Virgin Group, a non-US entity. These rules are widely criticized in many countries, but existing carriers like the reduced competition they provide and lobby to keep them in place.

Uber plans an air taxi service and has recently sold a significant share to Softbank, a Japanese company (Fortune). Uber as a ride hailing service has worked around many conventional taxi regulations, but as it gets into air taxis it will be up against the US Department of Transportation which is not so easy to push around. If Elevate is considered an air taxi it will have to respect air taxi rules.

Are US air taxi companies subject to domestic ownership and control rules just as domestic airlines are?


texts: How is structural damage to a composite fuselage detected?

texts:
When a service vehicle collides with the aircraft, the plastic nature could hide any subsurface fractures which could propagate as the aircraft goes through cycles.

How is potential damage diagnosed on the A350 or 787?


texts: How to disable GPWS in a 737NG just like how the Airbus can?

texts: The Airbus planes have a feature where the GPWS can be disabled. But I cannot find any switch in the 737NG cockpit to disable the GPWS.


texts: What is the difference between IMU (Inertial Measurement Unit) and AHRS (Attitude and Heading Reference System)?

texts:
According to online sources like wikipedia the difference belies on the addition of an on-board processing system (I assume it means a microcontroller) which outputs already processed data and not simply the raw measures of the different sensors.

However I would appreciate the take on this of someone who has experience on the subject, a more practical standpoint.


texts: Do turbofan engine cowlings dilate during spool-up?

texts:
I was watching this Youtube video, portraying a Fokker 70 taking off. I wouldn't have noticed if it weren't for a comment, but during spool up (~ 3:24 in the video), it appears as if the engine cowling is dilating. (See image below, if you don't want to watch the video). According to the person who left the comment, this is due to the pressure changing.

I'm having real trouble accepting this — though I do see it with my own eyes, I'm finding it more intuitive to believe something else is going on (I would think something related to the camera, though it seems to be well secured and I can't see any other perspective change).

In the end, since intuition is a poor tool for discovering the truth, I decided to ask:

Do turbofan engine cowlings really dilate due to spooling up, and is it really because of pressure difference? And is it the whole cowling or only the inlet that dilates?


texts: Why did this A320 stall protection demo not hold Valpha max?

texts:
This video is about the Airbus A320 High angle of attack protection

At 4:54 - 5:13 why did it pitch down? I know it is  trying to maintain Valpha max but if it would have stopped following Valpha max it was at around 200 knots and could have kept climbing at a very good rate. Instead it maintained Valpha max but when it maintained Valpha max the speed decreased and and it pitched down and thus the vertical feet per minute started to decrease.

I thought it was suppose to maintain the highest possible lift and if it stayed at 200 knots with the pitch up the aircraft was climbing at a very high rate but it pitched down and slowed the aircraft so it wasn't climbing at its max performance.


texts: How long will one remain conscious in the event of a sudden cabin depressurization?

texts:
I know the usual scenario is where an airliner suffers from an explosive decompression and the oxygen masks drop and the plane descends to a safer altitude but.....

This is a purely hypothetical situation but if a passenger plane was cruising at 39000ft+ and it suffered a cabin leak that somehow went unnoticed by the crew and passengers and the oxygen masks didn't drop, how long roughly would it be before the passengers were incapacitated, and how long before the lack of oxygen became fatal.


texts: What areas of a commercial airliner are pressurized besides the cabin?

texts: For example, what about the baggage compartment? Landing gear housing? Avionics?


texts: Is there any reason in principle that large aircraft couldn't be converted to be controlled remotely?

texts:
Suppose the pilot or pilots of a plane become incapacitated for whatever reason. At the moment, there is nothing that can be done from the outside to stop it other than to shoot it down (am I right?).

Would it in theory be possible that planes have a 'safe landing' program built in that, at a signal from the ground takes over control? It then does everything necessary to land correctly and automatically at a nearby airport.

I realise I am making a lot of assumptions here. My main question is not about the logistics  of what would have to happen on the ground, nor is it about whether a new generation of terrorists could hack into such a system for their own purposes. It is about how easily current autopilots could be adapted to have a 'land safely' option. What modifications would the manufacturers have to install within the plane itself that would make this possible?

Summary

Is it true that currently, the only way to control a runaway aircraft is to shoot it down?
In theory could an existing autopilot have a simple interface that is retrofitted such that a single signal from the ground  sets it in 'return to base' mode and produces a safe landing?


texts: What did Paris' de Gaulle airport look like before the t2 expansion?

texts:
Charles de Gaulle airport (CDG/LFPG) in Paris had great expansion in the new century, including new runways and terminal 2 buildings.

What was the airport layout before the great expansion?


texts: What to do when you accidentally land on a runway thats borderline long enough to land on?

texts:
I was reading another question earlier when I noticed a story about a 737-700 that landed at M. Graham Clark Downtown Airport in downtown Branson Missouri.  The runway is only 3738 ft, long, which is a bit short for that particular kind of aircraft.

Apparently the pilots set the aircraft down hard and immediately did everything in their power to bring the craft to a halt, stopping about 500ft short of the far end of the runway (which, btw, ends in a cliff.  Just to heighten the suspense).

I'm sure they had their reason, so I'm not going to question them.  I just wanted to use it as a set up for this question:

If you accidentally touch down on a runway that is borderline long enough to stop your aircraft on, how would you determine if you wanted to either stop or just do a touch and go?  Is it too late once you've already touched the ground?


texts: How far from a taxiway, can a walking or biking trail be built?

texts: How far from a small single runway airport's taxiway, can something like a walking or biking trail be built?


texts: Can any US airline fly to and from any US city it wants to?

texts: I am trying to understand the US commercial aviation industry. Assuming that slots are available, are US airlines permitted to fly to and from any US city they want to? Or are there limited permits issued by each city/state that limits the number of airlines that can serve an airport/city/state? For example, if I start an airline based in New York, is it simple to get permission to fly between San Francisco and Anchorage (assume that slots are available)? Were there any restrictions before the Airline Deregulation Act of 1978?


texts: Did Boeing really use ferrets to run wires through aircraft during construction?

texts:
I've seen many articles on the internet (here, here & here) claiming that Boeing used a team of ferrets to run cables through hard to reach areas when building aeroplanes, but I've never seen any official sources to back these claims.

Is there any truth to this, or are they just baseless internet rumours?


texts: Do any airports have runways or taxiways that cross active rail lines at grade?

texts: Gibraltar has a runway which crosses an active road at grade (which, due to the peninsula’s geography and the resulting constraints on the airport’s location, happens to be the main road connecting Spain and Gibraltar, thus bringing traffic between the two to a halt whenever the runway is in use), which got me wondering: are there any airports with runways (or, for that matter, taxiways) which have grade crossings with active railroad lines?


texts: Will flying cars fall under aviation regulations?

texts: As science and engineering keep inventing new technologies like flying cars http://www.iflscience.com/technology/are-flying-cars-finally-becoming-reality, air space may become heavily overcrowded. Will flying cars be considered "aviation" or are there (will there be) some rules like flying with particular altitude will be considered as aviation? (As the concept is becoming reality soon or later it has to be decided.)


texts: What are Operations Specifications (OpSpecs)?

texts:
I had never really heard of OpSpecs until I started a new flying job that was at a Part 135 company.

So for those people who are new to this (or are just interested):

What is an Operation Specification and how does it relate to the actual CFR regulations?
What kinds of things are they used for?
Who uses OpSpecs?
In general terms, how is an OpSpec obtained?


texts: Are tripropellant jet engines a viable way to increase fuel efficiency for large commercial airplanes?

texts:
I was just reading about a tripropellent rocket engine that apparently passed all tests and was ready for flight before the program was cancelled in the early 90's. The engine was the RD-701 for the MAKS spaceplane program. It used kerosene and liquid oxygen before switching to liquid hydrogen.
So I'm now thinking about tripropellant jet engines. If we had a small tank of liquid hydrogen to either mix with the regular jet fuel or replace it for a short while, would this viably improve fuel economy for large commercial airplanes?
(I've heard that jet engines can easily run on almost anything that burns, so presumably it would be easy to get a jet running on hydrogen. Correct me if I'm wrong.)
There are many types of efficiencies, so let me be clear about which one I'm interested in: Fuel economy, as in miles per passenger-gallon.
Let's ignore any logistics on the ground about obtaining and storing the hydrogen. However, storage aboard the airplane itself should certainly be considered and might be a very detrimental factor, as might flammability. I'm pretty sure we would at least need double-walled, vacuum insulated tanks to let us store that hydrogen throughout the flight. They might be twice as heavy as normal tanks.
If you know anything about hydrogen, its chemical energy (per mass) is greater than gasoline....by a factor of 3 IIRC. The Lower Heating Values are around 120 versus 40. So we might all ask why not just use liquid hydrogen in everything and what is taking so long? Well apart from cryogenic considerations, it's not very dense at all. We would need a huge tank maybe even bigger than the airplane itself to store the necessary hydrogen, even tho that huge volume of hydrogen would still weigh less than the necessary jet fuel.
I think the idea of tripropellant engines is to allow some hydrogen with a not-so-overwhelming tank. The tank would only be as big as we can reasonably handle. Therefore we use some hydrogen to get a bonus in fuel economy.
P.S. I'm not really asking this from a "green" perspective. Hydrogen and oxygen burn to form pure water exhaust, which sounds so harmless, but water vapor is actually a very potent greenhouse gas, much more potent than CO2 molecule-for-molecule---especially when released at high altitudes. I'm asking this purely from a fuel-economy standpoint.


texts: What are these sensors on the Night Stalkers' Chinook MH-47G?

texts:
What are these sensors (or lights) on this heavy assault Chinook MH-47G of the US 160th Special Operations Aviation Regiment, "Night Stalkers"?

Source, picture by Russell Hill

This regiment was the subject of Ridley Scott's Black Hawk Down.


texts: Where can I get a high-res photo of the RAT from an A320 Airbus?

texts: I'm working on a project regarding the hydraulics system of the A320 airbus.  I can't seem to find a clear Hi-resolution image of a grounded A320 with the RAT extended out.  Anyone know where I can find one? Or if you have one and don't mind me using it for my project, I'd be much obliged!! Thank you!


texts: Is the ground clearance of the B737 engine low compared to similar aircraft?

texts:
I'm referring to this other Question.
I want to know more about the B737 and the distance between the engine and the tarmac.
There are several Incidents reported, on 737 damaging the tarmac.

Is the distance on a B737 engine really that little comparing to
other Aircrafts (for example A320)?
Is this a design fault? Also have a look at the "Jet-blast pressure study" page 13-14.


texts: Why does Schiphol Airport have such a long taxi?

texts:
I recently flew into Schiphol and experienced a very long taxi time (about 20 minutes) from landing to pulling into the pier at the terminal. Given that the flight was only 90 minutes from closing air plane doors to opening air plane doors. I feel that over 20% of flight time is a little excessive for taxiing at the destination airport.

I landed in the early evening. Around 19:30 local time with KLM.

Looking at a map I think I landed at Polderbaan runway as we crossed a main highway. Possibly the A5.

My question is: Why does Schiphol build a runway so remote when there is clearly available land nearer to the main airport terminal? And should this runway be used by short haul flights. Should it not be kept for long haul as it is the widest and longest runway at Schiphol?


texts: Why do trijets (3 rear engines) usually have a T-tail instead of a normal tail?

texts:
I'm thinking of trijets like the Tu-154, which has three jet engines in the rear. Not something like L-1011 Tristar which has only one engine at the rear.

Tu-154:
Source: Wikipedia

L-1011 TriStar:
Source: Wikipedia

Why do these kinds of jets have T-tails? Maybe the side jets get in the way of a conventional tail, but it looks to me like you could just raise those engines a little bit and enough room would appear.

My understanding is that T-tails add complexity. The vertical part of the tail has to be strengthened (more weight) since it undergoes more forces. So a conventional tail seems preferable.


texts: If skydivers cannot jump on a flight, what should I take care of when landing?

texts:
Piloting an aircraft, if skydivers cannot jump on a flight, what should I take care of when landing?

Are there any special recommendations which should be taken into account?


texts: How do airliners facilitate in flight calls for mobile phones?

texts:
How does an airline facilitate in-flight calls for mobile phones?

I would guess that over open water in flight calls are relayed by an on board link to a communications satellite.  Such a system would likely need to track the location of the aircraft.  The records from this system could provide tracking information that is not available from other sources.


texts: How can a fighter aircraft involved in a face-off detect a missile lock from a trailing aircraft so that it can make evasive maneuvers?


texts: Winglets have been discussed fairly regularly, but not much can be found on the topic of endplates. What are endplates, how do they work, and how do they relate to winglets?


texts: Are elevator trim tabs required for an aircraft equipped with movable horizontal stabilizer?

texts:
The Bombardier C-Series aircraft has a movable horizontal stabilizer. It also has Trim Up/Down (discrete) switches in the cockpit.

Is the aircraft also equipped with trim tabs?
If so, when pilot adjusts the trim using the trim switches, which surface moves - horizontal stabilizer or trim tabs?
If an aircraft has both trim tabs and movable stabilizer, when are the trim tabs used for trimming?


texts: What exactly do "captain", "pilot", "co-pilot" and "first officer" mean?

texts:
I know the co-pilot sits beside the pilot. But it's not clear for me, who is the captain and who is the first officer?

And where they are sitting during the flight? Who is in right seat and who is in left seat, and probably who will seat behind the front seats for an aircraft with more than two flight crew?


texts: What is the difference between a non-directional signal and an omidirectional signal from a radio aid?

texts:
NDB's are non directional and VOR's are omnidirectional.

What is the difference between a signal that is non directional and a signal that is omidirectional, if any?


texts: How to measure the Aircraft cabin air quality?

texts: Is there any tool or mechanism to do quantitative analysis of aircraft cabin/cockpit air quality?


texts: Is a firm landing an indication of the pilot inexperience?

texts:
In a commercial airplane, when a landing has been a bit firm, a passenger may think it was not perfect, or maybe performed by an inexperienced pilot.

(Source)

A perfect landing is seen by passengers as one where the contact with the runway is almost imperceptible. Is that true? are there other technical or regulatory explanations?


texts: Is induced drag essentially nothing more than a specific type of form drag?

texts:
If I were standing outside on a windy day holding a flat rectangular object such as a food tray up in the wind, orthogonal to the direction of flow, the drag created would be classified, mostly, as form drag; a differential in pressure from the higher pressure upwind side of the tray and its lower pressure downwind side.

If an airplane's wing began at a 0 degree angle of attack and were slowly rotated to a 90 degree angle of attack, lift would increase until the critical angle of attack is exceeded, but the coefficient of drag would continue to increase up to 90 degrees.

I assume the drag created by the wing at 90 degrees is much like the form drag created by the tray in the wind.

Is induced drag nothing more than form drag with a different classification due to its usual nature of discussion in regards to lift?


texts: Why are liquid ring compressors not used in a jet engine?

texts:
A question has been asked here before whether sliding vane compressors could be used in place of axial compressors on jet engines since they have a high compression ratio per stage (Why were rotary vane compressors never used in jet engines?), the answer being that the sliding seal would give out at the RPMs required.

What about a liquid ring pump?

It's essentially a sliding vane compressor where the seal is provided by the mass of liquid moving along the circumference. Is it possible to maintain a mass flow of the same order as axial compressors with these? Please ignore the question of cooling of the liquid for the purpose of this discussion.


texts: Why don't airplane turbo piston engines have boost control?

texts: Why is it possible to over-boost piston aircraft engines? All turbo car engines have a wastegate that just vents pressure back to the intake, whereas in an airplane the pilot has to look at the manifold pressure gauge to protect the engine.


texts: What is the effect of thrust vectoring effect on the rate of turn?

texts:
I just got a question after reading my old Principles of Flight book. The equation for the rate of turn is $\textrm{ROT} = 1,091 \cdot \frac{\tan(\phi)}{V}$,
with $\phi$ denoting bank angle and $V$ denoting airspeed
How would that change when the airplane is equipped with thrust vectoring like the F22 or SU35? Is there an equation for that?


texts: In the early days of flight, were there any cockpit control schemes other than the modern one?

texts:
Back in the early days, what kind of control schemes were invented for aircraft, other than the modern one? (pedals to yaw, yoke to pitch and roll).

I'm only interested in control schemes that can be done from the cockpit and control relatively small surfaces. So no weight-shifting, no wing-warping.

Hypothetical examples: 2 yokes (1 for each aileron and elevator), a steering wheel?, one-axis yokes?


texts: I accidentally deviated from an ATC instruction as a student pilot. How bad was it?

texts:
Here's the scenario: I was a student pilot on inbound for landing at my home airport on my final solo cross country flight I needed before doing a checkride.

At roughly 8 miles out to the north west, I established contact with the tower and was told to "enter left base, runway 7, report 3 miles out." I interpreted the "report 3 miles out" as to give the tower a call when I was 3 miles away from the field, ie, when my GPS indicated I was 3 miles from the field.

Now, it was the most windy day I had flown solo in so far (15kt gusts) so I wanted to make sure I had ample time to line up with the runway on final and get a feeling for how the winds were blowing since the ATIS reported them as being variable in direction.

That said, what I ended up doing was making a wide base, except apparently I made it a little too wide because the GPS did not indicate I was 3 miles from the field until I was on final. At this point, I called the tower, reported I was on a 3 mile final and was given clearance to land. After landing, I still had no idea I had done anything incorrectly as the controller made no indication to me.

A few hours after I landed, my CFI sent me a text message asking me how "report a 3 mile base" meant "report a 3 mile final and fly a straight in approach." I'm not sure if he was on the frequency when it happened or if the tower controller called him after the fact and told him about it because I was told to "report 3 miles out", not "report 3 mile base."

I completely understand that I made my base leg too wide and that caused me to deviate from an ATC instruction. What I'm wondering is how bad of a screw up is this? My CFI's reaction was one of legitimate anger and it makes me want to stay on the ground for a while.


texts: Is there a penalty for changing the approach procedure after accepting one?

texts:
For example: If you request a visual approach and get approved, but you meant to request an ILS approach, are you not allowed to change it?

Is there some type of penalty for changing approaches after you've already received one?

For example in the video, "PilotsEYE.tv - A380 Landing KSFO San Francisco", the copilot misread a visual approach as ILS, and was given the ILS, but despite the captain's disapproval, they didn't make another call requesting the change.


texts: Where can I find United 757 Checklists? (CRM, Pre Start, Pre Takeoff)

texts:
Where can I find United 757 Checklists (CRM, Pre-Start, Pre-Takeoff)? I need these for a writing project that I am doing. Any help is greatly appreciated. Thanks in advance!

Thanks, Charlie :)


texts: How does the glide ratio change with velocity in a glider with air brakes deployed?

texts:
I'm interested in how the glide ratio steepens when increasing velocity, starting from the best slope (best L/D) velocity, in a high drag configuration (air brakes fully extended on a glider).

I've seen several graphs of how L/D changes with AOA for various powered aircraft (and not in a high drag configuration), but couldn't find a relevant one.

Will be happy to see a L/D vs AOA graph and/or a sample polar in clean vs dirty configuration.


texts: Are there any autoland capable aircraft without autothrottles?

texts:
While reading the question Why couldn't the CRJ100/200 be equipped with triple-string autoland? I thought the CRJ cannot have autoland because it is not equipped with autothrottles. Somehow I always thought this would be a requirement. However, after doing some research I found that this is not the case:

(a) An automatic landing system must include automatic control of throttles to touchdown unless
it can be shown that:

Aeroplane speed can be controlled manually without an excessive workload in conditions
for which the system is to be certificated;
With manual control of throttles the touchdown performance limits of CS-AWO 131(c)
are achieved; and
The touchdown performance is not critically affected by reasonable errors in speed
control.

(EASA Easy Access Rules for All Weather Operations (CS-AWO) 123 Automatic throttle control)
This made me wonder: Is there any aircraft that does not have autothrottles or autothrust, which is certified for autoland?
Note that by autoland, I mean a proper Cat II/III ILS autoland, not something like the Garmin Autoland for GA aircraft.


texts: Why do gate agents wait to ask for volunteers minutes before departure?

texts: E.g., taking the last flight out of the day. It checks in full, and the airline knows this several hours in advance.  Getting bumped would mean spending the night here again. Would be nice to avoid the commute to and from the airport, and the double dose of TSA. Why doesn't the airline text the pax and ask for volunteers via an online auction?


texts: What is this strut in biplane rigging, attached only to wires, not bearing any load?

texts:
A few biplanes like the Stearman have a strut parallel to the fuselage, halfway along the rigging's landing wires and flying wires, not fastened to the airframe, not bearing any obvious load.  One on each side.  What are they for?  What are they called?
I'd guess that because some of the Stearman's wires are doubled (also unusual?), the strut prevents them from banging into each other and chafing.  But that seems unlikely because their tension is 800 to 1400 pounds, according to page 24 of the Dec. 2007 issue of Vintage Airplane (p. 26 of the pdf).  Even if a maneuver temporarily halved that tension, deflecting one of those by two inches to hit its twin would take tons of force.

(image source: Wikimedia)


texts: Up until 2016, Boeing used customer codes that were part of the aircraft type (ie. Boeing 737-8SA where 'SA' is the customer code). What was the purpose of this and why were they not used on the 787 and eventually discontinued in 2016?


texts: What good reference books for aviation (ATC & AOC) systems are there?

texts:
I am looking for a good reference book or research paper that describes the services and applications offered by air traffic control and Aeronautical Operational Control in detail.

Everything I have read so far just outlines briefly what these services are intended for. I need something very thorough with all the standardizations and details that are being used in current aviation systems, particularly from a communications point of view. Any suggestions?

What are the best textbooks or reference books that aviation researchers or experts use?


texts: Do pilots get more fresh air than passengers?

texts:
There is a famous air travel myth claiming that "pilots get more fresh air than passengers".

       (source: The pure cure, p.375)

I would like experts to either dispel or confirm this myth, that pilots receive "better air" with higher oxygen levels than passengers, who have to breathe more recirculated air.

Although at first glance it might sound absurd, but when you think about it, it would actually make sense, because:

The worst thing that can happen to passengers is that they get tired. Sure, that may be unpleasant (think of the stale air in a crowded room), but does not pose a health or security risk.
Pilots, on the other hand, need to be wide awake and perform to the top of their abilities, as errors can be fatal. So any negative outside influences on pilot performance needs to be eliminated. In particular, pilot fatigue significantly increases the risk of pilot error.

However "CO2 levels directly affect pilots’ flight performance" as was tested in a study on 30 active commercial airline pilots performing maneuvers under varying carbon dioxide concentrations:

  press release
  Previous research led by Allen and colleagues found that, in office buildings, CO2 concentrations between 1000-2500 ppm – levels once thought to be benign – negatively impact the cognitive function of employees. For the new study, they wanted to determine if higher CO2 levels on the flight deck would impair a pilot’s ability to perform advanced maneuvers and manage emergency situations, such as a single-engine failure during takeoff. […] Average CO2 levels on the flight deck are less than 800 ppm. However, they have been measured as high as 2000 ppm on the flight deck and even higher in the cabin during the boarding process. […] The National Research Council has suggested that current standards for ventilation rates on flight decks may be inadequate.

  background
  On the flight deck […] the average CO2 concentrations are typically <1000 ppm, but the 95th percentile concentration can be as high as 1400 ppm, depending on airplane type.

  results
  Compared to segments at a CO2 concentration of 2500 ppm, the
  odds of passing a maneuver as rated by the Examiner in the simulator
  were 1.52 times higher when pilots were exposed to
  1500 ppm and 1.69 times higher when exposed to 700 ppm.

In light of the above it would make sense to prioritize pilots over passengers when it comes to circulation of fresh air.

I will post the results of my research into this question as an answer below, but would welcome other answers presenting technical evidence and quoting citable references.

scope:
This is not the same question as Q57941.
Q57941 asks if there is airflow between cockpit and cabin (as opposed to be hermetically sealed).
Whereas this question asks if more fresh air from OUTSIDE flows into the cockpit than into the cabin. Also, it addresses a very famous airline myth, and as such it has a valuable purpose.


texts: How does the X-59 acheive quiet supersonic flight?

texts: By what mechanism or combination of mechanisms does the X-59 reduce the noise produced by a sonic boom?  What are the design choices that lead to quiet supersonic flight?  I really want to understand the issue from an aerodynamic perspective as well as a design perspective.


texts:
Are there any online, publicly available sources of aviation statistics, like:

number of manufactured aircrafts by type and year
number of registered aircrafts by type and year
number of aircraft incidents by type and year
etc.

I'm aware of Annual Reports of General Aviation Manufacturers Association, but this data is just for general aviation and it doesn't contain numbers before year 1990.


texts: Would it be more effective to increase the length or chord of a rotor blade for better performance?

texts: Would it be more effective to increase the length or chord of a helicopter rotor blade for better performance? (Say, 10%?)


texts: Are there specific regulations for airports near water bodies?

texts: Are there any regulations that requires that international airports maintain a navigation channel deep enough to have access in case of an emergency when the airport runway ends near a body of water?


texts: Why would ASOS have a caution for Low Density Altitude?

texts:
I did my initial training in a high altitude area, where it got pretty hot in the summer,  so I'm not at all surprised when I hear an ASOS announce:

  Caution: Density Altitude (a few thousand above field elev.)

But recently, I was flying in SE. Kansas when it was extremely cold outside. The ASOS announced:

  Caution: Density Altitude minus 1800 ft

I understand that cold winter air can make the air extremely dense, leading to a negative density altitude. But I don't understand the caution part of it.

As far as I'm aware, low density altitudes mean your engine generates more power, and your wings generate more lift. Everything is better with low density altitudes, right?

What is the caution for?  What should I be looking out for?


texts: Do overland long-haul flights have something similar to SELCAL?

texts:
This question will be regarding airlines, flying high altitudes.

As with short flights, you are in contact with local controllers, then get passed off to enroute and local again.

I am familiar with SELCAL, where you do not have to listen to HF Radio jumble for your 7 hour oceanic flight.

However, what if you are flying for example Dublin to Hong Kong, not crossing oceans. Will you be in contact with ATC the whole time, and the pilots on duty always having to wear headsets just in case if ATC wants to find them? Or would there be a system similar to SELCAL where they will buzz the aircraft only when they need them?

(skyvector.com)


texts: How would an Inverted Delta Wing planform behave, Straight part forward? Are there wings shaped this way?

texts:
There is info about straight edge wings, swept back wings, swept forward wings, delta wings.
Is there also info about a Delta wing with a straight leading edge and a tapered trailing edge, the point rearwards, like a manta ray?


texts: Can you push the throttle forward while using reverse thrusters?

texts: Can you push the throttle forward while using reverse thrusters (for turbofans)? Does this have any effect, such as strengthen the "reverse" air blanket? Is it ever used?


texts: Why does maneuvering speed vary with weight?

texts:
Aircraft certified by the FAA under 14 CFR Part 23 have many V speeds, one of them which manufacturers are required to determine and publish in the POH is maneuvering speed, or Va.

  In aviation, the maneuvering speed (Va) of an aircraft is an airspeed limitation selected by the designer of the aircraft. At speeds close to, and faster than, the maneuvering speed, full deflection of any flight control surface should not be attempted because of the risk of damage to the aircraft structure.

This speed varies with the weight of the aircraft. Why does this speed vary with weight? Additionally since manufacturers often only provide that value at max gross weight, how does one figure out what that Va airspeed is when not at max gross weight?


texts: Let's say Runway 16/34 used direction 16 for arrival and 34 for departure. Can the runway close 16 (arrival direction) and still working in 34 for departure?


texts: Where can PT-6 engine series starter-Generator diagrams be found?

texts: Wondering if anyone can direct me to the spec sheet, diagrams, and breakdowns of a typical Starter-Generator for a PT-6, say a PT6-66 series or similar. And also who are the major manufacturers of such units for turbo-props? Thank you.


texts: What type of license do you need to solo a glider in the UK?

texts:
What type of license do you need to solo a glider (cross-country) in the UK?

Wikipedia states that:

  There is no government-issued licence at present, but EASA regulations will require one by 2015.

This doesn't seem to have updated and I couldn't find anything on the  British Gliding Association (BGA) website.


texts:
Have there been any 'proper' field trials of Automated Air Traffic Control?

Specifically, something that has been tested on larger aircraft and has come beyond the drawing board. By automated I'm implying that all decisions on movements are made by computers and instructions would be for instance transmitted digitally to the cockpit.


texts: Why does a steeper approach cause an increased landing rollout?

texts:
A pilot of a high-performance airplane should be aware that flying a steeper-than-normal VASI glide slope angle may result in:

A) a hard landing

B) increased landing rollout

C) landing short of the runway threshold

This is an ATP question and the answer is B. Could anybody explain why the answer is B, not A?


texts: Can you identify the plane with number NC 14959 photographed in Boston in 1937?

texts:
I have a photo of a plane with the number NC 14959 taken in Boston on December 31, 1937. The hanger behind it says "Occidental Airlines".

I am trying to find out what kind of plane this is?

I am sure of four things:

the date,
the NC registration number,
that it was taken at Boston, MA
the photographer's name is Carleton Parker, a prominent Boston area train photographer who photographed extensively from the late 1920's to the early 1950's, primarily trains but an occassional aircraft.


texts: To what extent have political (race, gender, social class) attitudes been implicated as human factors in the cockpit?

texts:
This question is related to:

How does cultural difference impinge upon human factors in aviation industry safety?
How have deep-seated cultural human factors (particularly in east Asia) in the cockpit been successfully managed in the past 20 years?

Standard industry practices of cockpit management can invert or disrupt very deep cultural and political expectations of command and authority.

The question

What evidence is there, in research, incident reports or other documented sources, that has identified political attitudes around race, gender or social class as human factors in the cockpit?

For example:

With more women in airline cockpits, have new human factors emerged (for example, a male pilot displeased to be questioned by a woman)?

In regions with troubled racial histories (southern Africa, the USA) have race relations and attitudes in the cockpit been responsible for incidents?

In cultures where social class or even caste is very significant, have these been implicated as human factors in the cockpit?


texts: Why aren't any jet fuels heavier than Jet A/A-1/JP-8 in common use?

texts:
The commonly-used jet fuels fall into two main categories:

Straight kerosenes (Jet A, Jet A-1, JP-8, JP-5, plus, historically, JP-1), which are used in most situations because their high flashpoints make them safer to handle.
Gasoline-kerosene blends (Jet B, plus, historically, JP-3 and JP-4), which are used in very cold climates due to their lower freezing points, but are much more dangerous to handle due to their very low flashpoints.

However, even the straight kerosenes have flashpoints below 40C, which can easily be exceeded in hot-weather operations, potentially with lethal results.  Using a fuel with a somewhat heavier composition (and, thus, a higher flashpoint) would greatly alleviate this danger; for instance, the lighter diesels have flashpoints in the 50C-60C range, and would, thus, seem to be a safer choice than kerosene-based fuels for hot-weather operations (especially in tropical and subtropical climates where very hot weather is more common than elsewhere), where their higher freezing points would not be an issue.

So why aren't there any "heavy" jet fuels for hot-weather use?


texts: Why is dual crossfeeding prohibited on DA42?

texts:
Diamond 42 AFM says:

  The fuel crossfeed function can be tested simultaneously with both
  engines. Proper function can be tested by running the engines for
  approx. 30 seconds with CROSSFEED selected. The operation of both
  engines with both FUEL SELECTORS in CROSSFEED position, other than for
  this test, is prohibited.

I looked at the schematics and both fuels crossfeed pipes are completely independent and separate, including the fuel return lines and heat exchangers. Fuel flow looks almost identical (other than longer pipes) when both selectors are in CROSSFEED. So why is the manual prohibiting dual CROSSFEED ?

Maybe it's not clear from the resolution, but in the original you can see on the left image, that the cross fuel flow passes through all the filters, while the cross return line passes through the heat exchanger (the blue box on the lower right side)


texts: How do large drones communicate with ATC?

texts: For large drones like the Reaper, X-47, and aircraft like that, how do the "pilots" communicate with ATC when they need to?


texts: What are the major aircraft systems (LRUs) using the ARINC429 Protocol?

texts:
I want to know the different aircraft systems (LRUs) using ARINC429 protocol.
Why is it used instead of the ARINC 629 ?
How is it different from the different ARINC protocols like 629 and AFDX(664)?


texts: Are Belarusian ATC recordings available for Ryanair Flight 4978?

texts:
I am interested in locating the ATC recordings of Ryanair Flight FR4978, LGAV to EYVI, 23/5/2021, that had a forced diversion to UMMS in order to arrest a passenger.
I have looked online but couldn't find any recordings available, the closest I found was https://www.liveatc.net/, but wasn't able to find the relevant files, because I don't know the ARTCCs of the controllers they were talking to.


texts: Do GA aircraft pilots use predefined routes (via GPS or DME/VOR vectoring) or methods such as GPS-direct/ VOR-to-VOR in UC airspace?

texts:
Example:
Flying from RIC to IAD, the most popular and "efficient" route is BENTLY -> CAVLR3:

However, you could more simply depart north out of the RIC Class-D, intercept the BROOKE VOR on the edge of the DC SFRA, and then accept the inevitable vectors from Potomac Approach to IAD:

While the time en-route and distance are only trivially shorter, it still illustrates my point: choosing to fly a "non-standard" route is both quicker and potentially easier (without a GPS, hitting the intersections is a more complicated procedure than "direct to BROOKE VOR").
From my training I understand that these airways are primarily used to organize air traffic to reduce risk of collision in uncontrolled airspace as well as to improve flow and organization in controlled.
Which methods (routes/airways vs direct GPS/VOR/DME nav) are more commonly employed by IFR and (vs?) VFR pilots?
Thank you!


texts: How does MCAS communicate with other systems to know if the flaps are retracted or not?

texts:
How exactly does MCAS communicate with the flaps setting to know if the flaps have been retracted?

I just noticed on the preliminary report for ET302, the flaps were set at 5 degrees. It doesn’t say when or if the pilots retracted them completely. So I’ll assume the flaps were at 5 degrees the entire flight. So it makes me curious about these systems communicate, if I understand correctly, MCAS and everything was perfectly fine, the only faulty part was the AoA, so there shouldn’t have been a problem with the systems determining whether or not flaps were set.


texts: What are the Area Control Center (ACC) frequencies for Germany?

texts: I'm looking for the frequencies of all Area Control Centers (ACC) in Germany. What are they, or where are they published?


texts: What Paper Format do Boarding Passes use?

texts:
I'm looking at creating some Boarding Passes for my Virtual Airline called "Zelandas". After looking at websites like the SITA website, Wikipedia, and more, I cannot seem to find what format of paper is used for a Boarding Pass.

When I am talking about Format, I mean something like A4, or B5 etc.

Where would I be able to purchase this kind of paper, not in bulk?

Thanks, Will


texts: Are there any legal requirements concerning airline pilots and their watches? Do they have to be of any particular kind and are pilots required to wear one at all?


texts: What are the differences between a compressor wash on wing vs on test bed

texts: I work in an aircraft engine overhaul facility and I’m trying to understand the process of compressor washing engines on Wing compared to washing them in a test bed. What process steps are different on wing? Are there time/noise restrictions on wing? The cost of washing an engine on wing? Who completes the comp washes?


texts: If the VVI, FPM, airspeed indicator somehow failed you can use fuel flow to help you with your attitude (climbing or descending)?

texts: If the VVI/attitude indicators , FPM, airspeed indicator somehow failed same time and now you could not get cross control check, can use fuel flow counter(because of the decrease consumption rate) to help you with your attitude(climbing or descending) if your aircraft is in the clouds at the moment ?


texts: Why are in-flight entertainment systems not very evolved?

texts:
Why don't in-flight entertainment systems have the capability to connect to our own devices and play movies? Or why don't they have arena gaming?
Are there any regulations that prevent engineers from designing innovative in-flight entertainment systems?

I mean, what factors come into play - regulations, cost, weight, complexity?


texts: Is there a limit of how close a runway can be to the water?

texts:
Somtimes planes can either come up short or overrun a runway, ending up in the water.

Is there some limit for how close a runway can be to the water? Does it factor into the runway safety area that is required to be clear of obstacles (i.e., is water an obstacle)? Is there any requirement for displaced thresholds near water?

I am asking primarily about the US, but information about any other jurisdictions is welcome.


texts: Materials usually used in dorsals fins specifically in the ATR 72

texts:
I am an aerospace engineering student and I am having problems finding information about the materials usually used in the dorsal fin of an aircraft. I would also like to know the kind of stress and forces this part of the aircraft is under. The project I have to do is about replacing the material the selected part of the image is usually made of.
So my question is if anyone knows the material typically used in this part and if you may know any other alloy or material that could be used.


texts: How are range and frequency related in HF communications?

texts: How does the range of HF communications differ with frequency used? Is it less frequency more range, or more frequency less range?


texts: Does every state in the US require aircraft and pilot registration?

texts:
I'm aware of both Washington and Oregon requiring, by law, registration of aircraft and pilots who are based in the state.

Is this something every state does? Do states enforce it?


texts: What methods are used to perform head tracking in the cockpit?

texts:
In this question, I asked about a helmet with built-in HUD, and have a follow-up question:

What methods are used (or have been used) to perform head-tracking in the cockpit?

The website for that particular helmet (which I'm surprised exists like it does ... could I simply order one? doubt it ...) has the following (edit: here is additional information for that helmet):

  High-speed tracker with a full-spherical Field of Regard(FOR); choice of Hybrid-Inertial or Magnetic tracker


texts: What would be the potential effects of not having an accumulator in the hydraulic system?

texts: In an aircraft, what would be the potential effect of not having an accumulator in the hydraulic system?


texts: What is the difference between fuel control unit and fuel flow meter (transmitter)?

texts: Hello can someone explain the difference between the fcu and fuel flow transmitter and how they work together alongside the fuel pump?


texts: Is there a regulation that requires manufacturers to cover AD's for the life of the equipment?

texts:
I'm usually pretty good at finding regulations, but I can't find anything in this regard. I'm curious if manufacturers such as Cessna, Piper, or even Lycoming and Continental are required by law/regulation to cover parts and labor for any airworthiness directives (AD) for the life of the equipment.

For example my 1977 Cessna 177 Cardinal II recently got an AD that required a significant amount of labor to complete (16 hours I believe). This AD was covered entirely by Cessna at their expense. This isn't the first AD that I've had like this, but it surprises me that a nearly 45 year old aircraft is still being covered by the manufacturer.

Is there a regulation that requires this for certified equipment?


texts: For purposes of the FAA instrument written, which system becomes primary for pitch following an AHRS failure?

texts:
Sheppard Air claims to have questions exactly from the FAA test. I'm wondering what folks think of the Q&A for this one. It asks

In the event of an AHRS failure, what becomes your primary pitch instrument?

The given answers are

PFD altimeter
Standby altimeter
Standby attitude indicator

I thought (2) was correct, but they give (1).
What I find puzzling about this choice is that the AHRS is a measurement system that displays its output on the PFD. So if the AHRS has failed, the PFD will too. The section of the FAA handbook in their explanation refers to using the PFD altimeter for partial panel attitude reference, but says nothing about the context being failure of the AHRS. I'm wondering if I misunderstand what's meant by "PFD" and "AHRS", or is this just stupid FAA word games? (Or a Sheppard Air mistake?)


texts: What does "pitch plus power equals performance" really mean?

texts:
It is often said in aviation circles that "pitch plus power equals performance".
A. What is it supposed to mean?
B. Is it always true?
C. If it isn't always true, why is it a useful concept nonetheless?


texts: Is a pilot allowed to sleep during a flight?

texts:
While in a flight, a pilot wants to sleep.  Given that the aircraft has an autopilot facility, are they allowed to sleep for a while (e.g., half an hour)?

What would happen if it's not allowed, but they still did it?  Would air traffic controllers know?


texts: Is there a definition of light/medium/heavy aircraft?

texts:
I'm surprised this hasn't been asked before but I couldn't find it by searching.

For separating arriving aircraft, ICAO PANS-ATM-Doc 4444 Air Traffic Management refers to aircraft as "LIGHT", "MEDIUM" or "HEAVY" but I cannot find any definition of what makes an aircraft fall into any particulate category.

I would of expected a limit on MTOW for each category, does such a definition exist or is it more of an informal definition?

  5.8.2 · Arriving aircraft

  5.8.2.1 Except as provided for in 5.8.l.l a) and b), the following separation minima shall be applied.

  5.8.2.l.l The following minima shall be applied to aircraft landing behind a HEAVY or a MEDIUM aircraft:

  a) MEDIUM aircraft behind HEAVY aircraft- 2 minutes;

  b) LIGHT aircraft behind a HEAVY or MEDIUM aircraft- 3 minutes.


texts: What tests are done on aircraft wings for testing the effects of lightning?

texts: During the testing phase of aircraft wings, there are lot of testing like temperature, pressure, humidity, vibration and load/stress. Apart from these, does any one have idea which other tests are done on them for complete qualifications like like lightning?


texts: How do hot air balloons get started (without burning the fabric)?

texts: I have seen photos of hot air balloons aloft with fearsome looking burners shooting flames into the interior of the balloon. That may be fine for a fully inflated balloon. But what about when the balloon is in a heap on the ground? How do you get it inflated without burning the fabric?


texts: What do the terms "Landing Since New", FC, and FH mean on a Landing Gear RDAS?

texts:
Could anyone able to tell me the "Landing Since New" Meant? and what is the FC and FH in here?

Thanks


texts: Now I know the definition of transition altitude - it's the altitude where pilots change their barometric altimeter datum from regional pressure setting to 1013.2hPa. In USA the TA is 18,000ft. But I just don't understand the whole concept. Why can't they just set the datum as 1013.2hPa at ground before takeoff. Why does it have to be 18,000ft. Also isn't the atmospheric pressure at 18,000ft much lower than 1013.2hPa, so isn't it wrong to put this as the datum?


texts: What is the typical blade pitch angle of a ram air turbine?

texts: I'm building a simple 3d model of one and because reasons I won't be able to give it a variable blade pitch so I need to find a typical value. My google-fu has failed me so far on this.


texts: In F/A-18, where the servo-loop closure is accomplished?

texts: In the flight control system of F/A-18, where is the servo-loop closed? I mean which of these two scenarios happen: 1-The position of the actuator and servo-valve ram are sent to the flight control computer and the servo-loop is closed there in the software, 2-the servo-loop is closed near actuator that means the actuator has an interface that receives a command and compares it with the actual position. If the second scenario is what happens, the interface is digital or analog?


texts: What is the difference between a propeller and a turbo propeller?

texts: I have found the differences rather interesting between the Beechcraft Bonanza engine and a turboprop, I have heard there the same and they're different. But I need a straight answer.


texts: What do the callouts "approaching minimums" and "minimums " mean?

texts: When landing, what exactly do the phrases "approaching minimums" and "minimums" mean in a commercial jet aircraft,  when heard from the onboard cockpit voice.


texts: Why is the Beluga chartered out for oddball missions, but not the Dreamlifter?

texts:
Both Airbus and Boeing have special outsize-cargo freighters for transporting large pieces of airliner; Airbus has five Belugas (derived from the A300), while Boeing uses four Dreamlifters (extensively-rebuilt 747s).  The Beluga fleet is primarily used for moving pieces of Airbus aircraft around, but Airbus also charters them out for moving various other very large things from place to place, making a tidy profit on the side.  Not so with the Dreamlifters, which are used exclusively in the airliner-transport role.

Why is it that Airbus charters out spare Beluga capacity, but Boeing keeps their Dreamlifters all to themselves?


texts: How many aluminum panels on the top of a 172M wing from 1972?

texts:
I'm looking into getting a wing to do some experiments prior to modifying an actual aircraft. Thanks to awesome folks on this forum, I've been able to find the wing of a 172M from 1972 that I can pick up now.

However, I still need to know approximately how many panels are on the top of this specific wing. For example, anything like this 172S or this 172P would be perfect for me, while this PA28-140 configuration wouldn't work (too many panels). Do you know how I could find out about those panels for the 172M from 1972?

Thanks!


texts: What is the indicated device under the tail of this B-29?

texts:
Was lucky enough to have the B-29 "Doc" flying over the house this weekend.
What's the mechanism under the tail indicated by the red arrow? Tail-strike preventer?
I did some searching and found it in other pictures, but never a labeled diagram.

(Personal photograph)


texts: What is the reason behind the colors used for different flight categories?

texts:
In Skyvector, Foreflight and Aviation Weather Center the following colors are used for flight conditions:

LIFR = Magenta
IFR  = Red
MVFR = Blue
VFR = Green

In most contexts, red is used as the color for the most caution/hazard, but LIFR has lower weather conditions than IFR. Why use pink for LIFR?

Somebody may answer: because LIFR is a subcategory of IFR (or MVFR is a subcategory of VFR).  Are there any other IFR subcategories (other than LIFR) to justify branching off that category? It seems like a creating a subcategory branch should have at least two categories.


texts: When flying a circuit, the leg after downwind and before final is called base. Where does this name come from?


texts: In Malaysia, can someone become a LAME through self study rather than training school?

texts: Is it possible for someone to self study (without attending a training school) and individually sit for the exams required in order to become a B1 or B2 LAME in Malaysia?


texts:
What are the pros and cons of a thin cambered wing?

Does a thin cambered wing suffer from a flow separation bubble on the lower side, at cruising speed/low AoA?

Very roundy leading edge, can air fill hole behind this,is flow attached at lower surface behind leading edge,during crusing flight/low AoA?


texts: What are the advantages and disadvantages of tail wheels that cause modern airplanes to not use them?

texts:
Photos' source: Cessna 140 and Cessna 150.

According to Wikipedia here, the Cessna 150 is successor of Cessna 140. Both have two-seat capacity and a single engine.

Why was the Cessna 150 changed to tricycle landing gear from the "old school" tail wheel? If we consider that the two airplane models have the same weight and capacity, then what are the advantages/disadvantages of tail wheels vs. tricycle landing gear? Why are so few new tailwheel aircraft produced?

Note:
I mentioned the Cessnas here solely because I knew their story better, so I can more easily compare them. This question should not be considered specific to only Cessna's products.


texts: What is the advantage of combining the rudder and brake pedals in aircraft?

texts:
I've read about several aircraft having their rudder and brake pedals very close together. To me this seems confusing and prone to error. It looks easy to mistake the rudder / brake pedals and inadvertently press the wrong one when flying or taxiing the aircraft. Since these are fundamentally important controls, this could lead to disaster.

So what is the advantage of keeping the rudder / brake pedals in this configuration? Are there any historical reasons for this design choice?


texts: Why can't we extract more from exhaust gases in gas turbines?

texts:
It is seen that EGT are of the order of 600°C (What is a normal EGT range of a jet engine?) for aviation turbines and nearly the same for stationary turbines. Why can't high temperature exhaust gases are further harnessed like adding another stage in turbine section that extracts more energy?

In aviation turbines can't we just add another turbine stage like another low-pressure turbine mounted on another spool? For land-based gas turbines we can somewhat utilize these high temperature exhaust gases in Combined cycle but what about aviation engines?


texts: What are the advantages of single vertical stabilizer over a twin set?

texts: Why did the PB4Y patrol aircraft use a single fin while the B-24 it was derived from used twin fins?  I have read that the twin fins were thought to be superior but this was realized to be false.  Why did engineers believe the twin fins to be superior and what caused them to reconsider?


texts: Why is the flight path from Taipei to Tianjin not a straight line?

texts:
The flight path from Taipei, Taiwan, to Tianjin, China, does not go directly to Tianjin in a straight line.

Instead, it heads directly north, then banks left (west) before heading north again.

(Actual flight CCA188, source: FlightAware)

Possible route: PIANO L3 VIOLA R596 OKATO W13 PINOT B221 OKTUG W506 HGH W554 DOGVI A470 PIX A593 VYK VYK9A/16R (used by virtual crews on simulation networks, source: VATAware.)

Does anyone know why this is?


texts: What prevents a commercial jet from electronically "resetting" the way a computer sometimes does?

texts:
I've had a fear of flying for the past several years and one of the ways this irrational phobia manifests is concern over the airplane power-cycling in mid-air: engines cutting out, control equipment powering off, etc.

Occasionally a computer or smartphone will crash and reboot itself, or in a worse case, the power supply or battery will fail and the device will not turn back on.

Does this ever happen with commercial jets? I expect that they are electronically wired up in a fundamentally different way from computers, so that one system failure does not affect the rest, but I've never asked a pilot.


texts: Why are the cockpit displays swapped between the captain's and first officer's sides?

texts:
This question focuses on Airbus, like the A320, but is not restricted to those aircraft as the situation seems to be the same for other aircraft.

In front of the left seat, the navigation display is displayed at the right of the the primary flight display, and it is the inverse of the right seat.

Is there a technical reason to do so? An historical one?


texts: Would this modified tire work to prespin an aircraft tire?

texts:
In order to decrease that initial hit of the tire spinning up to ground speed on the runway, could adding a blades or shape into the tire rim of a commercial plane save on tires by prespinning the tire like a pin-wheel prior to landing?

Related: Why are aircraft tires not pre-spun prior to landing to preserve them?