texts: How many serious airline accidents have been caused by design faults alone?

texts:
That is, in the chain of events that led to death or injuries in an airline accident, how often has a design fault been solely responsible?

By a design fault I mean a problem such that even if the equipment:

were maintained and operated to the highest possible standards
flown in ideal conditions
by pilots who committed no errors
unaffected by manufacturing defects
endured no bad luck

eventually it would still inevitably eventually kill or injure its passengers.

I can think of only two examples: the early Comet's square windows, and the Boeing 737 rudder power control problem.

All the others I can think of include errors of piloting, manufacture, maintenance or just plain bad luck in the chain of causes.

Are there others?


texts: Have any airliners successfully landed on a runway after striking a tree?

texts:
There are many examples of aircraft striking trees during a crash sequence, usually with high fatality rates.
Have any airliners struck* one or more trees and proceeded to successfully land on a runway at an airport without any fatalities?
*Struck in this case meaning physical contact during flight which caused significant damage beyond scratches, such as denting, broken lights, partial loss of lift and/or control.
If I understand the terminology correctly, these incidents would be "Controlled Flight into Terrain (CFIT)" with subsequent airport landing without loss of life.
The closest I'm aware of is Scandinavian Airlines Flight 751 which lost thrust from both its engines and glided mostly into a clearing, striking trees as it went down.
Disclaimer: Long-time lurker, not a pilot, just enjoy the community and learning about aviation safety.


texts: Can ATC decide whether or not to provide tower enroute services?

texts:
Recently, when I requested tower enroute service from a Southern California airport with published TEC routes, I was told by the controller that, out of courtesy for him, I needed to prefile.

If I wanted to push the issue, would the regulations have been on his side, or mine? What good is TEC if it has to be prefiled?


texts: For a coded departure procedure (SID), Fly-At-Altitude or At-Waypoint instruction has priority in case of conflict?

texts:
I am examining various RNAV departure procedures and especially those whose purpose is to overlay the existing conventional ones. I noticed that some of them begin with a "Flight at Altitude" instruction, immediately followed by either a DF or CF leg which end at a Waypoint very close to the associated airport. As a consequence, an aircraft whose initial climb gradient is small enough will reach the specific altitude well after it has passed the aforementioned waypoint and as a result, if the CF/DF leg must be followed, it must fly backwards in order to comply.

Take, for example, ANEKI9F overlay departure procedure of Frankfurt Airport. The respective conventional procedure is charted as follows:

Below I provide its equivalent description, as it is included in Eurocontrol's AIP library for German procedures:

  Eurocontrol Charts AD 2 EDDF 5-7-34.
  ANEKI NINE FOXTROT:

  On RWY track to 4.5 DME FFM/1.5 DME FRD or 800, whichever is later; LT (MAX IAS 210 KT until established on R356 RID), on R356 RID to RID (); on R183 RID to ANEKI ().

  GPS/FMS RNAV: [A800+] - DF134 (25C)[L] / DF135 (25L)[L] - DF141 (25C) / DF142 (25L) - DF143[L] - DF137[K 210-; R] - RID[R] - ANEKI.

The problem is that fixes DF134 and DF135 are near runway's end. As a result, if the aircraft climbs even with 500ft/NM, it will still fly over those fixes. Or in other words, the aircraft will reach those fixes well before it climbs at 800ft.

My question is, which of those two instructions has priority? If the aircraft reaches DF134/DF135, will the "Fly at Altitude 800ft" order be negated and the aircraft will fly at the next waypoint (DF142/DF143) or should it ignore the initial waypoints (DF134/DF135) and keep climbing until it reaches at 800ft altitude and then fly at the next waypoints (DF142/DF143)?

If someone could point me in the right direction I would highly appreciate it.

EDIT: As J. Houggard aptly stated, an assigned adverse minimum climb gradient should exist for preventing this conflict from taking place. However, no such climb gradient is assigned, according to the following table (source: Eurocontrol AIP Library).

Even if the table implies that the assigned climb gradient of CINDY1F procedure also applies to ANEKI9F (315ft/NM), it is still not enough.


texts: How does wind affect the airspeed that I should fly for maximum range in an airplane?

texts:
I have heard that wind affects the actual airspeed that I should fly for maximum range in an aircraft.

I understand that wind will not affect the airspeed that I should fly if I am looking for maximum endurance, but what about maximum range?

How (and how much) should airspeed be adjusted for wind in order to get maximum range?


texts: Why does the Piper Cherokee (PA-28-140) engine have such low horsepower despite the very large displacement?

texts:
I'm sure this question could apply to many other plane engines, but specifically I'm looking at the Piper Cherokee PA-28-140.

Surprisingly, it appears that the engine used, the Lycoming O-320, has ~320 cubic inches of displacement but only puts out 150hp.

When comparing the horsepower per cubic inch of displacement (CID), the ratio is quite low. We have the technology (and already used it in vehicles in the 50's, 60's etc.) to achieve a better efficiency than that.

Why is this engine (and perhaps other models) so inefficient?


texts:
I just read on opensky-network (scroll down to the section "facts") that ADS-B transmits roughly as many velocity as position messages.

Since the velocity of an aircraft can be computed from two successive position  broadcasts, why is the velocity transmitted directly?


texts: Do I need special permission to land at a Landing Rights Airport?

texts:
According to the Chart Supplement, Orlando International airport (KMCO) is an LRA (landing rights airport).

What permission is needed to fly an aircraft to an airport classified as LRA? Can I just file a VFR flight plan, take off under VFR from somewhere in Florida, enter the class B with a clearance, and land there?


texts:
I am learning to fly an Ikarus-C42. The instructor I have recommends to all students that they land without flaps, because it is less to think about and because it gives you more airspeed, thus less chance of stalling or losing control on approach.

Now, I'm not one to second guess someone much more experienced than me, but I do have to ask - is this truly best practice?

I have conducted some reading on the subject and it seems that not using flaps and the consequent high speed landings performed by many students is one of the main reasons for the high incident rate that involve overshooting runways (not to mention the excessive wear on the brakes). Additionally, it doesn't seem to prep you well for the 'real world'. I can't imagine telling your F.O on a 737 'Don't worry about flaps today, it's too much to think about' :D


texts: What could cause an inadvertent squawking of 7700?

texts:
I get alerts whenever a plane squawks 7700, using a popular flight tracker application. It happens quite frequently that the aircraft, reported to squawk 7700, in actuality squawks 7550 or some other benign number.

What would cause this? Are the instruments such that it starts on 0000, and allows setting each digit with a dial you can turn both left and right?


texts: What does "traffic in position..." phrase mean?

texts: Recently heard the phrase "traffic in position..." issued by controller to one of the pilots, just wondering, what could it mean?


texts:
During high speed flight, any aileron deflection may cause the wing to twist about its torsional axis (aileron reversal).
Is it dangerous?
In what kind of conditions this occurs, what have I do as a pilot to deal with it or prevent it?
What speed should be for aileron reversal in transport type of aircraft(average)


texts: What does 00 mean on a sectional below the airport runway information?

texts: What does 00-50 mean on the sectional chart under PHNL (see picture)?


texts: Why two passenger airplanes travel side by side?

texts:
Recently (2018-08-19 17:40 UTC) two planes flew above my city (Poznań, Poland). They were heading in the same direction, kept really close distance (side by side) - both flights to Riga:

https://www.flightradar24.com/data/flights/bt634
https://www.flightradar24.com/data/flights/bt684

Is this common? Why would they do that - are there any benefits of it?


texts: What are the differences between radar flight following and traffic advisories?

texts:
In typical usage, the terms seem to be used interchangeably. However, aircraft must be transponder- or encoder-equipped for traffic advisories to be possible, for example.

What information does each provide to pilots that the other does not?


texts: How did the B707 and DC-8 fight stress at the windows?

texts:
As it is evident from this  question, 4 (or 3) de Havilland Comets crashed because of stress building around the rectangular windows.
How did DC-8 and B707 fight this problem, especially as it is quite clear that both of them had rectangular windows as well?


texts:
I was reading an article on deep vein thrombosis in air travel. It seems that the problem is more prevalent than one would think. A great deal of effort goes into preventing planes from crashing but people are many times more likely to die from pulmonary embolism than a plane crash.

I'm wondering what steps have been taken to mitigate the health risks for pilots who spend many more hours sitting in a cramped seat at 8,000 ft of cabin altitude than most passengers. The most common advice for travelers is to do exercises to keep blood flowing and get up and move around occasionally. Is this practical for pilots? It doesn't seem like there is enough leg room to do exercises, not to mention that there are rudder pedals that could cause problems if you push them at the wrong time. If one of the pilots gets up the other pilot is often required to wear his oxygen mask until the first pilot returns. This would tend to make the pilots keep their cockpit excursions to an absolute minimum.

Do most pilots wear pressure stockings? That is another way to help prevent DVT. Is this a priority among the airlines and pilots themselves?


texts: How can I tell how far I am from a cloud?

texts:
So the other day as I was flying, I started to wonder:

All pilots should be familiar with basic VFR cloud clearance requirements in 14 CFR 91.155 (and if not, then go study now!).  When flying piston airplanes, we probably spend most of our time in the Class E below 10,000 ft. arena:

This is great and all, but how can we actually determine how far away we are (especially vertically)?

I thought about using a sextant and some "simple math":

Unfortunately, I need to know my actual distance TO the cloud as well as my angle...  A quick Google search found one of these, but I'm not so sure how it will work with a cloud:

In all seriousness though, how can we stay legal and safe when operating VFR in the vicinity of clouds?


texts: In what order were the runways built at Paris Charles de Gaulle?

texts:
At its commission time (in 1974), Roissy-CDG airport did not have all its runways in service. As an example, I found an article (fr) saying the fourth (and last) runway was built in 2000. But this article does not precise which runway it was.

I'm curious about how the extension of this airport was handled. Wikipedia gives an overview of terminal  extension history but not of runway.

I imagine the first runway to be commissioned is the 09L/27L as it is the nearest to the first terminal, but then, what happened? Was the 09R/27R commissioned before the southernmost runways? Did they built a runway on the south before building the smaller outer runways? In short, in what order did they build the runways?

Bonus question: Did they already have changed the runway names?


texts: Why does MAP show ambient pressure when engine is shut off?

texts: Manifold pressure is the absolute pressure at the intake manifold and increases as throttle is increased and vice versa. However, when the engines are shutoff, the manifold reads ambient pressure. My question is, why does it read ambient pressure when engines are shut off when the throttles at closed?


texts: What happens if the crew do not set a FLT ALT in the cabin pressurization panel and leave it at zero but AUTO is still selected?

texts:
On the 737NG, will the cabin maintain a lower altitude than the plane or will cabin altitude equal aircraft altitude?
Will there be ANY cabin pressurization or none at all?
When will the HORN sound?
I know this is extremely unlikely to happen but am posing the hypothetical question in order to better understand how the system works.


texts: Why does the ATIS say "read back all instructions"?

texts: Whenever I'm at a class D, I'm always confused as to why the ATIS says "read back all runway assignments and hold short instructions." Isn't that just a given? It seems redundant and it takes up valuable time in the ATIS broadcast. If I tune in half way through the reading, I don't want to have to sit there for 5 minutes just to hear the whole thing.


texts: Can radars detect all planes, including military ones?

texts: This is with reference to a News Article that I read today. I find it scary that radars would not be able to detect an aircraft. Is it really possible? If yes, how can ATCs manage this situation?


texts: Why are there different number of propeller blades on the inboard and outboard engines?

texts:
The Junkers G 38 has four propeller blades on the inboard but only two on the outboard engines.

What's the reason for this special arrangement and is there any benefit?


texts: Do black wings have better aerodynamics?

texts:
This news article links to a 2019 academic study:
Thermal impacts of wing coloration on surface temperature during bird flight.
Most of birds have dark upper wing feathers. Dark colors keep a sunlit surface hotter compared to white colors.
Do black color or hotter surfaces improve the aerodynamics of wings?
A key consideration might be airspeed: fast air over a plane wing doesn't allow time to heat up the boundary layer so much. Birds and sailing boats operate at much slower airspeed so maybe those get some benefits?


texts: How can hang gliders and paraglider pilots prevent stall?

texts:
Aircraft and gliders usually have instruments to measure air speed and angle of attack, which should be monitored to prevent stalling the aircraft.

However, it seems that most paragliders and hang-gliders lack such kind of tools.

How do the pilots avoid stalling without these kinds of instruments?


texts: Where to find the aircraft maintenance manual for the Falcon 2000?

texts: How can I find a Falcon 2000 aircraft maintenance  manual (AMM)?


texts: Can I shoot any approach at an uncontrolled airport in VMC without any clearance?

texts: I am in IFR Flight plan to an uncontrolled airport. I find out that the weather is well above VFR limit, and hence canceled IFR flight plan. But I want to shoot an approach (with safety pilot) for my currency. In this case, can I still shoot any approach to the uncontrolled airport in VMC without any clearance?


texts: Why is there a minimum altitude for at least some high-speed jet engine restarts?

texts:
While reading this other question about envelope constraints for jet-engine restarts, I noticed something odd in the graph provided (of the relight envelope for the Honeywell HTF7000 medium-bypass turbofan):

(Image obtained from a post by wbeard52, original source unknown but presumed to be either wbeard52 or public-domain)

Notice how, although the airstart envelope extends right down to -1kft pressure altitude at speeds not exceeding 250KIAS, it suddenly jumps up to 5kft at speeds of 250-300KIAS, and then up to 8kft at even greater speeds.  At first blush, I thought that this had to do with the FAA prohibition on exceeding 250KIAS below 10kft, but, on closer examination, it's clear that this can't be the case, since, if that were the culprit, one would expect the lower boundary of the envelope to jump straight up to 10kft at 250KIAS.

The jump in the minimum relight altitude coincides with the minimum speed for a windmill start, indicating that there might be something about the process of windmill-starting an engine that would preclude a low-altitude relight - but, in that case, why doesn't the starter-only-relight envelope extend to higher speeds under the floor of the windmilling envelope?  Is this problem unique to the HTF7000, or do other jets have it too?  What causes it, anyway?


texts: How is the center of mass controlled in planes with multiple tail engines?

texts:
My understanding is that, for flight stability, the center of mass must be ahead of the aerodynamic center.

There have been some rather big jets with 2 or 3 jet engines in the tail. Tu-154 and Boeing 727 have 3 in the tail. The DC-9 has 2, and there seem to be countless small private jets with twin engines in/near the tail, like the Learjet 45.

Another example is the Concorde and Tu-144 which had a whopping 4 engines very near the tail. If I'm not mistaken those were some extra-heavy engines too since they had to be supersonic.

So if we're putting the heavy engines in the tail, what is done to compensate? Do they just use ballast in the nose? How is the center of mass kept under control?

A few more details: Engines at the tail requires stronger (heavier) empennage, which also adds more weight in a direction we do not want our CG moving. Wings still hold the fuel, so moving the large wing/fuel mass backwards just to move the aerodynamic center backwards doesn't seem like enough.

I noticed that those tailed trijets and large tailed twinjets seem rather old. There don't seem to be any new designs of large commercial aircraft with tail jets. This makes me suspicious that the configuration is inefficient. However, small private jets seem to always be tailed twinjets, whether new or old designs.


texts: Is there such a concept as 'Max Overhauls' for aircraft components?

texts:
I have never seen any overhaul-able item with a documented limit on the number of times it can be overhauled.  In all cases it was subject to analysis and predicated on it passing certain tests.  Has anyone else heard of such a limit?

If so, what examples of aircraft components with such limits and what kind of aircraft can it be found on?


texts: Which airport is the busiest general aviation airport in the world?

texts: Which airport in the world has the highest amount of flight training and general aviation traffic? I am wondering for year-long traffic totals rather than temporary spikes in traffic due to airshows or similar events.


texts: Why don't big commercial planes have full aircraft parachutes?

texts:
On smaller aircraft, like some Cirruses for example, they have parachutes attached to the body of the aircraft that can help the plane get to the ground safely in an emergency.

I'm wondering why commercial aircraft (like, say, a Boeing 737 or Airbus A320) don't do this?  I figure it might have to do with the speed a jet moves at, or maybe the altitude, but I was hoping to get a more complete answer by posting the question here...


texts: Does anybody know that why C172S POH doesn't have normal & soft field landing distance chart?

texts:
Thank you for reading my writing.

I found out that C172S, C172P model POH doesn't have normal landing distance & soft field landing distance chart or table. It has only short field landing distance.

Does anybody know the reason?

Thanks.


texts: Which one needs longer runway of an airplane between take off and landing for a constant weight?

texts: Consider we have an airplane that the weight will be constant when take off and landing (in fact will be no such common airplane right now as the fuel will be less due to engine consumption. But in an electric airplane, that will be possible, I guess). What I am asking is, which one is required longer runnway from an airplane starts taking off in the edge of the runway until it just leaving the runway (ground), compared to when that airplane is landing, from it start touching the runway until it can stop safely in the runway. How do we calculate the required runway for landing?


texts: Why does a dual-axis autopilot not allow operation in single-axis?

texts:
Image source: KFC 225 Pilot's Guide (PDF)

In a dual-axis AP, when no lateral mode is selected, a wing leveler (ROL) mode is activated and can't be disengaged unless another lateral mode is selected. Similarly for pitch attitude hold (PIT). (Those two modes are shown above.)

But why, for example, can't the AP hold only the altitude, and the pilot steers laterally. As far as I know any AP with more than one axis doesn't allow single-axis operation. Control wheel steering (CWS / attitude hold) is not what I mean.

Why's that? Regulation? Design limitation?

One benefit of allowing single-axis – I think – is for climbs and descents when there is no speed hold mode. The pilot lets the plane steer left and right, and they control the climb/descent by manipulating the power/trim. Instead of guessing the proper vertical speed – which keeps changing if it's a long climb/descent, unlike trimming for airspeed.


texts: What is the weight limit for a pilot to eject from an F-100?

texts: What is the maximum weight for a pilot to use the ejection seat in an F-100 fighter?


texts: Is it practical to intentionally stall an aircraft to execute a fast, controlled descent?

texts:
An MD-11 had an onboard fire, but had to request more flying distance at least partly to execute a safe descent (and to dump fuel). It ended in tragedy.
In another accident, an A330 descended 30,000 feet in three minutes, in control (or at least in a recoverable state) during a stall.
Right now, airplanes in general, and particularly large jets, seem to be limited to 8000 fpm. So, I am wondering, can an intentional stall really accelerate this descent in a safe manner? The very high drag would keep the airplane from overspeeding, and there's no need to certify things like thrust reversers for deployment during flight. Heck - it could even be used to speed up the approach phase of a landing, saving time and airspace.


texts: What kind of work you can get with a private pilot licence?

texts: I´m planning to be a pilot, i just want to know if you can work only with the private licence and where.


texts: When is pre-heating a piston engine important, and how does one pre-heat correctly?

texts:
As temperatures here in New York plunge toward (and below) freezing it's time for those of us without nice heated hangars to start thinking about pre-heating our aircraft before we turn the key.

Lycoming SI 1505 tells me that "The use of pre-heat will facilitate starting during cold weather, and is required when the engine has been allowed to drop to temperatures below +10°F/-12°C (+20°F/-6°C for –76 series engine models)", but the general recommendations I've been given are to preheat if it's been below freezing in the last 4 hours.

At what temperature does it start to become beneficial to preheat a piston aircraft engine prior to starting, and how does one ensure that the engine is thoroughly and evenly heated?
I'm pre-heating on the ramp, using a forced-hot-air heater.


texts: Why are jet engine nacelles, used on the same plane, so different?

texts:
One thing that is plainly obvious about the design and configuration of jet airliners is how little they tend to differ.

It's surprising then that even on the same airliner, you will see two quite different-looking engines.

I've seen A330s with "fully-enclosed" engines, and "open" engines:

(Trent 700 with exhaust mixer, image from Wikipedia).

(PW4000 with unmixed exhaust, image from Wikipedia).

The fact that both designs are used suggests that one isn't simply better than the other, but the difference seems fairly significant.

Why would an engine designer or a customer opt for one design over the other, and why do they arrive at such apparently different solutions for the same use-case?

I assume, perhaps incorrectly, that each has its own advantages and that for whatever reasons different manufacturers and customers value different ones.


texts: Is there a way to code Minimum Enroute Altitude using ARINC 424 file format?

texts:
I am studying ARINC 424 file format, and I have noticed that there is not any reserved space for coding Minimum Enroute Altitude (MEA), as far as Instrument Flight Procedures are concerned.

I find this value to be really important for properly specifying the characteristics of a procedure. It seems strange that in ARINC 424 specification, MEA is omitted. I have also checked FAA's Coded Instrument Flight Procedures file (CIFP), which are based on ARINC 424, and MEAs are nowhere to be found.

Perhaps I am missing something? Could someone point me in the right direction?


texts: Is it legal for a pilot to let passengers steer during take off and landing?

texts:
Our company plane can be flown by single pilot without the need of a copilot. Several times while flying in the company plane our pilot allowed one of our company owner's family members take off and land the plane while a number of employees were on board. Both in take off and landing the plane got violently out of control jerking back and forth to the point that everyone on board was in danger. Our pilot took back over control of the aircraft barely averting disaster. Several of us that have been on those terrifying rides have made it a point not to fly if he is going with.

Is it legal for our pilot to let him do this with us on board? In the USA


texts: How can I get started on a winglet design for a small remote controlled aircraft?

texts:
I'm a member of a student competition team, we design light aircraft (total airplane overhead area is limited to 0.9 m²) capable of carrying higher payload. The competition also limits the takeoff distance (this year's limit was 70 m).

Coming from the last event, we decided that winglets are probably a great introduction to the project, but we have no idea how to design one.

My question is basically: with this kind of aircraft (weighs about 2.3 kg empty, carries about 13 kg, wingspan is 2.8 m), what should we look for in a winglet design?

We are mostly in doubt about what kind of airfoil should we use. Should we look for less drag? More efficiency? How can we maximize the traction vector, and should we do that in first place?

We have been reading papers on the subject, but with little luck. We also don't think it would be wise to just randomly test things until we get right, so a little bit of direction would help a lot, even if it's an article that we should work around.

Thanks in advance!


texts: Which system on the 737NG decides the use of roll spoilers?

texts: Which of the 737NG systems decide to use roll spoilers? FMC? Some other flight surface controller? Does it trigger when airspeed is low?


texts: Why do the A320's centre tank pumps stop working 5 minutes after the low level has been reached?

texts: I'm new here and I'm in training course for Airbus A320. In the training material, it's said that the centre tank pumps are controlled to stop automatically 5 mins after the low level fuel has been reached. Why do they need to wait for a certain amount of time rather than stop right away?


texts:
I am making a project related to flight paths. If we are given two points in space (lat,long) and the flight headings(angles) that the flight should attain at that points.

By using the radius of turn formula, I checked whether the flight can reach the next point or not, but how can I check whether the flight can reach both the points with the specified heading or not??

Please help me out.. Thanks in advance...

Sorry for the ambiguity in the question. In the figure attached, if I need to go through points 1, 2 and 3 so on which are few points in the flight path. And if I am given (lat,long,heading the flight should attain at that point) for each point, I need to find out whether points can be reached or not. Also please suggest me the solution if I need the same heading at all the three points (say x).

And the flight should not take more than 1 turn i.e. loops are not allowed (flight should always move towards the destination).

Now, i need to head from source to destination along points 1,2,3 with same heading(q) at these three points. For example take q as the angle between source and destination. Now i want to move towards destination i.e by not turning back and no loops. Just want know whether its feasible for flight with specific radius of turn to reach the next point or not.

Or what should the minimum vertical distance and horizontal distance between the points be in order to satisfy both the points.

But we can't determine the minimum radius exactly right?? In the figure 3, point 1 can be reached with the specified heading with distance below 2 * rmin. So the condition be like delta(x) > rmin definitely because it can't reach close neighboring points but what should be next condition to check whether it can reach with required heading or not. If it is like delta(x) > 2 * rmin then figure 3 would contradict it, right?


texts: Are there schools that would hire a non-CFI ground instructor?

texts:
Do flight schools have a strong preference for the CFIs giving BOTH ground and flight instructions? Would there be any interest on the part of some schools to have a pilot, but not a CFI do the ground teaching, while their CIFs would be entirely dedicated to the flight instruction?

I am a newly minted PPL and I would love to associate myself with some flight school and teach the ground as a Certified Ground Instructor. First, it would be really fun to teach this stuff, but also I hope that I could get some financial break on getting my instrument rating (i.e. the highest level of certification I’m interested in). I’d be also interested in staying with a school longer on a more permanent basis (unlike airline-bound CFIs)


texts: On an A320, will the aircraft compensate for constant pilot rudder input?

texts:
As I understand from answers to the question What does rudder input control in normal law in an A320?:

the rudder deflection is the result of the sum of pedals input and plane's FBW command
in normal law, the FBW tries to fly with zero slip angle

This seems reasonable so that any asymmetry is automatically compensate.
But what happen if this asymmetry is due to constant non neutral pedals'input?


texts: Is freezing of windows normal in airlines?

texts:
Recently I was flying on an Airbus A320. While cruising around 37,000 feet, I noticed half of the glass on the window had frozen. But it was a thin layer of ice.

Was it anything to be concerned about? Should I have brought it to the notice of the airline crew?

Edit: Ice formed on the inside of window with a small hole in it. I guess it was the middle layer of glass.


texts:
How to choose an angle of incidence?

Looking at typical airfoil polars, it seems most classic NACA GA wing airfoils like the NACA2415, have similar properties:

A max Cl/Cd at about 5-7deg
Lowest drag on the drag polar between -5 and +5 deg, then drag increases substantially outside of this range.
0 Cm at about 10-15 deg.

Interestingly, these ranges don't really overlap.

Also, I understand for maximum efficiency, we should design a plane
to cruise at 0 moment.

So ...do we choose the angle of incidence with the lowest drag, or the highest Cl/Cd, , or 0 Cm and then adjust airplane geometry for a CMplane of 0 at cruise?

Based on the above data, my intuition says to:

determine the cl needed for Vcruise, determine the AOA needed to generate that lift on the lift curve, and check that that angle of incidence is about 2deg, near the highest Cl/Cd vs Alpha at 5-7 deg, which still gives me a bit of leeway before the drag really increases past +5 deg, , and then adjust airplane geometry to get a CMplane of 0 at my chosen Vc.

Is this correct?


texts: How do I modify the aircraft weight and balance after a battery replacement?

texts:
I am looking to replace my Gill battery with a Concord.  The regulations appear to allow me to do this as an owner.

However, the Concord battery weighs 2 lbs more.

I cant find it in the regs if I can legally modify the weight and balance for the airplane myself, or do I need an A&P to sign it off, possibly as a minor alteration?


texts:
There are many wingtip design, all made to reduce vortex related drag, and neither boeing nor airbus seems to prefer one over another. They move from one design to another at each new aircraft, always claiming the new choice is more efficient than the previous one. In detailed, all generation mixed, it looks like (non exhaustive list):

winglet: B737NG, A330, B747-400, A320NEO, A350

wingtip fence: A320, A380, B737MAX

raked wingtip: B787

EDIT: The other elements of aircraft design are almost the same for all new aircraft (low wing, engines under the wing, classical landing gear, APU in the tail, ...), so I assume it has reached a great level of maturity, nothing has to be improved and introduced on a new aircraft generation. This is obviously not the case for wingtip.


texts: What, if any, equipment on a commercial airliner is (allowed to be) inoperative most of the time?

texts: Since airliners are bound by their minimum equipment list, I was wondering, which parts/systems that are not on the minimum equipment list are often inoperative on normal commercial flights.


texts: What kind of aircraft are currently being used by Boulder County to fight wildfires?

texts:
I was wondering, what kind of aircraft are currently being used by Boulder County to fight wildfires? For example, see photo attached of a plane dropping flame retardant on a wildfire over Left-Hand Canyon in Boulder, Colorado.

I would appreciate any insight anyone can share on this. Thank you.


texts:
In this video of a more complex cockpit, belonging to the SR-71, why don't we see any windshields? Were they not required for the SR-71, or are they not captured in this video? If windshields were actually not there, then please elaborate why!

Video


texts: What is TOGA LK in Airbus 320? How to come out of TOGA LK? I see it comes in Windshear Escape Manoeuvre. How is it related to Alpha Floor.


texts:
(YouTube video)

From the video linked above, I was wondering why the engines emit so much smoke? Has something gone wrong? Poor maintenance? Isn't it dangerous?


texts: Would solar panels on the wing of an aircraft increase drag?

texts:
If a small scale UAV (wingspan <2 metres) was to be fitted with solar panels on its wings to have more power available, would the addition of these panels cause an increase in the drag coefficient, and consequently aircraft drag?

Though wind tunnel testing would be required to ascertain the exact change in drag, can one theoretically anticipate a change in drag on account of these solar panels? Furthermore, will the minimal variation in surface thickness on account of the panels result in the same?

The solar panel thickness is of the order of micrometres.


texts: When resetting the heading indicator to match the magnetic compass, do I need to use the compass deviation card?

texts:
At least every 15 minutes we set the Heading Indicator's number to match the number of the magnetic compass.

In this situation, should I consider the deviation card below the compass card or not?


texts: Why were german pilots more successful on the eastern front than the western front?

texts: I was wondering why big german aces shot down the most enemy aircraft while fighting on the eastern front. Is this because the soviet pilots were undertrained, or their flying machines were inferior? Is it something else? You see all these German aces that have shot down 100+ aircraft and most of them fought on the eastern front. Why is that?


texts: What are the pros and cons of having a side-stick versus a centered control stick in a fighter aircraft?

texts:
The Eurofighter Typhoon features a centered control stick:

While for example in the F-16 the stick is on the right side panel:

I find the latter configuration much more natural/ergonomical. Especially since the concept of HOTAS (Hands On Throttle-And-Stick) implies that the pilot has his hands on the same control element most of the time.

I've heard of one reasone for having a center stick is to allow for ambidextrous operation (operations with both hands, alternatively).
But this seems to be counter-intuitive with HOTAS, especially since the throttle controls are still on the left side only.

I find it difficult to image an ergonomical position for the pilot while holding a center-stick and a left hand throttle control.

So what are the reasons for a center stick in the Typhoon?
Any experiences of pilots having flown both types of configurations?


texts: What are the steep ramps often erected at large airports?

texts:
For example, the following white and orange striped ramp:

I've seen these at a couple large airports but I've never seen them actually used for anything.


texts: What is this substance on these pipe fittings?

texts:
In this picture from a different question I noticed some kind of colored substance across many of the fittings. It is in several different colors and looks like it might be sticky. (The pink kinda looks like chewing gum. That's even worse than the duct tape question. ;) I have circled some of them in yellow.

Is it there to mark whether the fittings have been tampered with?


texts: Why was the Graf Zeppelin's endurance when fully fuelled with both fuels less than the sum of its endurances with each fuel separately?

texts:
The LZ-127 Graf Zeppelin used a unique dual-fuel system, with both a gasoline tank and a set of gas cells filled with blau gas; the airship could be flown using either fuel or both.  The purpose of using blau gas, instead of solely gasoline, was to reduce the amount of hydrogen that had to be valved off for buoyancy-compensation purposes, by reducing the amount by which the airship's buoyancy changed as fuel burned off.1

As might be expected, the airship's endurance was highest when both the gasoline tank and the blau gas cells were fuelled to capacity; however, the figures Wikipedia gives for the LZ-127's endurance using one, the other, or both fuels are somewhat odd, to say the least:

  [...]  Some flights were made using only Blau gas carried in the dozen power gas cells which enabled the airship to cruise for up to 100 hours. Using gasoline alone it was able to cruise for 67 hours, and up to 118 hours using both.  [...]

100 + 67 = ...118?

One would expect that the airship's endurance with both fuel systems filled to capacity would be the sum of the endurance using only blau gas (100 hours) and the endurance using only gasoline (67 hours), which would total 167 hours (100 + 67), or 49 hours greater than what was apparently the actual endurance when using both fuels.

Am I missing something here?

1: Whereas gasoline is much denser than air (and its consumption thus greatly increases the airship's buoyancy), blau gas is only slightly denser than air, and, thus, its consumption alters the airship's buoyancy only slightly.


texts: What gas is used in airships to give them buoyancy?

texts:
In the 1930s Zeppelins used hydrogen as the lighter-than-air gas to fill the envelope and give the ship buoyancy.

What kind of gas is used today?
Is it still as flammable as the Hydrogen from airships of the 1930s?


texts: Is there a technical name for a several mile stretch of flight before landing?

texts:
A friend of mine lives exactly 5 miles from a small but busy airport that accepts commercial traffic (small commercial jets). Yesterday I noticed that many airplanes were flying low right over his house on the approach to the airport. They seemed to be following the same route. The main runway points in the direction of this house. Is there a technical name for the several mile 'air road' that leads to the airport runway?
Edit: Airport is Teterboro Airport (TEB).


texts: How or when can the 250 KIAS speed limit below 10,000ft be exceeded?

texts:
This arose out of a comments discussion in this question.

The only airspace I really know is the UK.  Here, a controller may issue a clearance to exceed the 250kt limit below 10,000ft for reasons other than minimum safe flying speed, e.g. to expedite a transition for spacing.

Is this common, e.g. in the US?  I know it's open ended but I'm interested in whether this is just some "local" thing.


texts: Puzzled by description of AoA malfunction theory on recent Lion Air accident

texts:
The theory for the recent Lion Air accident states that the AoA sensor malfunctioned and the airplane systems commanded nose down.
Boeing also stated this occurs when the autopilot is disabled. The implication is that the pilots had no input to disable nose down command.
Is this inference correct in the B737-Max?


texts: Does "nose dive" have a technical aviation meaning?

texts:
I've usually heard the term 'nose dive' used in a metaphorical sense -- "Wow, your stock portfolio is really in a nose dive!"

Does it have any legitimate aviation meaning?

More specifically, is it redundant?  Are there types of dives which do not involve a nose-down attitude?


texts: Why does Boeing name its aircraft B7x7 and Airbus names theirs A3x0?

texts:
Airbus and Boeing use this special naming scheme for their civilian aircraft models.

All Boeings built today are B7x7.
(In the past, also other numbers were used: the shortened version of a B707, the B727 and even older models like B367, B377 etc. )

Also, Airbus uses a common scheme: A3x0, though there a few numbers outside this scheme: A318/19/21

(Both manufacturers also build military aircrafts with different schemes, like A400M.)

So, is there a special reason for these naming schemes, or is is just that they sound good and unique?


texts: Do aircraft need special modifications for polar routes?

texts: Does an aircraft need special modification for polar routes?


texts: How do you correct a mistake on a pilot license?

texts: If a mistake is found on a pilot license, like the pilot's nationality, date of birth, or a missing type rating, how would one go about having it corrected?


texts: Does an AQP line check conducted by a part 121 carrier count as a flight review and instrument proficiency check for part 91 operations?

texts: If a pilot completes an AQP program with a part 121 airline, does completion of all training and passing the line evaluation also qualify as a flight review and instrument proficiency check for continued part 91 operations?


texts: How much should it cost to get IFR-rated? What to look for?

texts:
(Related to this question)

Many pilots have told me that an IFR rating is the most valuable thing i can do to improve my flying and margin of safety.

I know there are courses as quick as, "Get your IFR in 10 days!", but I'm unsure if that's  quality training that will stick with me.

How much should it cost for a robust, worthwhile IFR program for single engine land airplanes?
What would distinguish a worthy program from one that merely meets minimums?


texts: Why are some points shown on a STAR but not attached to the route?

texts:
I'm looking at the SERFR4 arrival into San Francisco.  There's two waypoints, STOKD and MAKRS, which are shown on the plate but aren't actually connected to the route.  Can anyone help explain why they're there, as there's no mention of either elsewhere in the route.  Thanks!

SERFR4 Arrival: https://flightaware.com/resources/airport/SFO/STAR/SERFR+FOUR+(RNAV)/pdf


texts: Is it possible for a Citation Jet not to have an APU or AIR COND?

texts:
In reviewing a number of CESCOM10 reports it has become apparent that some of the aircraft don't report APU hours (instead they report AIR COND).

Is it possible that a Citation Jet doesn't have an APU?

For those reports that do report APU hours, no AIR COND hours are reported ... is it possible that there are Citation Jets that have APUs and no AIR CONDs?


texts:
These guys say (in the discussion) that they were the only three passengers on board.

Does that mean that there was no Air Marshal on board (or one of them was?).

Aren't air marshals present on every flight?


texts: After takeoff, why do some airlines' flight attendants rise from their jump seats earlier than other airlines'?

texts:
For one airline (Air France, IIRC), I've heard

a cabin chime (presumably to apprise flight attendants ("FA") that they can get up)
then saw FAs leaving their jump seats,

far sooner after rotation than other First World airlines.

Why does the time of rising from the jump seat differ among airlines?
Isn't getting up later safer (when the aircraft's pitch is less)? I'm curious if Air France cares less about its FAs' safety.


texts: How easy is it to make a connection to the aircraft pitot-static system?

texts:
I've recently discovered the device named Levil 2 AW which gives complete navigation functionalities, including Air Data computations once it is connected to the pitot-static system.

In this regard, generally speaking, is it really so easy to connect to the aircraft pitot-static system as it appears from both product description and related videos?


texts: When crossing a mountain ridge at low height above terrain what consideration is given to turbulence?

texts:
Some background: I am not a pilot, but a researcher studying air-flow across mountain terrain using Computational Fluid Dynamics (CFD).

During my studies, I have been particularly interested by high-altitude ridges (2 to 3000m a.s.l., say 10000 ft) that are exposed to regional winds that are generally across the ridge. I have been seeing very interesting turbulence patterns above, and in the lee of the ridges (rotors).

Here is the question: what instructions are given to pilots needing to cross such a ridge at low heights above the terrain, in either direction relative to the wind? What does common sense dictate?

I am naturally thinking mostly of helicopter pilots doing mountain work, but any other aircraft are very welcome (fire-fighters, ULMs ...).


texts: Is there a conventional notation or name for the slip angle?

texts:
Angle of attack is usually designed by alpha (as in alpha_prot).

Is there such a conventional notation or name for other axes? I'm particularly interested in the slip angle.


texts: Why doesn't the centre of pressure move in the case of a symmetric aerofoil?

texts:
Why doesn't the CP (centre of pressure) move in the case of a symmetric aerofoil?
Also, why does the CP move backward in the case of a flat plate?


texts: Can a military pilot make his airplane invisible for the ATCs?

texts:
I'm writing a story about the pilot of the Austrian Air Force, who uses his Eurofighter Typhoon aircraft for unintended purposes.

I've read stories in the internets that civil pilots allegedly can make their planes invisible for the flight controllers by turning off some device (transponder?). I'm not sure if it is true, but I saw with my own eyes a pilot of a small aircraft (Cessna Skyhawk), who took off without a transponder (the antenna was broken), was told by the ATC to fix the transponder, landed, and then took off again -- now with a temporary fix that made the antenna work for a while. In other words: Pilots of small aircraft do have the option to fly with or without a transponder (at least on small Austrian airfields). I'm not sure if it's 100 % legal, but sometimes pilots do it.

But a military Eurofighter is different from a little Cessna plane.

Is it technically possible for a pilot of Eurofighter Typhoon to become invisible for the air traffic controllers by switching off the transponder?


texts: What repair can be done on this wingtip? (777)

texts:
The accident happened in August 2012 and broke the wing of the Boeing 777-200 passenger jet. While taxiing at Shanghai's Pudong airport, its wingtip hit the tail of another aircraft.

What action need to be taken towards this kind of damage?

What manual is used as reference for this repair or replacement?

(Is it Structure Repair Manual or Aircraft Maintenance Manual)


texts: What is the safe separation for landing a Cessna-172 behind a commercial airline jet?

texts: When is it safe to land a Cessna-172 after a commercial airline jet has landed?


texts: What runway length and width is needed to land a G650 and take off?

texts: How long and how wide should the runway be to take off or land a Gulfstream 650 on private ranch property?


texts: Why won't you allow someone into the cockpit while on ground?

texts:
Various regulatory authorities around the world have framed strict rules prohibiting entry of passengers into cockpit. It makes some sense to not allow anyone into the cockpit (learning from 9/11), while you are flying but when on ground, what is the harm in allowing someone to enter the cockpit? The passengers are frisked thoroughly before being allowed to board the aircraft, and if you are on the ground then there is a lot of security around. So, what are the factors behind not allowing outsiders into cockpit, while on ground?

  Visitors in cockpit, four pilots lose licence


texts: What regulation allows airlines to require flight attendants to work up to 20 hours?

texts:
What regulation can a Part 121 airline use to bypass the rest requirements for flight attendants?

Our airline has been working flight attendants for up to 20 hours using the term "irregular operations". For example: "oops, the pilot is late"; "oops, there's bad weather"; "oh, you're at your home but we still need you to make that last leg even though you will be over your hours by 3 hrs". What regulation allows this?


texts: What regulations are in place for ultralight vehicles flying over US national parks?

texts:
A flight instructor i met with recently said that flying ultralight over national parks is a crime. The law section of the powered paragliders bible has nothing on parks.

One would think that commercial vehicles wouldn't be needing to  plan around parks above a certain altitude.  But ultralight vehicles may have different regulations.

After further reading into the book,  it says "almost all state and federal parks prohibit launching aircraft and ultralights except at airports." Nothing about flying though


texts: Why don't helicopters always takeoff from a hover out of ground-effect?

texts:
I've read enough crash reports to see that helicopters discovering too late in takeoff that they lack the power to fly out of ground-effect is a serious problem.

I am wondering why the following isn't standard takeoff practice: Establish positive climb rate out of ground effect before beginning any translational flight.  Failure to climb out of ground effect would be cause for immediate ATO, and there would be this nice landing zone to abort into!

(Only in exceptional emergencies, like when a mountain takeoff gives the rotor-craft a clear glide-path into denser air, would it be reasonable to ignore this procedure.)

(I note that I am assuming that translational flight out of ground effect is always more demanding than hovering.  I vaguely remember that this is not the case, but I don't remember why, and it seems counterintuitive since translational motion always establishes a retreating blade with lower lift that then needs a higher angle-of-attack and more power to maintain lift.  So if the helicopter can't climb under full power with no translation, it would not be able to once it tries moving forward.)


texts: How does air enter and leave the cabin of an airliner?

texts:
Yesterday I flew on Airbus A320 and on the airline's board catalogue, there were written some "curiosities". On was written that the air coming from the air conditioning inside the fuselage is very dry, (3-10% humidity) because while it's warmed up from the freezing outside air, it is much more complicated to humidify it.

Firstly I never even thought that our breathable air comes from the outside.

Questions:

During flight, from where air intake is made in an aircraft?
Does this air also contain CO2 along with Oxygen dumped directly to the fuselage?


texts: What's the difference between fog, fog banks, and fog patches?

texts:
My meteorology textbook (from Pooley's Air Pilot's Manual series) has a list of abbreviations used in met reports and forecasts. They include:

FG for "fog"
BCFG for "fog patches"
PRFG for "fog banks"

What's the difference between these three?


texts: When do airline pilots arrive at airport?

texts:
How much time it takes to prepare a flight, to control the aircraft, before departures?

How much spare time takes the pilots, to reach a foreign airport? I never experienced a delay because of missing pilots because of road traffic (or road accidents), but I assume this is accounted in working time, so airlines will not push pilots to arrive too early.


texts: Why are these rivets on the 777 so visible?

texts:
Look at this 777 nose:

Source: Airliners.net

It is full of rivets.Why are they so visible on this particular aircraft? Why doesn't the radome have rivets?


texts:
The Extreme Tech website reports that

  Lockheed Martin’s Skunk Works has confirmed that it is developing the SR-72 spy plane. The successor to the SR-71 Blackbird, which was capable of Mach 3.5, the SR-72 will be a hypersonic unmanned aircraft capable of Mach 6, or just over 4,500 mph.

The article goes on to say it will be unmanned, with the full scale vehicle built & tested by 2030.

It's not that I would ever doubt Extreme Tech or the author of this story (cough, cough), but it seems odd that news of an SR-72 project isn't being far more widely reported.

Are there any other sources reporting this new project, or is Extreme Tech the only one?


texts: Why is airspeed different in climbs and descents although the AoA doesn't change?

texts:
Here are the background facts:
This excercise has the objective to familiarise the student with the slow flight characteristics.
The steps are:
1)Establish straight and level, 90% RPM, 15 units AoA, hands out trimmed. (No specific airspeed, it just happens to be appr. 110 KIAS)

Add 5% RPM (so i set it at 95%) and establish a climb with 15 units AoA for 500 ft climb. No bank, whatsoever. (Again no specific airspeed, it just happens to be appr. 100-105 KIAS)

Reduce 5% RPM so you fly straight and level at the new altitude (Same parameters as step 1)

Reduce 5 % RPM (so i set it at 85%) and establish a descent with 15 units AoA for return to the initial altitude. No bank whatsoever. (No specific aispeed during the descent, it just happens to be appr. 115-120 KIAS).

My question is simple. Why is the airspeed different? The answer might be simple. I simply can't figure it out.
Hope i clarified it as much as possible.


texts: How can dynamic and static pressure be explained?

texts:
How exactly do you explain dynamic pressure? If someone asked me what the ASI reads, I would say it reads the dynamic pressure, which is the

ram air pressure (total pressure) - static pressure = dynamic pressure

But would explaining dynamic pressure as "the pressure the pitot tube experiences through the air?

As for static pressure, how would you explain that? Would you say static pressure is the pressure the aircraft feels whether it is in motion or not?


texts: How to compare turboprop engines and with which values?

texts:
I have found this website that lists a lot of turboprop engines. I would like to compare them with as few values as possible. As an example, there are tons of different values that describe a jet engine, but the most important/significant values are thrust and bypass ratio. Out of the many different values for a turboprop engine, which would be the few most important/significant to include?
My goal with the data is to approximate (very roughly) comparative fuel usage.

EDIT: To clarify the question, what are the most important engine values/specifications that can be used to estimate the general fuel economy of the turboprop engine?


texts: How much force can the Dukane DK 100 ULB (Underwater Locator Beacon) widthstand?

texts:
How much shock (force) can this beacon withstand on impact?

Is there an FAA certification telling us anything about it?


texts: What are these little things on the evacuation slide?

texts:
I marked them with black circles. What are they for?

Source (modified)


texts: How can the landing gear fit in the small room in the engine bay on the Tupolev Tu-144?

texts:
I recently went to the museum in Sinsheim, Germany, where a Tupolev Tu-144 is on display. I noticed that the landing gear of this plane is actually way wider than the space it has available when retracted. How can this work? Does the gear fold before retracting?

Sadly, I wasn't able to find any video footage of the TU-144 retracting its gear. Please take a look at the picture I took to understand what I mean:


texts: Does the "Climbing right turn" instruction of this SID violate the "Climb to 400 feet above DER before turning" requirement?

texts:
I was examining the LaGuardia Five SID, and I noticed that for runway 13 (Coney Climb) it gives the instruction, immediately after takeoff, "Climbing right turn heading 180 degrees to intercept CRI R-043" (textual description of this SID can be found here).

However, as far as I have understood, performing a turn before covering a 400 feet vertical distance above the Departure End of Runway point is not allowed (in other words, turning before covering the Initial Climb Area). Is it implied that the pilot should not perform this turn before meeting the particular requirement?


texts: Can stainless steel replace titanium for Mach 3+ speeds?

texts:
In the documentary Wings of Russia: MiG-25 and MiG-31, they mentioned both aircraft had to use special stainless steel alloys and arc welding to withstand the Mach 2.83 - 3.2 speeds.

I couldn't help but recall the space pen vs. pencil myth. Could the SR-71 (Mach 3.3) have been built using such stainless steel alloys instead of covertly importing the titanium from Russia?

  The major supplier of the ore was the USSR. Working through Third World countries and bogus operations, they were able to get the rutile ore shipped to the United States to build the SR-71.

Since the SR-71 flew higher, I'd guess both had comparable EAS / dynamic pressures. The titanium used on the SR-71 was an alloy, figuring out which alloy to use and how to shape it caused many challenges.

So gained knowledge and cool factor aside, what other factors are there?


texts:
What are hiding under these letters?
What do they stand for?
I have read many others, but I could never understand what they mean and the pilot's career on each of them.
If possible, can anyone post a brief list and their tasks and responsibilities, please?


texts: Why is there really only one basic design for passenger airplanes?

texts:
So when I look around on the airport, I don't really see many differently shaped airplanes.

They all look pretty much the same, only subtle differences.

  Image: Aircraft Recognition

Why is this design so common? Why don't we have more extravagant designs?

Or am I not looking closely enough to appreciate the differences?

It seems like there could be so much potential for a variety of designs, offering more space and comfort for passengers for example... Or is it too risky to try something new?


texts: Do all flights need to have filed flight plans or only ones that fit certain criteria? What are the criteria?


texts: Is it possible to drive a prop directly from a jet engine without a gearbox?

texts:
I'm studying turbojets, turbofans, and turboprops. I can see that, for the latter engine configuration, a gearbox is necessary so that the propeller rotates at a lower velocity than the main compressor. Here is an image:

For the experts in the aerospace field, my question might be regarded as a bit "odd", but here I go: is there any reason why we can't use a second turbine to move the propeller with coupled shafts, instead of relying on a gearbox? The idea would be to use a low pressure turbine that moved the propeller.

I think this might be unfeasible, because the added weight of a second turbine would be higher than the weight of the gearbox itself, but I don't know if there are additional considerations to this.

But on the positive side, we would have the following (and please, correct me if I'm wrong):

Less maintenance work.
Propeller rotation shaft aligned with the main engine core (does this even represent an aerodynamic advantage?).

EDIT 1

The idea would be using two turbines. A high-pressure turbine (HP) that moved the compressor, and a low-pressure (LP) turbine that moved the turboprop. My idea was taken from the turbofan engine config.

EDIT 2

As the user mins pointed out, we would need a very slow turbine or even a gearbox. But we could design the LP turbine with few stages (say 1, 2 or 3) so that its rotational velocity would be low enough as to move the propeller without having aerodynamic losses in the tips of the prop. And as this same user pointed out, there already exists such a configuration (see here). The question then is, why isn't this configuration preferred over the "conventional" one? (i.e. the one that uses a gearbox).


texts: How does a pilot know if he has headwind, tailwind or crosswind?

texts: While in cruise, without GPS how does a pilot know the wind direction? The airspeed sensors only register forward speed. Is it a matter of reaching waypoints sooner or later? And if flying on a compass heading how do they know what their ground track is and whether or not they're being blown off course? Especially with no visual reference.


texts: How many of this aircraft were manufactured?

texts: What was the total quantity issued of this model aircraft (including any modifications).


texts: Who should design the nozzle of jet engines on aircraft?

texts:
There is a question in my mind that which company should design the nozzle of jet engine - the aircraft designer or the engine designer?

If you watch this documentary:

BBC Documentary Rolls Royce How To Build A Jumbo Jet Engine

You will see that the engine is designed without the nozzle. e.g. You see something just like the following come out from the manufacturer (Trent 700).

But in fact you will see it on aircraft just like this (Trent 700 on A330).

Which company designs this duct/nozzle/intake? The aircraft designer (in this case Airbus) or the engine designer (in this case Rolls Royce)?


texts: Why are row numbers 10 and 11 skipped on Frontier's A-319?

texts:
I'm sitting behind an exit row (the exit row is row 12), but am still not sure why rows 10-11 are missing from this plane. Note the number goes from 9 to 12.

Why are the rows numbered this way? It's the same on both sides.


texts: Why is the F-117A the only plane to use the fully faceted design?

texts:
One of the keys to the stealth capability was its faceted design. The concept is that curved surfaces have a larger radar cross-section. The idea of making all surfaces flat to reflect radar away from the receiver seems a pretty sound concept. It must have been pretty effective, since they had to treat the windows because the pilot's helmet had a major effect on cross-section.

But all of the low-observable aircraft made since, such as the B-2 Spirit and even Lockheed's own F-22 and F-35 have a significant amount of curved surface area.

Why has the fully-faceted concept not carried over into newer low-observable designs? Does it just have too much negative affect on handling characteristics?


texts: Do pilots eat the same food as passengers?

texts: I imagine it might be hard to find a time when pilots can eat, but when they do, what do they eat?


texts: What would be the ground roll and total distance to clear a 50ft obstacle given these conditions?

texts:
I'm a student pilot, the question I am trying to answer is

  What would be the ground roll and total distance to clear a 50ft obstacle given an elevation of 5,000ft, altimeter 29.52, and a temperature of 25° Celsius, winds calm.

Disclaimer: I'm going to double check with my CFI, obviously, you should too if you are unsure.

So I understand how the chart works, I'm just unclear about the "Elevation 5,000ft. Altimeter at 29.52".

My inclination is to assume that the meaning is sea level pressure is 29.52, and therefore we should adjust our input for "PRESS ALT FT" to be the altitude that reflects that average pressure, which would be 500 feet.

We round up for safety, so assume PRESS ALT=1000' and TEMP=30° Celsius, we would have a ground roll of 890' and a takeoff distance of 1645', right?

Another question: Where do I find the official documentation for converting barometric pressure into the altitude that has that average pressure?


texts: What is the theoretical maximum velocity of electric aircraft?

texts:
I'm wondering about theoretical maximum velocities of supersonic electric aircraft. I think the fastest demonstration of any type of aircraft has been close to mach 10. This was done using a rocket engine, so propulsion was not limited by air characteristics as much as an electric motor + compressor's propulsion would be (I think).

Under best conditions; Assuming an incredibly high power to weight ratio of motors, extremely aerodynamic design, strongest materials, etc.

Theoretically, does anyone know what the limiting factors in the velocity of an electric compressor propelled supersonic aircraft would be (barring energy use)? Does it depend on size, etc?

Could it reach mach 2+?

Thanks a lot in advance for any input.


texts: Why the number 6 in P6SM in a METAR/TAF?

texts:
A typical METAR or TAF reads something like this:

VRB04KT P6SM SCT025 BKN040 OVC060

P6SM means "greater than 6 statute miles visibility."  Why in particular is it 6 miles--why not P7SM or P10SM?  Particularly since sometimes METARs and TAFs list actual visibilities greater than 6 statute miles anyway:

28006KT 10SM CLR

Is 6 miles a limitation of commonly used equipment for measuring visibility, or something else?


texts:
In 747-400 documentaries it's often said that the switch from 3- to 2- crew cockpit is attributed to the digital displays that present only the relevant information, combined with the FMS.

Little to none about the control systems is ever discussed. Take the MD-11 for example, its avionics manage the systems even in an emergency, e.g., automatically managing the fuel cross-feed valves after an engine failure.

When compared to the 727, what changed in 4 years that made the 737 not require the flight engineer position?


texts: What causes noise when a plane is on the ground?

texts:
What's the loud continuous noise the plane is making when it's on the ground and the (jet) engines are visibly not running (spinning, at least) ?

I was boarding and I thought it was perhaps a compressor for the cabin air but when I entered the cabin it wasn't cool inside.


texts: What does two 'high-low' chimes in the cabin of a 737-800 mean?

texts:
Recently on a trip to Orlando on Sun Country, I came across a cabin chime that I'd not heard before. It sounded like two 'high-low chimes' in a row, so basically equivalent to someone ringing a doorbell twice.

I know that one 'high-low' means that the FAs are speaking to each other through the phone in the aircraft, but I've never heard it twice in rapid succession.

Are all 737-800s equipped with these chimes? What do they mean?


texts: Why would sea level static thrust have a takeoff and a maximum continuous value?

texts:
In the type certificate data sheet for a jet engine, there is this table
static thrust is the thrust generated by the engine when the plane is at rest with respect to the Earth and the surrounding air. So why would it have different values? And is the plane still "at rest" at these values?
Also, what is the different between thrust and sea level static thrust here?

It is from http://aerodesign.stanford.edu/aircraftdesign/propulsion/tvshv.html


texts: How to calculate the heading correction with a circular flight computer?

texts:
While flying between 2 points 120 nautical miles apart, after about 40 nautical miles we discover we are 5 nautical miles off to the right of the track.

What heading correction is necessary in order to reach the destination? How do you calculate the correction using a circular flight computer?


texts: Calculation of temperature correction for altimeter

texts:
I try to calculate the correction of cold temperature for altimeter , i use for this the equation 24 of the Engineering Sciences Data Unit (ESDU) publication but it give me very high number .
if i take for example the given conditions
altitude of aircraft 1000 ft
0 ft for aerodrome altitude
t0 288 K
temperature deviation from the ISA = 259.9812
L0 = 0.001981
the result is 599777.4389 ft is too big , the expected result is 60 ft So where is mistakes ?

EDIT :
So i corrected the ISA dev according to what Ralph said but the result still incorrect i joint the step of calculation :

the expected result is 60 ft


texts: Why bother having different engine options on one aircraft?

texts:
When an airline purchases a new passenger jet, they often have a choice of engines (from different manufacturers). Why is this?

I would expect that one of the engine options is "best" and that all customers would buy that option. Thus it wouldn't be worthwhile to certify and offer the other (unwanted) options. Evidently this is not the case, so the question is why.

I can think of two possible reasons for this:

Different customers may have different requirements (e.g. shorthaul versus longhaul routes, operating in hot or cold environments) and different engine options have differing performance (e.g. better cruise efficiency versus climb efficiency or better performance in hot/cold temperatures). But I can't imagine that the requirements would be significantly different and, if they were very different, they would buy a totally different plane, not just a different engine.
Business/legal considerations: Perhaps airlines have contracts with engine manufacturers separate from aircraft manufacturers. e.g. British Airways may have a special relationship with Rolls Royce (possibly due to trade tariffs). But, again, I would imagine that airlines would always seek the most efficient engines, rather than signing such contracts.

Are either (or both) of these reasons right or is there a totally different reason?


texts:
I found this photo of a fighter jet being cleaned, how does this process work?

(usatoday.com)


texts: How much lift is created by a half-sized rotor?

texts:
I wonder if lift is directly proportional to the diameter of the rotor disc.

For example, if an engine spinning a 26 ft diameter rotor can lift 635 kg, will a 13 ft diameter rotor using the same engine lift 318 kg? The power absorbed by the rotor is the same in both cases.


texts:
I was thinking about propeller design just now and it came to mind that, theoretically, the air displaced by the propeller after every rotation might not be able to "flow back" into the area "served" by the propeller, resulting in a propeller surge, I guess you would call it.

Does this generally happen, is this accounted for in general or only in very detailed calculations or basically not at all? Does it have a name?

Edit: At high RPMs, of course.


texts: In military aviation, crews will sometimes refer to "angels" meaning MSL altitude. However, one might guess that it is a pronunciation of AGL (AnGeL), above ground level. Did it originally mean AGL and then at some point it changed meaning to MSL?


texts: The F16's maneuver envelope is better under 15000 feets but usually they will go much higher altitudes. Why?

texts: The F-16's maneuver envelope is better under 15K feet, but they  go much higher. Why do they put in that compromise position?


texts: What's a similar looking aircraft to this illustration?

texts:
There is this crazy picture of a plane or a boat or both...?

This is just a drawing, I know, but if this aircraft does not exist, is there perhaps a similar looking one in reality?


texts: What is the rule of thumb for land/taking-off on a sloped runway?

texts: Skyvector lists the gradient for KMCI as 0.3%.  What is the rule of thumb for how large a gradient needs to be before you always take off downhill and always land uphill like they do at Lukla?  Assume winds are not a factor.


texts: When was the last time the US Standard Atmosphere 1976 was updated?

texts: I imagine due to slight changes in Earth's atmosphere or more accurate instrumentation it's been updated at least once, but also because it's understood to be a less precise model we might not have even bothered. I haven't been able to find any evidence/papers so far detailing the changes, however.


texts: What was Korean Air 672 doing at the time of Malaysia Air 370's disappearance?

texts:
In the first part of this YouTube video, you can see an aircraft supposedly flying 4x faster than the surrounding aircraft, at the time the Malaysian 777 went missing.

After replaying this on Flight Radar 24, KAL672 departs Kuala Lumpa a short while before MAS370. It then does a 180, flies back towards the airport, then appears to do another 180 and rockets across the ocean:

Here are the playback links for 2014-03-07 16:55: KAL672 and MAS370.

Essentially, my question is, what is this oddity that FR24 is showing? (to ward off conspiracy theorist nuts).


texts: Do any airlines publish their policy on CRM / Do Not Pair?

texts:
A question came up recently on Skeptics.se regarding the implementation of "Do Not Pair" lists in Airline operations. I am skeptical of the answer given (irony?) which ascribes the implementation of the Do Not Pair list to the accident on board Northwest Airlink Flight 5719 - an incident which was in part caused by bad CRM.

However, the NTSB report does not suggest any sort of changes to the pairing of Captain/FO's which is what makes me skeptical that anything such as this actually exists within the industry.

Is there any documented evidence that Captains or FO's can in any way affect who they get paired up with? A single example would suffice.


texts:
I am trying to build an Aircraft, The weight of the Airplane will be around 40 Kg with engine and 8 liters of fuel and with me the total weight will be around 90 to 100 kg and I want to use a motorcycle engine in the aircraft, the aircraft will be one seater and I have a question that which type of engine is best to use,

Displacement    123 cc
Engine Type 4 Stroke, Air-Cooled, SOHC
Max Power   10.7 bhp @ 7500 rpm
Max Torque  10.40 Nm @ 6500 rpm

The engine produces a maximum peak output power of 11.00 HP (8.0 kW) @ 9000 RPM and a maximum torque of 9.80 Nm (1.0 kgf-m or 7.2 ft. lbs) @ 7000 RPM

So should I use 1070 or 1065 size wood propeller and if this size is not suitable so please recommend me the best size,

If this plane successfully flies so what would be speed of it and will it give me same mileage as the engine gives in Motorcycle? And for how long I can fly nonstop with these engines,

Mine Airplane design would be like this

Please explain me as simple as possible, and Sorry for Bad English. thanks


texts: How do Class B transitions work in the US?

texts:
I'm just wondering about VFR requests relating to class bravo airspace in the US:

Is requesting VFR flight following in a class bravo the same thing as requesting a class bravo clearance?
Does requesting a class bravo airspace transition automatically include VFR flight following (radar traffic information service)?
If I am cleared into the bravo airspace and the controller gives me a heading and altitude to fly that clips the airspace of an underlying class C / D airspace, have I satisfied the requirements to enter said airspace (class C - 2-way communication and squawking mode C, class D - 2-way communication)?
Why does ATC provide traffic advisories for VFR aircraft in class bravo airspace at all if they are on the hook for providing separation?


texts: What is the time information on the G1000 MFD map during a hold?

texts:
I just completed an ILS approach and went missed.  I followed the published missed approach and entered the hold.  When I entered the hold, on the MFD map a timer-like display was on top of the "aircraft" e.g. 00:00

The timer display did not increase after being in the hold for about 5-10 minutes.  I even started the timer from the TMR/REF softkey on the PFD to see if it would change the display on the MFD, and it still remained at 00:00.  Does anyone know what this timer display on the MFD during a hold is?


texts: How to lean with constant speed prop on multi-engine aircraft without EGT

texts:
This question is more about the indication of engine roughness. The procedure for leaning without an EGT is clear in the POH and Lycoming documentation which basically states as follows:

Best power:

lean until "engine roughness is noted."
Move mixture forward approx. 1/2 inch toward full rich.

Best Economy (75% power or less):

lean until "engine roughness is noted."
Enrich mixture until engine runs smoothly.

My question is what is engine roughness as defined by Lycoming in this situation?

I like to lean it until engine is clearly sputtering (no question its running rough), before I enrich, but most CFIs I've flown with lately seem to "detect" roughness with some magical senses, I think they are just going with their gut as opposed to empirical indications such as drop in MP or objectively detectable drop in engine performance.

My understanding of "engine roughness noted" would be a clear audible roughness of the engine being leaned, along with a slight, yet detectable drop in manifold pressure of said engine.

Engine Roughness is not a defined term in the POH or Lycoming documents I've read. So in my opinion it should be referring to a clearly objective condition that any person can easily identify.

I'm hoping someone can confirm or provide some objective guidance on how to identify "engine roughness" when leaning an engine on a twin with constant speed props.


texts: How does envelope protection work in Airbus vs. Boeing aircraft?

texts:
I keep reading this thing that "On Airbus the computer overrules the pilot, not on Boeing". Smells like urban myth or at least gross oversimplification. How does envelope protection work differently in Airbus and Boeing aircraft?

Boeing: as far as I understand it, it's possible to apply force on the column to override the autopilot and have zero limitations, i.e. you're free to (try to) fly the aircraft in whatever attitude you want.

Airbus: if all the systems are failure-free there's no way to override the autopilot, i.e. you cannot fly in any attitude you want.

Is my understanding/comparison accurate?

It would be really lovely if someone with factual knowledge on the matter elaborate more, maybe explaining the different laws and when they can be / are activated.

Related post What are the main differences piloting Boeing vs. Airbus aircraft? does not answer the question.


texts: Airbus A321 CFM56 Engine - Engine Anti-Ice Valve

texts:
For Airbus A321 - CFM56 engine, is there any maintenance task or trouble shooting procedure that require to removal Engine Anti-Ice valve and its hose? (except remove engine and remove the valve itself)
Thank you guys.


texts: How will the Boom SST not require an afterburner?

texts:
The company Boom is developing a supersonic airliner (SST).

In one of their blog-entries1 they state they would not need to use after-burners because they use modern turbo-fan engines.

Does this mean they will use a variable geometry exhaust?
Is there another (efficient) way to become supersonic with turbo-fan engine?
Which turbo-fan engine are they planning to use?

1: blog.boomsupersonic.com/why-we-dont-need-an-afterburner-a4e05943b101


texts: Can the phrases "carbon fibre reinforced polymer composites" (CFRP) and "carbon fibre-epoxy composites" be used interchangeably?

texts: Does the "polymer" in CFRP imply the use of an epoxy resin?


texts: Why do pilots have the ability to turn off the transponder in-flight?

texts:
These days, when reading news about missing Malaysia Airlines Boeing 777-200, I keep coming across a scenario where pilot might have deliberately turned off the transponder which is used for the communication of flight with ATC.

When there is a possibility that any bad thing can happen when pilot turn off transponder, why would one give the ability of turning off the transponder to a pilot when he/she usually depends on instructions from ATC or flight control. Is there anyway that ATC can turn on transponder back from ground?


texts: Is solar power used (as auxiliary power) on commercial aircraft?

texts:
Are there any commercial aircraft that use solar energy in terms of auxiliary (not as main power source, as of now) power source ?

If Yes, In what forms is the solar power used?

If No, Why isn't solar energy used in commercial aircraft as an auxiliary power source?


texts: What does "inertial" refer to in "inertial reference"?

texts: An ADIRU makes use of air data reference and inertial reference. Inertial reference calculates the heading, position, ground speed and attitude. I was wondering why is it called inertial. Is it related to the term inertia/mass?


texts: Why were there so few general-aviation aircraft in South Korea in the late 1990s?

texts:
While reading the AAIB report on the crash of KAL 8509, I came across (in section 1.17.11, “Korean aviation statistics”) this surprising information regarding the South Korean aircraft population in 1997:

  [...]  In addition there were 57 aircraft (including helicopters) operating in the commuter and non-schedule area of the market and 44 general aviation aircraft.  [...]

(Page 58 of the paper report; page 70 of the PDF file of the report; emphasis added.)

This is a mind-bogglingly tiny number of general-aviation aircraft for a country with as many people as South Korea (45.95 million in 1997), coming out to less than one general-aviation aircraft per million citizens; in contrast, in the same year, the U.S. had slightly under 200,000 general-aviation aircraft distributed among 272.9 million citizens, or approximately one general-aviation aircraft per 1,200-1,500 citizens.

Why was the South Korean population of general-aviation aircraft so small in the late 1990s?


texts: Do frequency response / Bode plots for an aircraft or helicopter come from modeling or empirical testing?

texts:
I was intrigued while reading an article by this snippet:

  Examination of the V-22’s frequency response plots (Bode plots) in
  2000 showed that the aircraft failed to meet the basic stability
  requirements mandated for rotorcraft and was indeed PIO-prone.
  Since 2000, the Navy and Bell/Boeing have stated that the frequency
  response of the aircraft has been modified to remove this tendency.
  Updated Bode plots have not been made available to date.

My question: How does one go about obtaining frequency response plots for an aircraft? Is it a modelling exercise or an  empirical one?

http://www.g2mil.com/V-22safety.htm


texts: How to calculate turbojet thrust at variable altitudes and mach numbers?


texts: Is engine sync to avoid beat frequencies also a concern for jet engines?

texts:
Is synchronization of rpm to avoid beat frequencies also a concern on jet engine aircraft like it is on propeller driven airplanes?

Context:

This question on SE-Aviation discusses prop sync for multi engine prop aircraft  to eliminate beat frequencies that can be annoying. But it says nothing about any multi-engined jet aircraft.

On the other hand, this other question on SE-Aviation refers to why it is preferable to run all engines at the same RPM (and hence differential thrust is NOT used for directional control) and I presume the answer applies to both jet and prop aircraft.

Which begs the question above:

Is synchronization of rpm to avoid beat frequencies also a concern on jet engine aircraft like it is on propeller driven airplanes?

If it is, how is this done in typical modern jet aircraft? Is there an automatic system in the FADEC etc?


texts: Have there been any incidents caused by an inability to shut down an engine?

texts:
I read many items on the avherald.com site where it says "engine shut down during flight" or words to similar effect.

I'm wondering if there are any instances where an engine could not be shut down or the pilots had trouble shutting down the engine when commanded. What sort of backup systems are in place to avoid this kind of scenario?


texts: Do fighters or bombers ever ditch their weapons?

texts:
I was just reading about the reasons why commercial aircraft will sometimes need to dump (or otherwise consume) their extra fuel. Things like decreasing landing weight, speed, reducing fire risk, etc.

It seems like the same would apply to fighter and bomber aircraft with their weapons as well.

Do these aircraft ever ditch their weapons (presumably in a disarmed state) if forced to land in an emergency? If not, why?


texts: Will leaving the ducting on the propellers attached to a DIY aircraft give it more thrust?

texts:
I'm not sure if its the right place, I have a problem with a flying thingy, and you like flying thingies, don't you?

I will be trying to add some means of propulsion to my friend's styrofoam plane (3ft wingspan, 2-3ft length). I have quite a few computer fans lying around, so I decided to add four (two on each side of the hull) 1W, 2x2 inch fans. Now you don't see a lot of propeller planes with their propellers ducted (well, maybe except for jet engines, but they are a different animal), do you? Now, I heard that ducting equals more efficiency and thrust.

So should I snip the ducting off or let it stay on? I can provide more information if you need it.


texts: Are throttleable rocket engines the less efficient the lower the power setting?

texts: Are throttleable rocket engines less efficient the lower the power setting? Logically that would lead to lower pressures in combustion chamber and so lower thermodynamic efficiency. Or is it remedied by combustion chamber design?


texts: Most but not all Russian Su-27's (and variants like the Su-30, -32, -33) have a device that looks like a headlight in front of the cockpit. What is it?


texts: Do transatlantic flight plans have alternates routes?

texts:
Does every international flight have more than one flight route in the flight plan?

For example, after the incident with MH-17, most of the flights were diverted from that route. Were the alternate routes already planned or were they chosen at that moment? If they were chosen at that moment, who planned the new routes?


texts: Difference between EASA and FAA regulations for airliners?

texts:
The design of large transport aircraft is governed by EASA's CS-25 regulation and the FAA's FAR Part 25 regulation.

It seems however that these regulations are nearly identical. It is obvious that a lot of collaboration took place between the two authorities in the creation of these standards.

Are there any major differences between these standards?


texts: Can the FAA CPL 2-hour cross country flight requirement include stops?

texts:
One of the requirements for an FAA commercial certificate is:

§61.129: (3) 20 hours of training on the areas of operation listed in §61.127(b)(1) of this part that includes at least—
...
(iii) One 2-hour cross country flight in a single engine airplane in daytime conditions that consists of a total straight-line distance of more than 100 nautical miles from the original point of departure;

Since it just says 100 nautical miles from the original point of departure, would a flight that was 268 NM and 2h 29m, but included a stop halfway count for this requirement?
Also, does the "20 hours of training" mean that the 2-hour/100 NM flight needs to be with an instructor?


texts: Do aircraft have radar or other forms of traffic sensing?

texts:
Quicky question.

Do modern commercial aircraft include radar to detect traffic in their vicinity or perhaps have some mechanism to receive transponder signals.

I know they have forward facing weather radar but the ability to detect and be warned of other traffic on a collision course would seem to be a good idea.

I'm particularly reminded of the Proteus Airlines Flight 706 incident where a mid-air collision occurred because of visual blind-spots and the ATC not knowing the other aircraft was even out there. I am also aware in this case a transponder monitor would not have helped either...

EDIT:

I suppose TCAS does do the transponder bit, but wont detect aircraft without the necessary device turned on. I'm more thinking of a short range RADAR or even LIDAR, something akin to, though longer range than, the things they are hooking up to cars these days.


texts: Vertical autorotation with passive rotor

texts:
Let's say we have a simple hollow cube(chosen for simplicity) with outside side length=10cm, thickness=5mm (or another arbitrary shape with arbitrary dimensions).

Clarification: I am NOT talking about a helicopter. It has no tail rotor, no forward speed, no controllers etc.

It has a passive rotor(no power, no engine) on top of it with 4 blades(total diameter of rotor l=30cm) (with arbitrary foil shape). We drop it from height of H.

What would be free-body diagram on this rotor-cube system?
I am imagining that there would be 3 forces. First one is downward and the other two is upward. Both velocities are descent velocities, the area S in both of them is $\frac{\pi l^2}{4}$, l being diameter of circle created by rotating blades.

Weight Force $W=mg$
Lift force $L=½ρv²SC_l$
Drag force $F_d=½ρv²SC_d$

Is this correct?  Also please post your source, whether the name of the book from or site link which you learned how to find free-body diagram of these kinds of aviation systems.

Also will all kinds of foils work in this scenario? What is the important parameter in foils that will make it start spinning and descent with constant speed?


texts: What are these two circular areas on the fuslage of Fokker 100?

texts: There are two circular areas on the fuslage of Fokker 100 which are shown in the bellow image. What are those? Why are the above these two areas written "do not paint"?


texts: How to keep an aircraft stationary with an inoperative parking brake?

texts: After High Speed Rejected T/O and an imminent evacuation, how would a pilot keep the airplane stationary with an INOPERATIVE parking brake?


texts: What do the gyroscopes used in commercial aircraft actually look like?

texts: I pretty much grew up watching Air Crash Investigation and Seconds From Disaster and every other episode had a mention of the aircraft’s gyroscopes, but I always wondered how did FAA rated industrial long use gyroscopes actually look like and where were they physically placed inside the aircraft?


texts:
Is it possible to fly an EASA registered airplane with an ICAO license?
My problem is the following: I have obtained my ICAO PPL license in Argentina with 52 flight hours but currently I live in Poland and I'm trying to convert to EASA PPL. I know I need 100 hours for the conversion process but it is not possible for me to travel to Argentina and fly those remaining 48 hours.
Am I able to fly the remaining 48 hours in Poland with my ICAO PPL?


texts: Is medical evacuation aircraft D-AIGZ "Robert Koch" protected against decompression?

texts:
In 2014, Lufthansa engineers converted a A340 into a medical evacuation aircraft specially equipped to carry contagious patients, e.g. with Ebola fever (D-AIGZ, "Robert Koch", msn 347). This aircraft was at the time the property of the German Government (as of today, 2020, it is back to Lufthansa).

Source.

The patient is in an isolation unit surrounded by an airtight tent with negative pressure:

Source.

I was wondering about how this isolation system would react in case of in-flight decompression and how the cruise altitude would be selected. Is it common to have negative pressure tents in civil medical aircraft? Is it safe? Is it regulated?

More:

Inside the flying quarantine used to transport Ebola patients, on Wired
It seems this airplane has been recently converted back to commercial transport.


texts: Can 7 AKE containers adjacent to each other be securely locked in a 777-300ER's aft cargo bin?

texts:
Is it possible to securely lock 7 AKE (LD3) containers adjacent to each other in a Boeing 777-300ER's aft cargo bin from position 31 to 41 (41 included)?

According to my experience it's impossible to securely lock 7 AKE containers adjacent to each other if a partial load stop is raised between the containers.

If a ULD lock does not get raised between containers, then it is OK to lock containers using only an end-stop at the beginning of position 31 and raising the lateral guide located at the end of position 41 (between positions 41 & 42), but I'm a bit unsure of using such a combination and find this unsafe because there are only two ULD locks that secures 7 sequential containers.

Could somebody confirm whether is it safe to do so and/or can give detailed information on B777-300 ER cargo hold loading configurations, ULD locks and ULD loading rules?


texts: How to calculate the minimum possible flight speed of an aircraft?

texts:
So for the minimum possible flight speed an aircraft can fly with for a given altitude, I just use
Lift=Weight  and solve for the velocity.
But: I need to insert a lift coefficient, which I can get from airfoil + body data table.
Lift coefficient depends on the angle of attack. Up to stall, the lift coefficient increases with angle of attack.
I have my highest lift coefficient for an angle of attack of alpha=24°
So my question: does it make sense to choose this lift coefficient?
Because: the higher my angle of attack, the less thrust of my jet engine is there to counterbalance the drag component, so I will have to give more thrust (because only the cos(alpha) component can be used of the thrust vector).
So in the end, I could use my highest angle of attack and reduce flight velocity, as long as I have enough thrust to counterbalance the drag component, is this correct?
If yes, are there any limitations as long as I do not have a stall?


texts: I have never reported reckless behavior by other pilots to the FAA, but I have thought about it several times. The only problem is that usually I will only know the tail number, not the name of the pilot. Since the owner of the aircraft may be different than the one flying it, how does one go about making sure the complaint is filed against the right person?


texts: Which photo more accurately represents Flaps 1 in a 737-800?

texts:
or  A recent update in a sim craft changed the visuals from what I'm used to, but from my research it looks to be more realistic. This post clearly reflects the more extended option being more realistic - but can anyone confirm that that is how it looks on a flaps 1 setting irl?

Thanks in advance!


texts: What is the response time of Pulse Doppler Radar?

texts:
We have the Airborne Pulse Doppler radar for weather predictions which are I think same as in the A350s and also in fighter jets so, what is the response time of these radars?

For example, if a fighter jet is travelling greater than Mach 1, how much will be the response time of the weather radar and how the response time will affect w.r.t to the speed of the plane?

Edit: Response time means how frequently the data coming from the Radar is getting updated? Like in case of Flight Radars etc, the normal response time or update time for the data varies from 40ms to 100ms.


texts:
I'm wondering what's the time for pilots.

Given the case the watch says 10:00:20 - is it basically 10:00?
And when does 10:01 start? Is it past 10:00:30 or only as the seconds move from 10:00:59 to 10:01:00?


texts: Is there a formula to converting statute miles to runway visual range? If so, what would it be? I'm seeing how 1 mile is equal to 5000 feet, but I am so confused because 1/2 of a mile is equal to 2,400 feet. I would think 1/2 would be 2500 feet. If it was half of a mile, you would take 5000 and divide that by .5 or 1/2 to get 2500. (I'm not a pilot yet)


texts: Should I fly if conditions are VFR but the flight briefer says "VFR Flight Not Recommended"?

texts:
I contacted a flight briefer this morning in the San Francisco Bay Area in California. At the time, ceilings at my airport (Palo Alto) had just hit 1000 ft, so the field was (barely) VFR. It is a very common pattern in this area for the ceiling to burn off, become broken, scattered, and then disappear.

The briefer told me there was an Airmet Sierra for IFR conditions and mountain obscuration in force, and that VFR flight was not recommended. When I talked with an instructor at the club, we talked about the specific location of the clouds and decided the whole area would soon be VFR.

Question: should I fly if conditions are clearly VFR but the flight briefer is telling me “VFR flight not recommended”? How should I think through the risk assessment here?


texts: Is there no warning if landing gear is not retracted during flight?

texts:
I know that most aircraft have a warning system which makes beeping sounds if an aircraft tries to land without the gear down. After reading this news article about an Air India flight 676 flying without retracting the landing gear, I was wondering if there is a reverse mechanism which warns the pilots if the landing gear is not retracted during flight?

If its not there, why?


texts:
If someone gets a denial on their medical or gets deferred but never follows up with the appointments, can they retake it at a later time?

For example, if someone gets denied on their medical and they want to retake the exam 10 years later will the original denial prevent them from passing?


texts: If both propellers and wings are airfoils, then why do propellers deflect air perpendicularly to the rotor, but wings not?

texts:
Here is my dilemma.  I have seen a lot of videos of airfoils in wind tunnels, and I've noticed how the airflow always moves away from the trailing edge parallel to the wing, or at a very small angle away from the wing as in this video:

I've also heard that propellers are nothing more than rotating wings (airfoils), producing lift sideways as opposed to upwards.  What confuses me is that in the case of the propeller, the airflow leaves the propeller at a much higher angle, and not straight as is with the wing.  In other words, the airflow is deflected backwards from the prop.  I just can't understand how the wing and propeller, which are two very similar shapes (maybe not that similar, but they operate by the same principle), deflect air in two radically different directions.
I have a few thoughts on why this happens, but I think it's better if someone tells my first.