# All Questions

15,793 questions
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### Is there any equation on propeller thrust that takes into account the number of blades

I had a look at both What is the equation for calculating static thrust? and Is there any equation to bind velocity, thrust and power? However, it does not mention how much would the thrust be ...
10 views

### Does propwash increase pitch stability?

Here is a polar for a piston single-engine aircraft: (This is lifted from a Russian manual for Yak-52, so $C_x$ is drag, $C_D$, and $C_y$ is lift, $C_L$). 1 is the 'normal' case without propwash. 2 ...
24 views

### Why would there be a direct segment in the middle of the airway?

An airline filed the following flight plan: [...] IRK.J96.SLN..LANCY.J134.PKE [...] The cruise altitude was around 30k feet. Waypoints in J96 are: ...
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### Question about CDI/OBS and HI [duplicate]

Could somebody please explain me the differences between using the OBS and the Heading Indicator? As much as I could understand, once you tune into the VOR, the OBS starts to show how much deflection/ ...
34 views

### What happens to a plane that goes to / from an enclave when the surrounding country closes its airspace?

When Pakistan closed its airspace, planes that had routes flying over Pakistan had to deviate around that country. What would happen to planes en route to or from Lesotho, if South Africa closed its ...
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### Determining total engine life in relation to SMOH/SFOH

When evaluating the value of an aircraft, the total hours since major (or factory) overhaul (SFOH/SMOH) is an important indicator of price since it tells us how many hours the engine has operated ...
22 views

### When a hold is distance based, do you still used a timed entry?

Let's say you have to do a parallel or tear-drop entry to enter this distance-based holding pattern. Do you still fly outbound from the fix for one minute and then make your turn inbound to re-...
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### What kind of jet plane is this? {Bede BD-5}

The cockpit can hold one person, is smaller than a compact car and as narrow as a motorcycle. What kind of plane is this and how hard would it be to fly?
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### Would this modified tire work to prespin an aircraft tire?

In order to decrease that initial hit of the tire spinning up to ground speed on the runway, could adding a blades or shape into the tire rim of a commercial plane save on tires by prespinning the ...
101 views

### Why do some helicopters have wheels instead of skids?

I have noticed on Blackhawk helicopters that they have tires but I have not seen one take off like a plane. When would a helicopter need to use a running take off or landing? When is it determined ...
870 views

### Are gliders susceptible to bird strikes?

Gliders don't travel at the high speeds that make bird strikes so devastating in airliners. However, they are also smaller, lighter and softer, and can still move pretty swiftly. Are they also ...
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### Is it possible to obtain an STC for single-pilot ops in a jet certified for two pilots?

I have been doing research on whether or not one could realistically obtain an STC for a super-midsize jet certified for two pilots and legally fly it single-pilot. For reference, my chosen aircraft ...
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### What indication will appear in case of one of A320 LGCIU is inoperative?

What indication and where it will appear in case of one of LGCIU (landing gear control and interface unit) is inoperative?
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### Plot response of a MIMO system with individual inputs in MATLAB using lsim, step or anything like that [on hold]

I need to plot response of a 2 input 2 output system with by controlling each individual input i.e For example, I want to give a reference input of 5 degree to Side slip angle and 10 degree to the ...
194 views

### Is it legal to bring your own survival gear aboard an airliner?

Is it legal to bring your own survival gear aboard an airliner? Considering the sobering article by William Langewiesche that is appearing in the July 2019 edition of "The Atlantic", one might want ...
2k views

### Why were the first airplanes “backwards”?

In the question Is the location of an aircraft spoiler really that vital? the accepted answer states "Surfaces behind the CoG act as stabilisers, keeping the nose pointing forward. An aeroplane has ...
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### Canceled regulations for an STC CCL

easy question: When creating a list of regulations (and the documents that show compliance with those regulations) that apply to our STC, if one of them has been canceled, would we continue to use ...
58 views

### What does the “test result indicator” indicate on a cockpit voice recorder?

I am really curious as to what the “green/red” strip of led indicate and the numbers below it. Having read around the web, i speculated that it could be an audio quality rating scale. Would help alot ...
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### FAR 91.215 (b)(3)(ii) — transponders— does the “or below 10,000' MSL” clause have any practical significance?

Here are some of the airspaces where FAR 91.215 requires aircraft to have transponders-- (b) ... (2) All aircraft. In all airspace within 30 nautical miles of an airport listed in appendix D,...
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### FAR 91.215— may an aircraft with no electrical system and no transponder overfly Wheeler AAF at 9500' MSL?

Here are some of the airspaces where FAR 91.215 requires aircraft to have transponders-- (b) ... (2) All aircraft. In all airspace within 30 nautical miles of an airport listed in appendix D,...
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### What is the vertical speed limit when altitude mode is engaged?

This question applies to Airbus' autopilot but may not be restricted to just this manufacturer (there must be equivalent modes on ATR, Embraer, Dassault Falcons, etc.) For the vertical plan, the ...
2k views

### Is the location of an aircraft spoiler really that vital?

I was wondering that spoilers in most of the aircraft are always placed aft (towards the tail) the CG location. Why aren't they placed ahead of the wings or near the nose of the aircraft? The same is ...
68 views

### What is the definition of “airport boundary”?

While flying in to KBTR in a helicopter, I called tower and stated “10 west, landing south ramp with information Mike”. They responded “proceed to the airport boundary”. When I was closer I got the ...
137 views

### What steps do I need to follow to use my PPL for income?

So I am currently taking my PPL because flying was always a passion. But, as I am sure all who do such can relate, it is an expensive license to hold on to. None the less we go through simply for the ...
209 views

### Can an aircraft operator hire a Commercial Pilot to fly their aircraft under part 91?

Here is the scenario. Joe owns a Cessna 172. Joe hires Tim to fly him in his 172 from A to B. Tim is a Commercial Pilot. Is this legal? So far, everyone has said yes to this question, but not one ...
388 views

### Using aluminium busbar/cables in an aircraft instead of copper [duplicate]

I have just found out Airbus uses aluminium wiring in the A380 to save weight. However, I didn't see anything about whether all the wiring is aluminium, or if copper wiring is also used. What is the ...
66 views

### Shock wave on airfoil

I was wondering the other day, during the trans sonic regime, when the velocity over the airfoil becomes supersonic,why does the shock wave standing on the airfoil moves downstream when the free ...
57 views

### Definition of Critical Part in type certification process

first time here :) I'm part of the team at Flytrex (flytrex.com) and we're working with the Aircraft Certification Office to certify one of the first UAS systems (drones) under new initiative to ...
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### Why is the alternate static pressure lower than the standard static vent pressure regardless of the venturi effect on both?

I understand that the higher relative airspeed around the body of an aircraft in comparison to the air within the cabin causes the cabin to experience a lower pressure. However, I was just thinking ...
142 views

### What needs to be considered when changing a tire during boarding/deboarding?

Passenger aircraft tires are physically inspected by the cockpit crew member or technician after each landing or before take-off, that the tire may have been cut or punctured as it may have hit ...
112 views

### One man push-back

Towberless pushback operation of a passenger aircraft is generally done with at least 2 people. The first person (walk-out assistant) communicates with the cockpit crew members and observes the ...
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### What is the average time and distance needed to reach cruising height?

I am trying to compare trains with airplanes and the distances where taking a train is more viable than an airplane. I guess this would depend on the type of plane, but the Airbus 320 seems like a ...
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### What is the difference in purpose of the 1:40 Obstacle Identification Surface and the 1:50 clearance plane for an ILS glideslope?

I have found references to the Obstacle Identification Surface (OIS), which is approximately a 152ft/NM slope from the end of the runway (1.43 degrees, 1:40 rise/run) and a 1:50 clearance plane noted ...
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### Does anyone know where I can find more information on an altimeter [on hold]

I recently acquired a B-17 altimeter I was wondering if anyone knew any sites that would help me find out where it was from or what registration for the plane or any other history with it. Here is the ...
240 views

### Why does the F-4's rear seat have a weather scope eyepiece?

In the front seat. The pilot has a flat screen radar scope that shows both the planes and the weather. But on the rear seat. The weather scope has an giant eyepiece. Perhaps glare protection? (...
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### How to calculate variation of Z force with elevator deflection (Zδe) in Nelson for pitching dynamics?

I have been trying to model the pitching dynamics of a General Aircraft (Nelson : Flight Stability and Control) but during the modelling, I find that I need to use the ...
83 views

### Why/how is a downplane parachute configuration aerodynamically stable?

One of the most dangerous situations possible in skydiving is a so-called downplane, where both the main and reserve chutes deploy, and they shift outwards to the sides of the parachutist until ...
1k views

### Why does the A-4 Skyhawk sit nose-up when on ground?

The rear of the plane is nearer to the ground, while the front part of the plane is away from the ground (see image below). Other planes are more flat. I think it was for high AoA but these planes ...
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### How does ADS-C and FMS relate to FANS?

So - I'm totally confused about FANS and its systems. From what I understand: FANS 1/A (started in 90s) has some early CPDLC for USA routes (this topic) but what about position reporting? Does it ...
58 views

### Are tiltrotor planes less safe than conventional propellor planes?

I got interested in Tiltrotor type of airplanes and was reading up about some specific models, the AgustaWestland AW609 and the Bell Boeing V-22 Osprey. Both planes have a history of quite a few ...
263 views

### What are the two blisters on F-35 upper wing surface?

For all of the F-35 models you can find pictures with and without a blister on the upper wing surface. I'm guessing that it is sensors for the missile warning system that were retrofitted later on, ...
84 views

### Virtual Winglets?

Just read this abstract by a Regeneron STS finalist. Is the idea of a virtual winglet a viable concept? Seems interesting. Link: https://abstracts.societyforscience.org/Home/PrintPdf/15282
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### How many crew does a P-8 operate with?

According to Reuters, Iran says it refrained from shooting down U.S. plane with 35 on board. The article goes onto say the aircraft was a P-8 Poseidon with 35 on board: Iran refrained from shooting ...
259 views

### Having declared a mental health condition in the past, how will this affect my plans to work as a pilot, and what should I do about it now? [on hold]

About a year and a half ago I moved into an apartment, where pets are not permitted. In order to be able to bring my pet with me, I applied online and obtained an "Emotional Support Animal" letter ...
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### Air density, temperature, pressure relation [on hold]

If the pressure increases the density increases If the temperature increases the density decreases If the temperature increases the pressure increases Then when the air is heated the pressure should ...
96 views

### Can an S-duct fit a turbofan exhaust instead of the intake?

Can an S-duct fit a turbofan exhaust instead of the intake? The idea here is to merge 2 exhausts into one at the exact center of the tail. This would be for twin-engine aircraft that have both engines ...
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### Aircraft Registration for 2015 Flight? [duplicate]

Back in 2015, I flew on 4 flights with Delta Airlines. I was too young to remember the registrations of each aircraft. Is it possible to look up the tail numbers if I have the date of the flights, ...
104 views

### What is the cabin noise hertz in typical commercial aircrafts?

In cabin, we hear noises in commercial aircrafts. Wondering if it is in general over or under 100 hz. There should be a band width. Thanks!