# All Questions

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### What is the average climb gradient of an aircraft during the takeoff and early phase of a departure procedure?

On chart plates it is written the minimum climb gradient with which an aircraft should climb for obstacle clearance or after ATC request (for traffic flow management etc.). However, since this is the ...
160 views

### Where do the compressed gasses of a charged engine goes?

Good day to you here. I'm working on a modified version of 2-stroke engine. My plan is to use a supercharger for the scavenging process, instead of the conventional Crank case scavenging technique, ...
156 views

### What is the effective difference between top and bottom mounted airbrakes?

What is the effective difference between airbrakes on the top side of jet aircraft (like on the F-15) compared to those on the lower side (like on the A-7)? From Wikipedia. From Reddit. Would pitch ...
97 views

### How is the total drag variation with velocity related to altitude?

Here in the question given I am confused how to relate the altitude with the given plot of total drag and velocity.
298 views

### Do they wait until all aircraft have landed before winding up an airline?

This BBC article suggests that any announcement about winding up Thomas Cook will wait until late at night and all its planes are on the ground (I guess they don't fly long haul distances?) before an ...
125 views

### Stability and Control of an aircraft [duplicate]

Why is the pitching moment coefficient of an airplane said to be constant about the aerodynamic centre of an aerofoil
132 views

### Can a commercial airline pilot, flying either A320 or B737, charge people for a flight in their own personal Cessna 172? [closed]

Or would they have to be some registered business for the industry?
302 views

### Why are the engines of the Airbus A400M slightly tilted down?

Picture: Youtube. Firstly, are the engines really tilted down? I have tried to check another picture over the net, seems they are really tilted down slightly. But need confirmation from you experts, ...
246 views

### Why couldn’t Boeing just use the stab trim system to do MCAS job?

If I’m incorrect in the question, please correct me. From what I’ve read and gathered the stab trim system essentially did the same before hand? It relies on AoA? And if so, did the computer for that ...
283 views

### What are ATC-side procedures to handle a jammed frequency?

A few days ago, I was flying into my base airport in the USA with a control tower, and something/someone was jamming the frequency with what the tower thought was a hot mic after I had established ...
126 views

### Could higher aspect ratio actually reduce gliding efficiency of a smaller glider?

I have been building 1 meter wingspan 100g class free flight mono wing gliders with a chord of around 10 cm and a flying speed of approximately 3 meters per second. So far glide ratios of around 10:1 ...
3k views

### What is the white pattern on trim wheel for?

On a A320, there are white patterns spread regularly on the trim wheel (highlighted on the right of the picture). First I though it was to have visual feedback about THS (trimable horizontal plane) ...
166 views

### Why did this old Japan Nakajima J1N airplane use a Yagi rather than a parabolic antenna?

Picture source. As per my understanding, a Yagi antenna is a directional antenna with limited gain, which it broadcasts or receives the microwave signal to and from the front side. It can only ...
142 views

### Does the AOA and G-Force increase if a fighter uses the afterburner during a max G level turn?

My understanding is that if you apply power (increase the thrust) for a jet in level flight, it will momentarily pitch up, and then gain some speed. So, if a fighter pilot lights their afterburner ...
148 views

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

Picture is from here. Is any other force to lift the V22 other than its rotors? Is any possibility that the power plants their self are not generating thrust? I was just wondered that such short ...
176 views

### What is the purpose of the vertical splitter and the NACA duct at the MQ-9 Reaper engine scoop?

The engine scoop/intake on the MQ-9 features a vertical splitter at the inlet face, as well as another smaller NACA duct on the top cowl surface just aft of the inlet lip. I am guessing the former ...
179 views

### Can a 737 be on final at 160 knots, and also touchdown at 160 knots?

Would the 737, going 160 knots, float a bit more before touching down?
55 views

### Are monoplane struts under tension, doubling the stress limit of the spar? [closed]

Are monoplane struts under tension, doubling the stress limit of the spar? If monoplane struts are under tension, they would be pulling the wing down, which would put the bottom of the spar under ...
80 views

### What happened to EC-ATQ?

EC-ATQ was a Douglas DC-7C. It was damaged beyond repair on 2.10.1970 in Madrid. Does anyone have more information? Was a piano dropped on top of it and nobody was willing to take the blame?
2k views

### Do wheelchair-accessible aircraft exist? [migrated]

I'm disabled and am restricted to an electric wheelchair. I cannot walk at all, and cannot sit in any other chair. I use a ramp van to get around town. It's just a regular van with several seats ...
65 views

### What official government document should a pilot check to determine what magnetic north a VOR was set to when it was commissioned?

Today I learned that VOR stations are all set to magnetic north at the time of commission, and since magnetic north moves, the VOR is not necessarily in-line with magnetic north in the present. Where ...
73 views

### Why do both east and west isogonic lines tilt toward the west as they go north?

Here is a picture of the 3 degree east isogonic line just north of Tulsa, OK. Here is a picture of the 4 degree west isogonic line just east of Nashville, TN. They both trend westward in relation to ...
39 views

I am an American Expat who got my EASA PPL(A) license while living abroad. I am about to move back to the US and looking into a permanent conversion to an FAA license. Per I have a European EASA ...
293 views

### What is the device at the tail of the F-16 Block 60?

The F-16 Block 60 has a lot of advancements, one of which is the device at the tail. What is it? For clarification, I believe all these vents (second image) are for said device.
3k views

### How do pilots align the HUD with their eyeballs?

In fighter jets, how do pilots align the HUD with their eyeballs?
7k views

### What exactly did this mechanic sabotage on the American Airlines 737, and how dangerous was it?

An American Airlines mechanic sabotaged a 737 in Miami An American Airlines mechanic accused of sabotaging a navigation system on a flight with 150 people aboard at Miami International Airport was ...
44 views

### On the ICAO Flight Plan Form, does /S replace O, V, and L?

I know the S stands for standard equipment (VOR, ILS, VHF radio). Is the format like G/S (GPS with standard equipment), or does the /S not imply coverage of the other line items, i.e., VLGO/S?
75 views

### Will a self balancing wing using an Eppler 186 airfoil still generate a Clmax of about 3+ with slats and slotted flaps?

Will a self balancing wing using an Eppler 186 airfoil still generate a cl of about 3+ with slats and slotted flaps? Although the NACA2415 used in the pegasus wing for the Zenith 701 has a low Cm, ...
78 views

### Why is the horizontal stabilizer of the Lazair swept back? [duplicate]

Why is the horizontal stabilizer of the Lazair swept back? I understand the hinged elevators are perpendicular to the fuselage, but the horizontal stabilizer is actually swept back.
374 views

### Was the oxygen mask, on this flight, out of order?

Recently I was on flight where the panel for the oxygen mask, above my seat, looked like on the picture: the "button" in the middle of the panel was extended, turned and was showing a red tag on the ...
168 views

### Why is an F22 slower than an F15?

An F22 has a higher thrust to weight ratio. The F22 has around ~70,000lbf thrust from its F119 engines, where as the F15 has around ~48,000lbf thrust from its F100 engines. But every metric I can ...
48 views

### When does the 18-month time limit begin for the JAR ATPL examination?

Here is an extract from JAR-FCL 1 concerning the period during which it is necessary to pass 14 ATPL exams: Subject to any other conditions in JARs, an applicant will be deemed to have ...
69 views

### In terms of communication with a computer with the receiver in a glider, is there a certain frequency I should consider? [closed]

I am part of a university team of engineers that design and manufacture a plane. My sub-team is in charge of designing an autonomous glider that needs to deploy from the plane and land in a given zone....
2k views

### Is it right to extend flaps only in the white arc?

If the cruise speed is >80kts on the downwind leg but I can only extend flaps in the white arc, am I right in saying I need to get to the white arc, even if I'm on - for example - 100kts? For ...
191 views

### Is it safe to fly with a B737-800? Is it different from a B737 Max 8? [duplicate]

I'm flying from Costa Rica to Chile in November with a B737-800 plane. I'm wondering if this is a different aircraft than the B737 Max 8 or if it's the same?
175 views

### What is the Angle of Attack of this Propeller?

Photo 1 and photo 2 from here, photo 3 is from here. Here are three propellers. As in my understanding, the AoA or the pitch of a propeller should be close to its rotation's direction, around 15 ...
156 views

### Why is the center of pressure of a rocket at its centroid?

From thin airfoil theory, at subsonic speeds, the center of pressure of any uncambered airfoil is at quarter chord. For sounding rockets, however, the center of pressure is generally assumed to be ...
3k views

### Why is the missed-approach course for the “RNAV (GNSS) - A” approach to runway 28 at ENSB shaped all funny?

Svalbard-Longyear (ENSB) has one particular approach (the RNAV (GNSS) - A approach to runway 28) whose missed-approach course is... oddly-shaped, to say the least: (PDF by Avinor; screenshot and ...
89 views

### Justification for the 2D cut-out method for determining a rocket's center of pressure

I've seen several tutorials on rocket stability where one can empirically obtain the center of pressure by cutting out a 2D imprint of the rocket and balancing the 2D shape as seen in the pictures ...
186 views

### What did this ATC call mean?

Audio Clip There is a rwy 24 in this airport. I'm not sure but the aircraft callsign likes 'TBN3BV'. I tried to find what the aircraft type is but I couldn't. Does somebody know what type of aircraft ...
99 views

### What’s the purpose of this trap door? [duplicate]

What’s the purpose of that trap door which is located at the end of the airplanes?enter image description here
106 views

### At what point does the throttle control RPM on a constant speed prop?

On an airplane with a constant speed prop, the prop lever typically controls the RPM (pitch) of prop, and the throttle controls the power, measured as Manifold Pressure ("MP"). However, at low power ...
42 views

### Calculate parasite drag coefficient from drag polar

The drag polar of an electric-powered unmanned aircraft is $$C_D = 0.038 + 0.0458 C_L^2$$ What is the parasite drag coefficient?
57 views

### What area is used to determine the horizontal and vertical tail volumes of a vtail?

What area is used to determine the tail volume of a 45 deg vtail? Is the same entire area of the vtail used to calculate vertical and horizontal tail volume? or do you use the projected areas in the ...
53 views

### How to choose an angle of incidence?

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 ...
9k views

### What can a pilot do if an air traffic controller is incapacitated?

I watched this video: where a Las Vegas controller is on duty alone and suffers a stroke. The pilots become quite uncomfortable with the situation and basically ...
3k views

### Why there so many pitch control surfaces on the Piaggio P180 Avanti?

Picture source. I have seen that there is kind of sonic aircraft like B-1B Lancer that used elevator and canard or fins at the same time for pitch control. That quite understandable because it is ...
151 views

### What's the difference between a “flight line” and a “tarmac”?

I was at a conference where there was a discussion on ontology for assets. There were two classification trees, one for assets on the flight line and one for assets on the tarmac. What is the nuance ...