# All Questions

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15 views

### Can climbing above RVSM airspace cause temporary loss of separation with an aircraft in RVSM airspace?

Consider Aircraft A cruising at FL400 and Aircraft B cruising at FL410. Both in close proximity, heading in the same direction. Ignore altitude for direction of flight issue. When aircraft B requests ...
37 views

### How calculate water rocket thrust?

both nozzle is 2cm diameter one "rocket" has air pump which hold constant 5 bar second "rocket" it has water inside and also air pump which hold cosntant 5 bar,(water column is ...
47 views

### When flying on a glide slope, does the G meter show 1G or less?

If your angle of attack in landing pattern is 14 degrees but your vertical velocity is 600 feet/minute, does the HUD show you 1G or not? Why?
66 views

### What are the names of the antennas which I have marked in this picture of a Boeing 737?

I have taken the picture from PMDG 737NGX Microsoft flight simulator X. I am really curious to know what this antennas are. These antennas are behind the nose gear.
50 views

### Does DA/DH refers to ceiling?

If airport is reporting FEW001 or SCT001 and RVR is above 600m, does it means that there will be no LVO because ceiling is defined as more than 4/8 and DA/DH will be more than 100ft because DA/DH is ...
53 views

### What is the difference between ILS and VOR/DME?

I have wondered many times about the difference between VOR/DME and ILS and which one is better for carrying out approaches. Why do pilots use VOR/DME when the ILS is a better option because it is ...
172 views

### A jet engine's shaft is neutral in the direction of thrust?

I think I read somewhere that the forces on a jet engine shaft is neutral because the forces at the turbine and compressor cancel out. This means that the axial bearings don't have force on it in ...
98 views

### Other than the 747, are there any other current, recent or planned airliners with a nose door option?

Boeing has recently announced that the 747 program is coming to an end. One of the key features of the freight 747s was the nose door, which facilitated faster loading of freight and allowed the ...
60 views

### What is relation between Reynolds number-turbulent flow-flow separation? [duplicate]

can some explain conection betwen re number -turbulent flow -and flow separation ,in example at wing in the air and water? 1)does high numbers= turbulent flow mean higher resistance to flow separation ...
20 views

### Why is hybrid laminar flow control preferred for swept wings over other options?

As I understand it, a (the?) major form of laminar-to-turbulent transition on the swept wings of large jets is the crossflow caused by the sweep. One way to control this is laminar flow control by ...
143 views

### Is/why isn't the Antonov 124 to 225 wing upgrade method common?

I'm told that wing redesigns (edit: for tapered, swept wings) are difficult, so variants of a model often do with a common wing optimized for the middle member. But then I read the following: Based ...
39 views

### Why does a steady-state non-zero body yaw and/ or roll rate induce side force?

An answer on ASE states The presence of steady-state non-zero body yaw and roll rate induces side force ($C_{y_p}$ and $C_{y_r}$). What is a non-mathematical explanation of why this is so? Is it ...
1k views

### What is this “Supersonic French” aircraft?

To celebrate Bastille Day, Ubisoft released the below (2D) in-game charm for their game, Tom Clancy's Rainbow Six Siege. Despite frantic searching on Wikipedia, I cannot for the life of me figure out ...
381 views

### Why does the UK CAA restart its page numbering with every new chapter of their CAP publications?

Every CAA Publication (CAP) seems to restart its page numbering when starting a new chapter. Does anyone know why they have decided to do this? For example, the CAP413. Instead of a logical page ...
33 views

### How does wing shape impact shock structure?

I am trying to understand what the 3D shock structure would be for a wing in supersonic flow. Suppose we have a wing which is made of double-wedge airfoil cross-sections. If we view the shock ...
146 views

### Is PVC tubing a good material for helicopter airframes?

Been thinking of getting into the hobby of building ultralight helicopters, and would PVC tubing be a good choice to build the overall airframe?
85 views

### CH-37 Mojave Helicopter decibels

What was the decibels level for the Sikorsky CH-37 Mojave Helicopter? 1956 --1959. I need this information for the VA, to process my hearing claim. I was a crew chief in the Army.
212 views

### Can Airbus A320 doors be opened mid-flight?

Today I learned how airliner doors are typically an outward facing plug and cabin pressure would make them nearly impossible to open mid-flight. It's easy enough to see that for the shape of Boeing ...
67 views

### Does the strength of a wingtip vortex generated by an airfoil peak at the critical angle of attack?

I know that generally, wingtip vortices increase in strength as the angle of attack increases. Is the critical angle of attack/Cl Max the peak strength, or do the vortices generally continue to ...
5k views

### Are there any remaining flying boat or seaplane airliners in operation?

Is there anywhere in the world that still offers scheduled air carrier service using flying boat / seaplane types of aircraft - something akin to a proper airliner? Or are they all limited to charters ...
95 views

### Is there a 'common courtesy' distance that should be complied with when initiating contact with ATC for class D airspace?

Some background: I'm a student pilot preparing for an upcoming stage check involving XC diversions and have been trying to visualize different scenarios of what I'd need to do when diverting. One case ...
968 views

### What is this thing on a FDX MD11 (MD10?)?

I assume something forward looking; not sure why there and how they got this to play nicely with radar
245 views

### Is it feasible to replace a C152's engine with multiple small turbine engines?

If I wanted to remove the piston engine from a cheap plane like a Cessna 152 and add small turbine engines with an equivalent thrust but weighing less, where would be the best place structurally to ...
86 views

### Why does a banked aircraft create sideslip?

Below is an excerpt from Raymer (Aircraft Design) where he explains the dihedral effect. He states that a banked aircraft (due to say a roll disturbance) will have a sideslip which leads to a ...
86 views

### RC airplane required engine power

I'm going through the process of designing an RC airplane. I know that probably most calculations on scale models might be non-precise ones, but I'm trying to do it as correct as possible (it's a ...
44 views

### Are AWOS data open for commercial use? [closed]

I 've found out this great website where you can get historical AWOS weather data. I would like to use it for a commercial application but I don't find any data license. Do you know if the AWOS data ...
189 views

### Can airplanes benefit from this “roughness” on bird wings?

Why do birds have so much rough surface (overlapping feathers) compared to aircraft? Isn’t that cause additional skin friction drag? Could planes maybe benefit from this? link: https://www....
121 views

### Can an Unserviceable Component be fitted on a Serviceable Aircraft for Maintenance Check

I was doing some reading on aviation regulations and I wanted to understand from an expert whether the following situation is allowable or not. I have reviewed EASA Continuing Airworthiness Guidelines ...
4k views

### Do aircraft at cruise bob and/or skip?

Recently I started flying a model aircraft, admittedly a kindness for a motor stuck onto a piece of foam, and have noticed that it either bobs, for lack of a better term, like something afloat on ...
54 views

### Are there freely available Arinc 429 data? [closed]

Would like to ask if anybody knows there is freely available Arinc 429 data on line? If not, is there any company that sell them? thanks
156 views

### Ventral masts- what are they?

I have kids working on a model of a Boulton Paul Defiant, a WWII-era fighter plane. When we found images of this plane, it shows two rods sticking vertically down from the belly of the plane. Some of ...
124 views

### How controllable is the 737 in single-engine manual-reversion flight? Is it controllably landable (or go-around-able) in this condition?

The 737 is practically the only civilian jetliner still in production1 to have provisions for flight-control manual reversion; in the event of a total failure of the A and B hydraulic systems, the 737’...
31 views

### kinetics of particles [closed]

a jet aircraft climbs in a straight line at an altitude of 60 degrees to the horizontal. the jet thrust amounts to 90 KN, the mass of the aircraft is 8000 kg and the average air resistance amounts to ...
58 views

### Where is there an FAA source that states that squall lines are non-frontal?

There's a question in the FAA commercial question bank that indicates that squall lines are nonfrontal, and the reference for the question points to the Aviation Weather Advisory Circular. The word, &...
50 views

### How can the (e)VTOL certification processes be harmonized? [closed]

Despite the harmonization efforts on new Part 23/ CS-23 by the EASA and the FAA, it seems that both authorities are taking a very different path to certification for VTOL. The EASA released a Special ...
247 views

### Why does turbofan exhaust appear to reverse direction?

Yesterday I was at the airport planespotting. I observed the exhaust of a couple of turbofan engines, and found it curious how the fluid seemed to behave as it was leaving the engine and gaining ...
57 views

### Aircraft fuselage [closed]

Are they anyone that knows about carbon-epoxy fibre composites as fuselage ? I have read about Boeing 787 dreamliner fuselage but couldn’t find anything useful there.
171 views

### What would happen if a hot air ballooon was punctured in mid-air?

I am writing a script for a film where a hot air balloon is punctured and it falls to the ground. There are two teenagers in the balloon when it is in the air. What I would like to know is how fast ...
9k views

### What could explain the fact that during 1976-80, I used to hear commercial jets make sonic booms while flying overhead?

I've read on this site & on Wikipedia that there have only been a couple of commercial jet planes in history that have broken the sound barrier--either in testing (without passengers) or during an ...
90 views

### Why is CL/Cd equal to L/d?

I'm making a school project where I intend to design and calculate an rc airplane. Reading some books I found something I can't understand, it says that CL/Cd is equal to L/d, but the only possible ...
298 views

### How do I obtain permission to fly in surface class E airspace under FAR-103?

I'm a paramotor pilot operating under FAR 103, and I'm trying to determine who I need to ask for permission to fly in class E airspace that extends to the surface and is designated for an airport. For ...
154 views

### What does 'EST' at the end of a NOTAM's valid time mean?

In this NOTAM below, the valid time is "2006280446-2007312359EST". EST does not appear in the FAA NOTAM contractions list. I assumed this EST meant "Eastern Standard Time", but ...
90 views

### Does flutter disappear above the flutter speed?

Okay, lets assume we have an airplane with some sort of superstrong wing, but otherwise conventional configuration. We accelerate it gradually. Eventually, it will reach flutter speed, at which the ...
129 views

### How feasible is a nuclear powered lighter-than-air vehicle that uses steam as the lifting gas?

An interesting question was asked regarding the use of steam as a lifting gas for lighter-than-air vehicles here: What are pro/cons of steam as lifting gas for airships?. Many of the challenges with ...
1k views

### How are flight hours counted?

I was watching a presentation from a software developers' conference in which the presenter went through the steps leading to the crash of United Airlines Flight 232 to make a point about Crew ...
41 views

### What are the most common professional software for aircraft design and aerodynamic/stability analysis? [closed]

What are the most common professional software (free if possible & user friendly) for aircraft design and aerodynamic/stability (static & dynamic) analysis? I recently designed my aircraft ...
4k views

### Do pilots keep light in the cockpit during long night flights?

During long times of the cruise flight, is the internal light normally switched on or off inside the cockpit? Knowing it is generally dark in the night would make a smartphone-based night time logger ...
62 views

### Can I count solo complex time as complex training time for a commercial certificate?

Does a combination of both dual and solo hours in a complex aircraft (PA28R-180) which total 10 or more flight hours meet the commercial pilot training requirements of FAR 61.129(a)(3)(ii) or must all ...