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23
votes
3 answers
What is this smoke coming from an F/A-18 shortly before takeoff?
Watching a video of F/A-18 fighter-jets taking off, I noticed some sort of gas blowing out behind the canopy shortly before the start of the takeoff roll.
Here's a screenshot:
In some videos the smoke is more dense than in others. Has this…
jklingler
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23
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How does the A350/380 operate on Variable Frequency AC generators?
To keep a constant frequency of 400 Hz, most aircraft have a CSD (Constant Speed Drive) associated to the AC generator. On most types (e.g. A320, A330, B737, B747, B777) an Integrated Drive Generator (IDG) is used. This unit is simply a CSD and an…
Gianni Alessandro
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23
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Could a knowledgeable passenger have saved Helios Flight 522?
Helios Flight 522 crashed when the crew unknowingly suffered hypoxia. Although the masks in the passenger cabin deployed, the crew were unaware of this and didn't realise the extent of the problem.
If I was a passenger on a plane at cruise…
David Glickman
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What is the reason for changing the speed reference (IAS or Mach number) with altitude?
Inspired by that question: How is the airspeed-Mach number transition handled in modern airliners?
When pressure and density decrease IAS also decreases. When temperature and pressure/density decrease speed of sound also decreases. As air pressure,…
mins
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23
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4 answers
Why not have Pitot Heat always on?
Most (all?) aircraft have a Pitot Heat Switch which must be turned on in certain conditions.
Seems Pitot Heat is one of those things you don't want to forget to switch on when it's needed, or worse, not recognize you need it on and take action based…
SnakeDoc
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23
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2 answers
Taxiing with one engine: Is engine #1 always used or do they switch?
I recently travelled with an A320 and an A321 from FRA (Frankfurt) to TXL (Berlin) and back again. On this and on previous flights I already noticed a whining sound, much louder than other sounds, while we were still at the gate or soon after…
PerlDuck
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23
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2 answers
How would you brief passengers who will try flying your plane?
Following up on this question about pilots letting passengers fly the plane, suppose you’re in a Cessna 172 with passengers and you have your PPL. If you want to let a friend try flying the plane, you might climb to 3,000' AGL and get clear of other…
Peter
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23
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Which civilian airport has the most runways (current and planned)?
I just read Is the airport capacity related to number of runways? . While there are a host of factors, the idea of more runways is obviously so that more flights come in and out. Which is the biggest and baddest airport which has the largest number…
shirish
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4 answers
Which aircraft require that the vertical position of the centre of gravity is checked?
We normally check the aircraft CG along the longitudinal axis and the lateral axis (sometimes referred to as the transverse axis) to ensure it is within limits. Until recently I was unaware of any aircraft that required a check and control of the CG…
Terry
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23
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2 answers
What are those trucks towing around, and why?
I was in Prague airport and saw those things going around:
As for title, what are they towing and why? I can imagine it could be to alter airport layout, but I don't see a use for it.
Sub question for and additional answer's virtual bonus: is it…
motoDrizzt
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1 answer
Under VFR, can a pilot fly above a layer of clouds?
Image source
I often see charts like the one above showing VFR cloud clearance minima. Since the regs list a minimum distance above clouds obviously VFR flights are allowed to fly over clouds. However, it's not clear what kind of clouds one can fly…
TomMcW
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23
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3 answers
Where did the standard pressure 29.92" come from?
Below the transition altitude (18,000 feet in the US), pilots use local pressure readings to calibrate their altimeters.
Above the transition altitude, pilots set a standard pressure to calibrate the altimeter. The standard pressure is 29.92 inches…
fooot
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23
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What level of damage to an aircraft is acceptable to let it depart?
Yesterday (28 June 2016), a Bombardier Q400 from EPGD to EPWA made an emergency landing because of a blown tire, spotted by a passenger. Everything went smoothly and the plane landed successfully assisted by fire trucks.
You can see the article and…
Mark
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23
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4 answers
What scientific evidence is there about the effectiveness of pre-flight walk-arounds?
As a student pilot, often on my walk-around, I get the impression that there are any number of hazards that could pass me by, simply because I can look at every part on the checklist but I wouldn't necessarily recognise a problem with that part.…
Dan Hulme
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How did planes measure their speed relative to the ground before GPS?
How did planes measure their ground speed before GPS?
If they used some sort of anemometer to measure speed, that would only measure the speed of the plane relative to the air through which it is passing.
Therefore, I'm wondering how speed relative…
Pat
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