46
votes
Accepted
Why was this commercial jet accompanied by small plane near Seattle?
It's a Fedex 777F N894FD in (probably) pre-delivery aerial photography/test flight accompanied by one of Boeing's chase aircraft.
After some maneuvers (shown below), the plane headed to MEM, Fedex's "...
- 3,797
45
votes
Accepted
Why doesn't GE replace all 4 engines for on their flying test bed instead of just 1?
They only change one, because that one is a new engine that is being tested.
If you are testing a new engine you change 1 at first so if it fails you have 3 others. If you change all 4 and there is ...
- 35.1k
43
votes
Accepted
Can supersonic conditions be replicated on the ground?
Yes, supersonic conditions can indeed be replicated on the ground for purposes of airframe and engine testing.
Arnold Engineering Development Complex (AEDC)
The U.S. Air Force and NASA both operate ...
- 19.1k
39
votes
Accepted
Why do uncontained engine failures still occur?
One of the absolute requirements of an aircraft turbine engine (usually some sort of turbofan or turboprop) installation is that, in the event of a destructive failure of the engine, the engine ...
- 55.5k
36
votes
Accepted
Are test pilots certified to fly all aircraft types?
Since you didn’t specify a jurisdiction, I’ll answer for the FAA. Others should be similar.
Pilots must be rated for the category, class and (if applicable) type of aircraft. Category is pretty broad, ...
- 27.3k
34
votes
Can supersonic conditions be replicated on the ground?
It is a struggle, but it can be done. For the J58, Pratt&Whitney had a test facility at West Palm Beach which would simulate conditions at speed and altitude. From this site:
The picture ...
- 225k
34
votes
Accepted
For what program was this Cessna 182 fitted with canards?
It's a King Katmai STOL mod for a Cessna 182. From https://www.avweb.com/ownership/king-katmai-mod-safe-stol/
The full King Katmai modification consists of the canard, 300-HP IO-550, choice of 82- or ...
- 39k
33
votes
Accepted
What is the purpose of the black and white stickers on test aircraft?
They appear to be fiducial markers which identify known points on the aircraft, for analysing video footage and performing photogrammetry.
You see similar markers on crash-test dummies used in vehicle ...
- 1,050
29
votes
Accepted
Did I witness an engine test for a 757 at MAN?
See this avherald report: https://avherald.com/h?article=4db1ccdb&opt=1
A Jet2.com Boeing 757-200, registration G-LSAN performing a test flight from Manchester,EN to Manchester,EN (UK), was in ...
- 12.6k
27
votes
How do test pilots determine an aircraft's capabilities?
Short: The pilot has a well-defined range of discretion within progressively increasing bounds very tightly set as part of a structured development program aimed at eliciting maximum information ...
- 1,434
26
votes
Why do we complete wing bending tests?
Transport category airplanes, which includes most aircraft in commercial passenger service, must meet the FAA regulations in 14 CFR Part 25. Some relevant excerpts are as follows:
§25.305
The ...
- 70.5k
26
votes
Why was this commercial jet accompanied by small plane near Seattle?
It looks like an air-air photography trip by Boeing - the lead airplane is a LearJet, a type often used for this type of job with a turreted camera sticking out of the floor for views to the rear, ie ...
- 4,532
21
votes
Accepted
Why are these windows on some airplanes red?
A red/orange color is typically used to denote flight test instrumentation. Indeed, these windows do contain such instrumentation. Below you can see a similar window on a 747-8I flight test aircraft (...
- 3,113
19
votes
Are test pilots certified to fly all aircraft types?
I worked as a test pilot for my aerospace employer. I have a small collection of ratings, and for unusual operations, and for experimental equipment operations we use Letters of Authorization (LOA). ...
- 17.6k
19
votes
Accepted
What is that little black thing tied to the vertical stabilizer?
That’s a trailing cone. It hangs out behind the aircraft and serves to calibrate the aircraft’s pitot-static system against static pressure error by providing a static source for ambient air ...
- 2,464
17
votes
Accepted
What is the purpose of the ball and string attached to the tip of the vertical fin on test aircraft?
That is a static pressure line. The "shuttlecock" device on the end pulls the line out behind the aircraft, where it can get a more accurate pressure reading, away from the air flowing around the ...
- 70.5k
16
votes
Accepted
Could a test crew replicate the 1961 DC-8 supersonic dive in a more modern airliner?
Why not?
There have been several cases of near-sonic and even supersonic dashes by the Boeing 747, and the damage to the China Airlines Flight 006 elevator was done by landing gear doors which ripped ...
- 225k
15
votes
Why are airports like Roswell and Fresno so popular for flight tests?
You can do flight tests from almost any airport, but it helps if:
The weather is dry and stable,
the field is not too far from the factory,
there is a large unpopulated area nearby, and
you have ...
- 225k
15
votes
How did the US get the necessary knowledge to maintain their MiGs?
Its a combination of those. US did have manuals for quite a few of the Migs- Cold war alliances were shifting too frequently to prevent any leak of military technology. As warisboring.com notes:
...
- 99.4k
14
votes
Accepted
How does ATC control / separate Airbus Industrie test flights?
They will be in contact with ATC at all times and ATC can issue a clearance to operate within a defined area or within a specific flight level range, keeping other aircraft out of that area, e.g.
...
- 15.6k
14
votes
Accepted
Why do we complete wing bending tests?
It ensures that the theoretical assumptions are correct in practice.
Therefore it save our lives.
- 1,135
13
votes
Accepted
What is the purpose of flutter testing?
Flutter is a phenomenon that can occur when a structure is subjected to aerodynamic forces. It occurs not only in aircraft but also for example in buildings, power lines, road signs and bridges. ...
- 77.1k
13
votes
Can supersonic conditions be replicated on the ground?
As shown here, Lockheed Martin has a supersonic wind tunnel capable of generating wind speeds of up to mach 5. A quick Internet search revealed an extensive list of other supersonic wind tunnels, ...
- 2,723
13
votes
Why do uncontained engine failures still occur?
It's been pointed out that a single blade may be contained, but having a whole stage fail is an extremely high energy event. The high speed spool of a turbine engine is spinning at 10's of thousands ...
- 70.5k
12
votes
Why are these windows on some airplanes red?
The aircrafts shown above are test aircraft and the windows are blanked for mounting test instrument. The image below shows the inside of Bombardier C-series test aircraft, which shows the mounting of ...
- 99.4k
12
votes
Why doesn't the 747 that is testing the GE9X have winglets?
That's because its been removed for testing. The aircraft used in for flight testing the GE-9X belongs to GE and is a modified JAL 747-400.
The aircraft, a former Japan Airlines -400, was acquired ...
- 99.4k
11
votes
Are there safety countermeasures for test flights that simulate crashed flights?
The test was flown on a DC-8-72. This model aircraft is certified to have its inboard thrust reversers deployed during flight, which means that the test was either within standard operational ...
- 4,193
10
votes
Accepted
How are special flight paths coordinated with ATC?
Rules for ATC in the US are laid out in FAA JO 7110.65.
The primary purpose of the ATC system is to prevent a collision between aircraft operating in the system and to provide a safe, orderly and ...
- 70.5k
10
votes
For what program was this Cessna 182 fitted with canards?
Terry got it right! It’s a King Katmai STOL Kit. You can practically squeeze that thing into a parking lot!
- 69.4k
Only top scored, non community-wiki answers of a minimum length are eligible