gopal
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Are Planes Test Flown?

Fri Aug 20, 2004 12:49 am

After a A/C is manufactured, is it test flown before it is delivered to the customer ? Or is all the testing is simulated. Integrated testing of an aircraft must be a very complicated procedure. For example, engines might work fine in the lab, but once fit under the wings of a 777 (for example), they need to tested to ensure that they produce the right amount thrust and all the backup systems are working with the other systems on the airplane.

I would appreciate information on the various testing that an aircraft has to undergo before being delivered.
 
SlamClick
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RE: Are Planes Test Flown?

Fri Aug 20, 2004 1:15 am

Yes they are.

My information is dated and purely secondhand but I have seen (from the ground) flight testing by Boeing, Douglas, Embraer, Bell and North American.

As of the late 1970s, the MD-80 and DC10 program went something like this. When an airframe was rolled out, complete, the flight test crew would take posession of it. They would fly one test flight, originating in Long Beach (LGB) and terminating at Yuma Arizona (YUM) There were up to three factory test flights programmed, called D1 through D3, then the plane was turned over to the customer for flight tests C1 through C3 (C for Customer)

If trouble developed, I suppose more flights could have been added. If all went really well, I don't know if the program could have been shortened. Flight C3 began at YUM and terminated at some city in the customer's route structure, where, if all had gone well, a regular passenger flight was already scheduled for that plane.

The planes were delivered out-of-state because California had very high sales taxes. Think what one percent or so on the ticket price of a DC-10 would amount to. California has deep financial troubles because of their ill-considered tax laws.

Anyway, that was the system at the time, according to an acquaintance who worked at McDoug.

As you point out, things can go wrong. They are extremely careful and professional in the manufacture of these aircraft, but they are staggeringly complicated. The test flights are conducted according to job cards that test each system as thoroughly as is practicable.

I'd be interested in hearing from anyone with more recent, in-depth, or even more correct information.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
airplay
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RE: Are Planes Test Flown?

Fri Aug 20, 2004 1:25 am

Yes aircraft are test flown and all snags are cleared to the customer's satisfaction before it is officially delivered.

This should not be confused with the certification flight testing that goes on with new designs.
 
citationjet
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RE: Are Planes Test Flown?

Fri Aug 20, 2004 1:58 am

EACH plane coming off the production line is flown to a Flight Functional Test Plan. These test plan documents are over 50 pages for a small business jet. This flight testing is production flight testing, and not certification flight testing (for obtaining Type Certification of the new design). These production flight tests verify that each production airplane conforms to type design. At Cessna, these flight tests are done by production test pilots, not engineering test pilots or marketing test pilots.
Any squacks are written up and corrective action taken before customer delivery.
A small Citation will typically have less than 10 hours on it at customer delivery. A larger Citation (Citation X) will have less than 15 hours at customer delivery.
Boeing Flown: 701,702,703;717;720;721,722;731,732,733,734,735,737,738,739;741,742,743,744,747SP;752,753;762,763;772,773.
 
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Starlionblue
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RE: Are Planes Test Flown?

Fri Aug 20, 2004 2:04 am

Before the test flight, Boeing also "fly" the whole plane on the ground (at least the 777). Basically it's set on struts so the gear can retract. Then they "trick" the software into thinking that the plane is in the air with engines running and "fly" it around for a whole flight, including retraction and extension of surfaces and gear.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
citationjet
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RE: Are Planes Test Flown?

Fri Aug 20, 2004 2:12 am

Starlionblue is correct.
Prior to flight testing each production aircraft, a series of ground functional tests are performed during the production process. These tests include systems performance (electrical, hydraulic, environmental, avionic, propulsion, etc), fuel quantity indication calibration, control system checks, engine ground runs, plus many others. These have to be completed prior to the first flight.
Boeing Flown: 701,702,703;717;720;721,722;731,732,733,734,735,737,738,739;741,742,743,744,747SP;752,753;762,763;772,773.
 
Dalmd88
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RE: Are Planes Test Flown?

Fri Aug 20, 2004 4:31 am

We even give planes a 'test flight' after completion of a 'D' check or overhaul.
 
Dufo
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RE: Are Planes Test Flown?

Fri Aug 20, 2004 5:29 am

Regarding these 'ground flights' on jacks.. do these tests involve artificial pitot-static data?
I seriously think I just creamed my pants without any influence from any outside variables.
 
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Starlionblue
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RE: Are Planes Test Flown?

Fri Aug 20, 2004 5:58 am

I'm guessing yes, since that would be the easiest way to fool the rest of the plane that it is at altitude.
"There are no stupid questions, but there are a lot of inquisitive idiots." - John Ringo
 
citationjet
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RE: Are Planes Test Flown?

Fri Aug 20, 2004 7:29 am

You have to be careful when you fool the airplane when testing it on jacks. Here is what happened to a Gulfstream V:

Mechanics Blamed for GV Hard Landing
On February 14, 2002, about 0649 eastern standard time, a Gulfstream Aerospace G-V, N777TY, operated by BBFive Inc., as a Title 14 CFR Part 91 positioning flight landed hard at West Palm Beach International Airport (PBI), West Palm Beach, Florida.
According to the NTSB, General Dynamics Aviation Services maintenance personnel in Palm Beach, Fla., failed to remove popsicle sticks that were being used to disable the weight-on-wheels (WOW) switches of a Gulfstream V on jacks. That led to a hard landing causing substantial damage to the airplane, according to the NTSB’s final report of the Feb. 14, 2002 incident. Shortly after departure, the pilot requested a return for landing because the landing gear would not retract. As the jet flared for landing and the crew pulled back the power levers to idle, the spoilers deployed because of the disabled WOW switches. Flight data recorder information showed that the spoilers deployed when the airplane was nearly 60 feet high. The airplane hit the runway at a vertical acceleration of 4.25 g, driving the right main gear through the wing and rupturing a fuel tank. The aircraft, N777TY, was registered to BBFive, Wilmington, Del., and operated for Ty Inc., Oakland, Ill.


[Edited 2004-08-20 00:31:27]

[Edited 2004-08-20 00:32:54]
Boeing Flown: 701,702,703;717;720;721,722;731,732,733,734,735,737,738,739;741,742,743,744,747SP;752,753;762,763;772,773.
 
gopal
Posts: 167
Joined: Thu Jun 03, 1999 3:05 am

RE: Are Planes Test Flown?

Fri Aug 20, 2004 10:39 pm

Thank you all for providing such detailed informative answers.

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