comorin
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How Are Planes Tested After Maintenance Checks?

Sun Aug 21, 2005 7:06 am

I was wondering after an 'overhaul' (C or D checks, I believe), what do you do to make sure the plane is ready to fly? Do you actually take it out on the runway or take off? Or do you just assume it'll fly because it's been checked out so thoroughly? I can understand each unit (hydraulics, engines) can be tested separately without flight testing, but how do you assure that the whole thing works?

Thanks in advance...
 
LimaFoxTango
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RE: How Are Planes Tested After Maintenance Checks?

Sun Aug 21, 2005 7:51 am

How do you test your car after you've had it serviced? You take it out for a spin right? Well, it's basically the same principle here. Who actually does these kinda flights, well, I really dont know. I would guess senior pilots and maybe a few mechanics would be on the aircraft.
You are said to be a good pilot when your take-off's equal your landings.
 
tbanger
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RE: How Are Planes Tested After Maintenance Checks?

Sun Aug 21, 2005 8:18 am

After a C check is done on our Saabs, we schedule a "Proving Flight". It will consist of a flight crew (no specific experience or ratings) and a Lame or Queer trade in the observer seat.

Then usually new staff who have never flown before or just plane love to fly will go also. An Engineer or Apprentice will go through the cabin and load up the air gaspers, lighting, intercom speakers etc and also listen out for any pressurisation leaks or untoward rattles and creaks. (Note: Staff are covered by our company's insurance. Work experience kids and family are not).

These flights are no big deal really. Just because it is a C check, not much more gets done other than would happen on a regular "A Chck" or such. It just all happens at once during the C check.

Things like flight controls are checked well before the aircraft is allowed back in the air, but if you change say, the bellcrank bearings, then a test flight is well worth the ride. Steep climbs, steep turns, wing overs, zero G push overs, they are all great fun from row 11. (of course we have to try out the barf bags as well...no good if they don't work...hehehe!  vomit  Wink
 
MD11Engineer
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RE: How Are Planes Tested After Maintenance Checks?

Sun Aug 21, 2005 8:51 am

First, each component is checked by itself, then the different systems undergo operational and functional tests on ground. Certain avionics equipment will also have it's calibrations checked.
These are part of the regular work package, plus those tests as per AMM, which refer to components which have been found faulty during the check and accordingly been replaced.
When all ground tests have been finished successfully, the plane will after a heavy check be taken up by a test flight crew under a permit to fly for a test flight, where the systems are being checked again under flying conditions, e.g. the plane will do a autoland in good weather to check if the system works, or the plane will be intentionally depressurised above 14,000 ft to see if the oxygen masks deploy. The RAT will be deployed and usually such a flight ends with a gravity extension of the landing gear.

All ground tests will have been certified for by the respective mechanic or inspector who performed them (in Europe the JAR 66 B1 or B2 licenced AME), in some cases additionally by an inspector who did a duplicate inspection.
After the plane has been put back into flying condition after the flight test (e.g. RAT and oxygen masks stowed and all snags rectified), an inspector (in Europe a JAR66 C licenced AME) will sign the final release to service. From then on the plane is good for revenue operation.

Jan
Je Suis Charlie et je suis Ahmet aussi
 
EMBQA
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RE: How Are Planes Tested After Maintenance Checks?

Sun Aug 21, 2005 12:32 pm

I was wondering after an 'overhaul' (C or D checks, I believe), what do you do to make sure the plane is ready to fly?

It depends on what was done and what systems where worked on. Most all checks can be done from right inside the hangar. We'll do travel checks of flight controls and check the travel limits. Most airlines do list in their Operations Manual that if certain flight controls are changed, a flight test is requires. You do not always need to test fly after coming out of heavy check.

Steep climbs, steep turns, wing overs, zero G push overs, they are all great fun..

Full Stalls, Engine Shut downs... aah the good old days of flight test. I do miss it so..!!

[Edited 2005-08-21 05:38:47]
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
320tech
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RE: How Are Planes Tested After Maintenance Checks?

Sun Aug 21, 2005 12:41 pm

On the A320, we don't do a test flight after a C check - in fact, the aircraft leaves the hangar and goes directly to the terminal for a revenue flight. Sounds crazy, right? The number of turn backs over the last five years can be counted on one hand (with four fingers left over, I think).

On heavy checks, a test flight may be done, but generally isn't.

Do I need to say that the aircraft is thoroughly tested before it leaves maintenance?
The primary function of the design engineer is to make things difficult for the manufacturer and impossible for the AME.
 
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HAWK21M
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RE: How Are Planes Tested After Maintenance Checks?

Sun Aug 21, 2005 5:39 pm

Quoting MD11Engineer (Reply 3):

Also ROC v/s time is checked to claculate L/D ratio.In flt Engine Relighting & L/G Manual Deployment is carried out.Although same is also done in the hangar too.
Since our SOP states that after Each C Check or Higher a Flt test is Mandatory.The same is carried out.
Meanwhile most checks are done on Grd itself.
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
comorin
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RE: How Are Planes Tested After Maintenance Checks?

Sun Aug 21, 2005 11:08 pm

Thank you all for taking the time with the explanations! Wish they had tours of maintenance hangars for engineering enthusiasts. The closest I got was visiting the DC10 assembly line in Long Beach a long time ago...
 
troubleshooter
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RE: How Are Planes Tested After Maintenance Checks?

Tue Aug 23, 2005 5:46 am

Quoting Tbanger (Reply 2):
Lame or Queer

I do know what a Lame is, but what the hell is a QUEER???
This job sucks!!! I love this job!!!
 
tbanger
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RE: How Are Planes Tested After Maintenance Checks?

Tue Aug 23, 2005 6:43 pm

Troubleshooter: "Queer Trade" is what LAME's call "Avionics Technicians". At least in our Hangar anyway..

EMBQA: One of the advantages of being a small Regional Carrier (where everybody knows everybody) and having your Heavy Maintenance Facility stuck way out in the boon docks. (That's Aussie for "Out back of Bourke").

Stalls and practice assymetric flight is prohibited here unless the flight only has essential flight and ground crew neccesary to complete the flight. Basically 2 pilots and 1 LAME.
 
EMBQA
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RE: How Are Planes Tested After Maintenance Checks?

Wed Aug 24, 2005 8:27 am

Tbanger-

All of my flight test was in the Saab 340. It was always fun to go upo and do a full flighttest program. After the 4 hours of getting knocked around I was ready to get back to mother earth and drink a pint..!!!
"It's not the size of the dog in the fight, but the size of the fight in the dog"
 
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HAWK21M
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RE: How Are Planes Tested After Maintenance Checks?

Wed Aug 24, 2005 6:18 pm

Quoting Tbanger (Reply 9):
Queer Trade" is what LAME's call "Avionics Technicians

Out here We [A&P] call them the "cleancoats"  Smile
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
VC-10
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RE: How Are Planes Tested After Maintenance Checks

Wed Aug 24, 2005 8:31 pm

In my company air tests are only carried out if all engines and or a major control surface has been removed (and refitted Smile ).
 
MD11Engineer
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RE: How Are Planes Tested After Maintenance Checks?

Wed Aug 24, 2005 8:32 pm

For us they were 'lecies or Coneheads, somwtimes Sparkies. In LH they were called ERI's (Electrics, Radios, Instruments).

Jan
Je Suis Charlie et je suis Ahmet aussi
 
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HAWK21M
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RE: How Are Planes Tested After Maintenance Checks?

Wed Aug 24, 2005 8:52 pm

Quoting MD11Engineer (Reply 13):

They are more calmer & less Aggressive than us A&Ps.One can tell the Difference by look or their body language.  Smile
regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
MD11Engineer
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RE: How Are Planes Tested After Maintenance Checks?

Wed Aug 24, 2005 9:38 pm

Quoting HAWK21M (Reply 14):
They are more calmer & less Aggressive than us A&Ps.One can tell the Difference by look or their body language. Smile
regds
MEL

Erm, some at LH are very arrogant. They call the A&Ps "black hands", because we wave to touch oil and grease, and they generally assume that we are too stupid to understand avionics and electrics, we are only to be trusted with heavy spanners and grease. In the LH base in SXF, they didn't want to share a breakroom with the rest of the crew, instead they converted a corner of their shop into a breakroom.

I had one bloke tell me into my face when I asked him about a system, that as a lowly mechanic I wouldn't understand it anyway. Arsehole.

Jan
Je Suis Charlie et je suis Ahmet aussi
 
Tod
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RE: How Are Planes Tested After Maintenance Checks?

Wed Aug 24, 2005 11:29 pm

Quoting MD11Engineer (Reply 15):
as a lowly mechanic I wouldn't understand

Ouch!

That sounds like something one of us engineers might say. duck 

Tod wink 
 
VC-10
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RE: How Are Planes Tested After Maintenance Checks?

Thu Aug 25, 2005 12:14 am

Can we stay on topic please, otherwise I'll have to hit that delete button
 
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HAWK21M
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RE: How Are Planes Tested After Maintenance Checks?

Thu Aug 25, 2005 2:07 am

Wouldn't it be more reliable to carry out a Test Flight If the Rectification done cannot be simulated on Ground.

regds
MEL
I may not win often, but I damn well never lose!!! ;)
 
MD11Engineer
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RE: How Are Planes Tested After Maintenance Checks?

Thu Aug 25, 2005 6:15 am

Quoting VC-10 (Reply 17):
Can we stay on topic please, otherwise I'll have to hit that delete button

Are you avionics? Big grin

Jan  duck 
Je Suis Charlie et je suis Ahmet aussi

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