cabin rate of climb with both packs off

[Microburst2002]

Is there any airworthiness requirement of having a maximum rate of climb of the cabin in case of losing both packs at cruising level?

I remember that this test was done in an airplane that my airline was giving back to the lessor, among others, years ago. However I don't know if the result of such test could render an airplane not airworthy.

[Flutter speed]

I recently had a discussion with a senior acceptance pilot from a mainline carrier and he told me that one of the acceptance tests was disabling both packs at cruise alt (max differential pressure). The resulting cabin ROC should not exceed 2000 fpm. I will try to substantiate it with a doc.

--from Boeing 737NG production flight test procedures:
http://i48.tinypic.com/34qmgyd.jpg

So apparently this is for new aircraft from the factory and its not a regulation source. But just FYI.

[Yeelep]

I remember that this test was done in an airplane that my airline was giving back to the lessor, among others, years ago. However I don't know if the result of such test could render an airplane not airworthy.

If it failed the test, the airworthiness of the aircraft would be suspended until it was fixed or possibly deferred using an engineering authorization(doubtful).

There is a airplane leak down check procedure on the 737NG as part of a single pack operational confidence check. Basically; pressurize to 4.2PSIG turn off packs, start timer at 4.0PSIG, stop timer at 2.5PSIG. If it takes less than 100 seconds maintenance is required. Ideal is between 120-130 seconds.

[4dogs]

Yeelep,

There is a big difference between a post-production/acceptance test schedule and airworthiness requirements. I have conducted a few of these that include certain items that "should work this way" but are a by-product of certification requirements rather than primary compliance items. Some of those items have been treated as 'show-stoppers' and others have been accepted as contractual alleviations - each decision has been commercial rather than regulatory.

When you say:

If it failed the test, the airworthiness of the aircraft would be suspended...

I presume that you have a specific certification requirement in mind?

Stay Alive,

[error_401]

I've done an acceptance flight with the flight test crew a 50 seater turboprop once.

Flight test engineer said. No specific limit but they accept up to 750 fpm climb at max diff pressure, else it goes back to check where it leaks for aircraft out of the factory - new or used.

Had a turboprop in Cargo outfit doing 2'500 fpm becaus of a missing seal and a misaligned door.

[Microburst2002]

So it is pretty much as looking at the teeth of a horse before buying it...

[Yeelep]

4dogs,

If I read your post correctly, the lessor's requirements may be more restrictive than the requirements for continued airworthiness. If so, that's a good point and one that I hadn't thought of. :O