251 Grounded

[BoeingBoy]

When pushing back from the gate, you're right. "On the ground" encompasses a lot more than merely pushing back from the gate.

On the general subject, the pack(s) are activated shortly after engine start, so air is being pumped into the cabin. Even with the outflow valve open there would be some resistance to outside air entering the cabin through a faulty door seal. That's why it's much more likely, if the odor was engine exhaust, that the engine(s) were sucking in the air and pumping it into the cabin via the pack(s).

Jim

 

[700UW]

When US first got the F100s they didnt realize you couldnt hook up the ground air without the outflow valve being opened. One night I was working third shift and I was assigned a F100 on A6 the ground air was hooked up, I went to open the door and it threw me back and dust went flying everywhere and the door knocked me down.

 

[BoeingBoy]

I went to open the door and it threw me back and dust went flying everywhere and the door knocked me down.

See, you can open a door with the plane pressurized...

Jim

 

[Dog Wonder]

See, you can open a door with the plane pressurized...

Jim

The same thing can happen on an Airbus if you don't wait for the signal from the FA.

 

[BoeingBoy]

Generally there's so little differential pressure on the ground that it's possible to open a door - a little harder than unpressurized but possible.

Jim

 

[usabusdriver]

Generally there's so little differential pressure on the ground that it's possible to open a door - a little harder than unpressurized but possible.

Jim

Jim is correct about the packs. They produce a quite substantial airflow that would make migration of fumes / odors from outside to inside from faulty door seals virtually impossible.

Ponder this question. What is the gap that would be theoretically possible from a faulty door seal? Compare that to the dimensions of the outflow valve. The outflow valve is ALWAYS open on the ground, yet no complaints about fumes / odors.



.

 

[BoeingBoy]

The outflow valve is ALWAYS open on the ground

Just a question since I didn't fly the 767 - do you not pressurize to 1/8th psi for takeoff and landing like the 72's and 73's?

Jim

 

[phasersonstun2]

Just a question since I didn't fly the 767 - do you not pressurize to 1/8th psi for takeoff and landing like the 72's and 73's?

Jim

Correct. Pressurized to .125

 

[comatose]

So, the FAA finds two bad rear door seals. Did they happen to ask why there were 7 crew members in the aft galley. What a joke. I have yet to meet a qualified inspector.