Thanks Kristian,
My question was as the title says "setting FLT ALT lower than actual", the incident itself was just to give some info why I raised the question, and have no relevance. We followed the QRH accordingly.
Window crack or not, what happens if you select a FLT ALT lower than the actual FL in AUTO mode.
I agree that you should not try to invent the wheel again, but I now understand more what he was trying to do.
This was not the question but If you really need to reduce the differential pressure, our QRH says:
14 CAB ALT indicator . . . . . . . . . . . . . . . .9,000 feet
15 Pressurization mode selector . . . . . . . . . . . STBY
16 CABIN RATE selector. . . . . . . . . . . . . .As needed
17 Choose one:
Minimum safe altitude is below 14,000 feet:
>>Go to step 18
18 Descend to below 14,000 feet.
19 Maintain a cabin differential pressure of 2 psi or
less by limiting flight altitude to below 14,000 feet.
DO NOT USE FOR FLIGHT.
Thanks all for your inputs
