Originally Posted by
gearpins
is the ceiling is limited due to the factors related to press,like delta p,max cab alt,time taken for emergency descend..or thrust related?
Be careful with terminology. The aircraft are cleared to an altitude, therefore their certified maximum altitude is as stated, and this is presented as a "Limitation" in the Aircraft Flight Manual, Pilot Manual, or equivalent.
This need not be a true 'limit' on the aircraft's capabilities; it's possible that there is no hard boundary at FL510, simply that the OEM has not pushed the certification beyond that point. While an optimised design shouldn't have much margin left at the edges of the envelope, you can't necessarily reverse engineer the actual capability of an aircraft from any published limitations. Everyone likes to keep a little something in their back pocket, and there's no way to be sure exactly how full that pocket is.