Originally Posted by
TaylorPilot26
Good question for retirees watching how procedures evolve. The core principle hasn't changed — immediate descent takes priority over ATC coordination — but how that interplays with modern airspace has been refined a bit.
Not really true. Communication is extremely important as it takes time but at least everybody is aware what is going to happen (a rapid descent). On a Boeing, the PF would advice the cabin, the PM would advice ATC. Only then the "without delay descend..." step is handled.
You give ATC a chance to vector other traffic away from you. However, as correctly mentioned before: terrain is factor as well, so you need a regional QNH from ATC. If you don't have that QNH, you can't completely rely on your charted terrain altitudes because you are probably flying flight levels. Even thought there might only be 500ft difference, it should be on your mind as a pilot when you are preparing an intermediate level off in high terrain.