B737 Pressurisation
Thread Starter
Joined: Mar 2013
Posts: 177
Likes: 0
From: 36,000'
B737 Pressurisation
As per the FCOM
Any examples... Can some one please explain.
In certain circumstances the selected LAND ALT may exceed the target cabin altitude determined by the differential pressure limits. In these cases, the controller will maintain a cabin altitude slightly below the selected LAND ALT.
Last edited by B737NG_Pilot; 5th April 2022 at 12:24.
Joined: Jan 2008
Posts: 1,269
Likes: 79
From: Denver
Lacking additional context, I would think this has to do with the fact that there are an increasing number of medium-jet-capable commercial airports at elevations higher than what are usually considered "safe" cabin altitudes.
e.g. Daocheng Yading Intl, at 14000+ feet elevation.
https://www.airport-technology.com/f...-in-the-world/
If the system is designed to always maintain a max. cabin altitude of, say, 7500-10000 feet, that will be a issue. A minor one - the aircraft can be "depressurized" on landing - but not something designed into the normal limits of the sensors and gauges.
I believe that there are some aircraft with modified systems for such airports, but a "bog-standard" 737 or similar jet may need to go to one, and the FCOM item is just a reminder of the unusual situation.
e.g. Daocheng Yading Intl, at 14000+ feet elevation.
https://www.airport-technology.com/f...-in-the-world/
If the system is designed to always maintain a max. cabin altitude of, say, 7500-10000 feet, that will be a issue. A minor one - the aircraft can be "depressurized" on landing - but not something designed into the normal limits of the sensors and gauges.
I believe that there are some aircraft with modified systems for such airports, but a "bog-standard" 737 or similar jet may need to go to one, and the FCOM item is just a reminder of the unusual situation.
