737 cabin altitude question
 

A question for all you 737 jocks:
Since the 737 differential pressure schedule is lower than other Boeing planes (probably due to the fact that this model was designed for multiple cycles), cabin altitude tends to be on the high side (around 8K feet when you cruise at 37,000 or higher). Do you get any complaints from cabin or flight deck crews related to the high cabin altitude (especially on flights of 4+ hours)? Does your airline limit cruise levels due to possible risk to pax and effect of low O2 levels on flight deck performance?

On the -900ER its around 7500ft but then again its a brand new plane...I havent heard of anyone limiting cruise time due to cabin altitude so my answer is no but will stand corrected.

No limit, no complains so far, up to 8000ft is not really a problem after all.

There is a mod for the pressurization system available which limits the max cabin altitude to 6000ft and allows a higher differential pressure. However it requires additional maintenance later on and is probably not something many airlines will order, might be standard on the BBJ though.

Hi amos747,

We used to dream of having a cabin Altitude of only 8,000 ft in the old days!
Luxury. Pure luxury with only 8,000 ft.
Trouble is - when you tell the kids of today, they don't believe you.

viscount | starboard side | dart | 1957 | 1588 | Flight Archive

Neither of the recent military variants of the 737NG have any mods to the pressurization system as mentioned above, and they are very likely to be staying aloft for some very long flight times, quite regularly!
It's 8400 feet for most of the trips, the auxiliary fuel system depends on that cabin pressure, as it's regulated from the standard NG differential.
And for the same reason, you won't see any one of them dumping fuel below around FL200 either!
Cheers....:)