Is the 737 the only plane that you have to manually put in your cruise altitude on the cabin pressure panel?

I don't see it on the 747 or 767. Why is this a manual process? I sometimes forget to do this and it's left at 10,000 (when flying at FL200) - bad pilot Pauly!

But shouldn't this be an automated process?

It's standard procedure on the 737. Unfortunately, I don't know about the other planes.

Is the 737 the only plane that you have to manually put in your cruise altitude on the cabin pressure panel?

 

The 737 is the only aircraft in Boeing's fleet (modern; I don't know about the 707/727/classic 747). It is purely automatic (with a manual setting if needed).

 

Why is this a manual process?

 

I think it may have to do with Boeing keeping a lot of things in the NG similar as a homage to the early 737s.

I sometimes forget to do this and it's left at 10,000 (when flying at FL200)

 

Remember your checklists! Unless you want the virtual FAA (or other regulatory body).

 

But shouldn't this be an automated process?

 

Unless you are a pilot that does not adhere to the checklists, says the required response to the challenge or reumes the checklist in the wrong spot instead of restarting the checklist, it doesn't have to be automatic.

OK, then 1 follow up question.

 

Say you're at FL300 and you set the panel to 30,000. Now you are cleared to descend to 10,000 and you find you are remaining there (10,000 ft) for some time - do you adjust the altitude to 10,000 then?

do you adjust the altitude to 10,000 then?

 

I think SOP is to set it during preflight and don't touch it unless there is a step climb or the QRH calls for it to be set.

Say you're at FL300 and you set the panel to 30,000. Now you are cleared to descend to 10,000 and you find you are remaining there (10,000 ft) for some time - do you adjust the altitude to 10,000 then?

 

No need to change it. If you do though, no harm done but not a standard Boeing procedure.

When you started your descent from FL300, the automatic pressure controller programs a proportional descent to slightly below the selected LAND ALT. If you stop the descent at 10,000 feet for a while, the proportional decent stops where its at and starts again when you continue the descent.

The controller is fully automatic, the controller needs only to know the altitude you want to climb, on other plane it will take from fms CRZ altitude for example or MCP.

What changes in an incorrect setting is how the plane pressurize, the pressurization cycle is fully scheduled by the controller by giving that altitude, if you fail in giving the right one the airplane will still pressurize, but, in the wrong manner (and maybe uncomfortable for passengers) if you set an higher crz altitude and you descend BEFORE it, OFF SCHED descend will turn on, meaning that he already scheduled a different pressurization cycle, in any case, it will follow your descent and is ready to do the descent part of the flight.

If you set a lower altitude, it will pressurize for that altitude, then, if you are still climbing it try to mantain the pressurization until maximum limits (maximum differential pressure) are reached, when this happen, the outflow valve will open to unpressurize the plane at the same vertical speed of the aircraft.