737NG thrust mode display

[poschrob]

Hi all,

first, please note that I am not a pilot, just an enthausiast looking for some detailed information I couldn't find anywhere else.

Having checked several NG cockpit pictures (aircraft parked with the engines shut down) I've realized that on most of them the Eninge Thrust Display is showing three dashes (---) as default. A specific airline's FCOM mentions that crews must check this condition as part of the flightdeck preparation.

The question would be whether this is the default condition or a software related thing - as on some other aircraft the thrust setting is displayed (e.g. TO), not the dashes.

Thanks in advance!

Robert

[Johnny Tightlips]

My FCOM for the -800 says:

– – – – when N1 SET outer knob is in AUTO position and FMC source
invalid.

If the aircraft is shut down all the inputs in the FMC are reset for the next flight and if the outside air temp(OAT) is not entered, the FMC can not calculate the N1 and so you would see the dashes. This is my best expiation for it but others might have a different idea. We as pilots don't really notice things like this because once we set everything up properly and do the checklist all these little things should have sorted themselves out and we never see them.

[poschrob]

Thanks a bunch, all I wanted to know!

[SlowAndSilly]

Me thinks... (at least on the CL) That if you pay for the aspired temp probe you will have digits/mode on the ground since correct temperature is sensed also on ground?

[poschrob]

@ SlowAndSilly,

your statement seems to be correct, as the below excerpt from a slightly older FMC guide confirms it

"BOX prompts: Enter actual OAT for takeoff N1 calculations except if the airplane has aspirated TAT probe, in which case OAT from the probe is displayed"