On modern airliners, what flight deck instruments are available in the case of loss of all electric power?

convair880mfan · Thu Sep 30, 2021 6:06 pm

I have heard that all airlines have a wet compass [viewed by a mirror, I believe, on the MD-80 series aircraft]. What other instruments will continue to function in the case of a loss of all electric power [exceedingly rare I guess because of RATs]?. Could airline pilots use their cell phones or laptops to get GPS or communicate with ATC? Info of the Internet is kind of sketchy on this subject.

JustAnFO · Thu Sep 30, 2021 6:09 pm

convair880mfan wrote:
I have heard that all airlines have a wet compass [viewed by a mirror, I believe, on the MD-80 series aircraft]. What other instruments will continue to function in the case of a loss of all electric power [exceedingly rare I guess because of RATs]?. Could airline pilots use their cell phones or laptops to get GPS or communicate with ATC? Info of the Internet is kind of sketchy on this subject.

The emergency electrical system powers one VHF comm radio for ATC communications, and one ILS receiver.
Mobile phones generally don’t work from a plane above a couple thousand feet AGL or over water or sparsely populated areas, so that technique isn’t even considered. (Though it has been known to be used by more than one pilot in distress.) A stand-alone GPS nav system like a handheld GPS or an EFB/iPad are not certified as part of any emergency-powered aircraft system that I know of, but a resourceful pilot would certainly use them if available.

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Starlionblue · Fri Oct 01, 2021 12:06 am

convair880mfan wrote:
I have heard that all airlines have a wet compass [viewed by a mirror, I believe, on the MD-80 series aircraft]. What other instruments will continue to function in the case of a loss of all electric power [exceedingly rare I guess because of RATs]?. Could airline pilots use their cell phones or laptops to get GPS or communicate with ATC? Info of the Internet is kind of sketchy on this subject.

If we lose all electric power on the A330 or A350, the aircraft is not controllable. That's why we have a RAT. The A330 can be flown on batteries only, but that's really just a temporary measure until the emergency generator kicks in and/or the APU is started. AFAIK, flight on batteries only is not catered for on the A350, because the RAT drives an electrical generator directly.

In the case of emergency electrical configuration on the A330 (all main generators lost), you retain Captain's PFD, the upper centre display, the left dome light, one set of radios, one GPS, one autopilot, one set of pitot and AoA probes heated. And yes, the compass. Flight controls degrade to Alternate Law.