B737 Stby Pwr Off At The Gate
 

One of our airplanes a few days ago had the Standby Power Off light illuminated at the gate next to ours, and despite various attempts to reset the whole airplane, the crew was unable to get rid of it and the flight had to be cancelled.



Anybody experienced this before? Any valuable trick in mind?


(sorry about wrong title, it's 737 of course, not 373, but can't edit it now...)

LEM was that the Standby Power Off light or the f****ing Standby Power Off light? Very important to distinguish!

sorry I am unable to offer any real insight mate

rgds,
GP.

@ LEM
Do you know any further Information of the Indication on AC Voltmeter and Frequency Meter at different
Standby Power Switch Positions?

Ingo

Did they check that the Standby Power Off light was not stuck in(bulb test position)?

Sounds a bit of an obvious one, but I have watch two crew members tell the engineer to give the cargo door another stut over and over again. when all that was required was a quick flick of the bulb to make it spring out from its test position.

IFixPlanes, I've got no info on that, thanks anyway.

Touch'n'oops, yes it's true sometimes the most obviuous ideas don't come to mind, so it's certainly a good idea to think about that - the bulb stuck in the test position. :ok:

Hi all,

My understanding is that there is no 'test' position for that annunciator, its tested along with all the others, with the lights test switch on the P1 panel!

Also, if the Standby Power switch is selected to OFF, the Standby Power OFF light will come on, its supposed to!

Also, the control module sometimes fails, with this result - used to happen in the '74 sometimes!

We always selected the Standby Power switch OFF after every flight, can cause a problem otherwise!

FD

:uhoh:

@ FD
In a 737 you can test almost every annunciator by pressing him in. It is not the usual way but possible.

Ingo

Hi Flight Detent,
Intetersting, never heard about that before.

Could you elaborate that for me?
Thanks! LEM

I checked up on whether it is possible to test the 'Standby power off' bulb by pressing... It worked a treat, then stuck-in!!!:=
A quick flick and it was out!!!

Remember a lot of people bash their heads on the overhead panel creating all sorts of chaos!!! Not quite, but the point is there!!!!:rolleyes:

Hi LEM,

OK, anytime the battery is switched ON, without AC power applied to the airplane, both the main and auxiliary batteries will power the standby power system.

Consider, if the external ground aircon was connected to the airplane, the battery is required to be on to power the protective dc circuits; anytime the APU is started the battery needs to be on; if both battery and external power are on, and the external power has some sort if hiccup, as it occasionally does, standby power will come on.

When standby power comes on, it powers all of the Captns side navigation/approach/communication systems (and his clock), and is good for an hour at a stretch!

Selecting the Standby Power switch to OFF, in the secure checklist will alleviate all these possibilities, and both batteries will most probably be fully charged when you arrive to fly that night flight.
Our normal procedures also has the Captn selecting standby power to auto during his cockpit prep, noting the OFF light goes out.

Cheers, FD:cool:

HI Flight Detent, now I'm puzzled!...

I thought the Standby buses couldn't be powered on the ground with the Standby Power switch to AUTO!

Or have I missed anything?

Hi LEM,

It sure can, it's not flt/grnd sensitive!

Cheers, FD

This is why it is so important to state WHICH 737 variant you are talking about!

NG can power the Standby bus in Auto on the ground

Classic not, inhibited by air/ground sensor (although my fading memory tells me that some Classic variants would? It may have been some of the 'weird' 500's we had in BA but I cannot recall)

All clear now, thanks!