Power down 737 buzzer/sound
Thread Starter
Joined: Sep 2002
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From: The Netherlands
Power down 737 buzzer/sound
Hi there,
when you power down the 737, just before you turn off the battery, the 737 gives a distinct sound.
Is it harmfull to turn off the battery while this sound is still on or has Boeing a special purpose with this sound?
I have been told that if you turn off the battery while the sound is still on , the next crew might have a failure/alert upon powering up, because some sort of internal check has not been completed.
Anybody any comment on this.
Thanks
when you power down the 737, just before you turn off the battery, the 737 gives a distinct sound.
Is it harmfull to turn off the battery while this sound is still on or has Boeing a special purpose with this sound?
I have been told that if you turn off the battery while the sound is still on , the next crew might have a failure/alert upon powering up, because some sort of internal check has not been completed.
Anybody any comment on this.
Thanks
Joined: Apr 2012
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From: In Space
That sound is usually the gyro in the standby instruments spooling down, so its ok to turn it all off.
If the aircraft is on Battery power alone the sound could be the IRS horn in the Nose wheel bay, stating the IRS are powered by DC power only.
For the latter, the IRS would have to be on still. My guess is the first suggestion and its the gyros spoiling down.
If the aircraft is on Battery power alone the sound could be the IRS horn in the Nose wheel bay, stating the IRS are powered by DC power only.
For the latter, the IRS would have to be on still. My guess is the first suggestion and its the gyros spoiling down.
Joined: Jun 2000
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From: last time I looked I was still here.
If no external AC source the buzzer is the BAT discharge warning. It is associated with the R IRS on DC, but it is BAT discharge. On the ground, the R IRS on DC is not too important. The BAT discharge is significant, as when you come out in the morning and try to crank the APU. Whoops!
Joined: Nov 2010
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From: Europe
I don't think it's the IRS horn the question is about since if it's a power down we are talking about, you probably turned off the IRS anyway. The sound is when you for example turn off the ground power, a second later it comes a sound that last for a second and then you turn off the battery.
Joined: Aug 2008
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From: Betwixt and between
There is no noise on our NGs during the Electrical Power Down regardless if the battery is discharging. Try setting the STANDBY POWER switch to OFF on the ground prior to the secure procedure, this isolates the standby system and causes a battery discharge with no alarm. The noise on our NGs is only present if the IRS is on.
Gender Faculty Specialist
Joined: Mar 2002
Aviation Qualifications: ATPL
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From: In your head.
There is actually another aural warning that hasn't been mentioned. It starts after a specific time on battery power and it's NOT the IRS warning. I recently learnt about it in our annual tech. exam but I cannot for the life of me remember anything more specific.
I'll see if I can dig it up.
I'll see if I can dig it up.
Joined: Oct 2006
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From: Ankh Morpork, DW
Why? Why can't you just hit the ground service switch on the way out the door?
Joined: Apr 2012
Posts: 50
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From: Australia
Otto Throttle,
I'm replying as a "plonker pilot". The company I work for has S.O.P's. You may be aware of these.
I have a great admiration and respect for our engineers, a fanatastic bunch of men and women, who, also understand S.O.P's.
When our procedures call for the de-powering of the aeroplane, we do so. The before said engineers, who understand our procedures, when required, ask if we could not do so on this occasion so as to facilitate certain other requirements...
I'm replying as a "plonker pilot". The company I work for has S.O.P's. You may be aware of these.
I have a great admiration and respect for our engineers, a fanatastic bunch of men and women, who, also understand S.O.P's.
When our procedures call for the de-powering of the aeroplane, we do so. The before said engineers, who understand our procedures, when required, ask if we could not do so on this occasion so as to facilitate certain other requirements...
