Emergency declaration one power supply

[sultangc]

Hello everybody, my first time here. I would like to know if you are flying with an engine generator out of service and deferred, by maintenance, and one engine generator and APU generator only, and one of this remaining generator fail , so from now flying with only ONE generator, one power suply we must declare emergency to the ATC control?? Thanks

[M.82]

B737NG

Ground = MEL
ENGINE DRIVE GENERATOR SYSTEM = Number installed 2
Number required for dispatch 1
Except for ER operations, may be inoperative provided APU generator operates normally and is used throughout flight.

Air = QRH
DRIVE

(with APU not avalable for start)
"2- Plan to land at the nearest suitable airport
ONLY ONE MAIN AC POWER REMAINS"


Yes, with only one source of power, I will make a mayday call for shure.
My opinion.

[Agaricus bisporus]

It rather depends on what you're flying and what the company policy is. An aeroplane with 2 engines and an APU is going to be attached to a MEL and Ops manual that will answer that question, surely?

[Notso Fantastic]

I have a suspicion that M.82 is yet another pretend home simulator pilot- the trouble is they are spinning out advice here now!

Beware of advice from anonymous sources like this. A proper definition of Mayday is 'aircraft is in grave and imminent danger'. Ending up on one power source is NOT a grave and imminent danger! 'Land at nearest suitable airport' is an alert- a Pan-Pan call is more appropriate. If you lose your last source, you still have a minimum of 30 minutes battery power.

[M.82]

Yes sure, like the one from above said, a PAN PAN would be better.
But the 737 NG that i fly has 60min battery power, Sooo sory

[Denti]

Depends i guess. Boeing defines ER operation as ETOPS 120 or more on the 737, therefore you may be up to 90 minutes away from a suitable airport when your second power source fails, another failure would mean 30 minutes without any electric power until reaching your suitable enroute alternate. Hope you have your handheld GPS ready.

[BOAC]

Sultangc - you declare the level of emergency you need in this case - there is no 'fixed rule'. If you try a PAN and no-one understands, then you call Mayday. If ATC and everything are going along nicely taking you to a nearby diversion airfield, you may elect to delay declaring such. Not a bad idea though at some point to focus minds.

This 30/60 thing is confusing everyone unnecessarily - it is a customer option unless a standard fit on later models. Flying for 90 minutes on a 60 minute battery is just as it always was, Denti. Switch off the electrics until you need them again. Assuming you would not dispatch?? with less than 3 electrical sources on ER you are building up a very bad day to lose three at the same time, and something that is not planned for. Why not short out the batteries as well and have a really good day?

[deltahotel]

From my QRH "declare an emergency and plan to land at the nearest suitable airport".

[sultangc]

It mainly in fly so the MEL could be an source of information but in this case surely is NO GO or NO DISPACH. And in the order hand OPS Manual of mi company, do not say nothing about that. A May day some an extreme an a PAN PAN so soft or light for me. Waiting to fall down in a Total Emergengy, from here is a MAY DAY surely doesn't matter is a have 30, 45 or 60 min of battery, o not?
Thank you very much for your point of view.

[sultangc]

thank DH. That the reason of my question in my QRH don't mention anything about MAY DAY only land ASAP.

[sultangc]

Thank you I agree with you mostly.