Inop APU

[NYARTCCFAN]

Can an aircraft namely a 757-300 be operated with an inop. APU and cleared for flight ?

[hiss srq]

It sure can. It simply put means they keep one turning till an air hose is hooked up for AC and a GPU for power is plugged in. When ready to depart they have to airstart one at the gate and than cross bleed the second one to start it once off the gate.

[RDU-JFK]

My Skywest flight from SBA to DEN had an inop APU. Made for a very hot boarding/taxi process!

[cancidas]

all aircraft can, they just rely on ground electric and air.

[NYARTCCFAN]

Tell me about it !!!!!!!!!!! No A/C at FLL waiting for T/O, then to make matters worse we spent 2 hours on ground at no gate at BWI waiting to refuel after diverting there due to Min Fuel declaration after holding.The F/A's were passing out free water yes free water and pretzels to butter us up befor being cleared to EWR. The pilot even said we didn't have to pay for the BWI-EWR leg of the trip. Boy was he funny saying that.

[LGA777]

Early jetliners like the 707 and DC-8 did not even have APU's. As a kid, prior to the opening of the current terminal at TPA in 1971, I spent many and afternoon on the observation deck of the old TPA terminal observation deck. The Gate right in front of the deck was the only gate that did not require the aircraft to pushback. they just taxied forward, so all 4 engines where started right on the gate, and the main aircraft to park their where National DC-8's, and Pan Am 707 & 720's. They had this old air start unit that sounded sort of like a loud siren as it started each engine, it was a wonderful experiance listening to all four turbofans come to life then scream as they powered off the gate, sometimes making a quick right turn and blasting all of us on the deck with jetblast and a heat bath, ah the memories, thanks Mom and Dad !

LGA777

[T-Bird76]

Recently I was on a Mesa CRJ-900 out of CLT and the APU wasn't working correctly. They fixed it by as the pilot put it "doing a CTRL-ALT-Delete" to the aircrafts PC. Two people got off because they felt uncomfortable but I got a laugh out of it.

[Informant]

Yes it can actually any aircraft can. However it cannot be cleared for ETOPS operations. In fact when maintenance does get around to fixing the APU, to regain the ETOPS certification the aircraft must perform a 2 hour cold soak test of the APU in flight at altitude, this can be done on a teste flight with no pax or on a normal revenue pax\cargo flight. The flight crew must start the APU and keep it on for 2 hours, and record it.

And some more info-beacuse I am the 'Informant'

Most 757/767 aircraft today have APU's than can take hot bleed air from the engines to warm up the oil, so that it thins from its honey-like state.

[PhilDernerJr]

For certain types, isn't is that you still have ETOPS, but just not for as long? Like an inop APU means you fly 120 ETOPS instead of 180?

[Informant]

From what I remember its all or nothing

[NYCMedic]

ETOPS is mostly about system redundancy, but in the case of the APU obviously there is only one. An Inop APU will negate your ETOPS status, that's why many airlines will delay their flights the approx 2hrs it takes to replace an APU rather than go non-ETOPS. In the case of an engine failure at altitude you are supposed to be able to cold start the APU at temps to around -40 degrees Celsius to act as the main generator and take stress off of the remaining engine.

[Informant]

that's why many airlines will delay their flights the approx 2hrs it takes to replace an APU rather than go non-ETOPS

You can replace an APU in about 45 minutes.

[cancidas]

that's why many airlines will delay their flights the approx 2hrs it takes to replace an APU rather than go non-ETOPS

You can replace an APU in about 45 minutes.

replace, yes. but don't forget you have to find the parts, replace them, refit all the panels, sign off the airplane, test it, most likely bring it back to a gate, board all the pax and load the cargo again too. usually, that takes longer than just 45 minutes, especially on say a 757 or 767. also, the majority of today's mx work is done with mx control close at hand by phone to assit in troubleshooting and such. talking on the phone takes time away too. oh yea, you also have to make sure that mx control and dispatch know the ship is fixed.