I have a few questions on how to operate a realistic 737 NG ETOPS flight.1. I read somewhere that the crew has to keep the APU on throughout the cruise (because the 737 has no RAT) - is this true? Or is it only turned on/off periodically through the cruise?2. Is there some special minimum landing fuel requirement?3. Say I am flying SEA-OGG and I want to do a step-climb to FL360 to save fuel. If this is allowed, would I request it on my next position report to San Franscisco radio or whenever I want?I did alot of crossings with the 757/767 on VATSIM but now that I can finally do the ASA routes in the NGX, I want to do them as realistically as possible Ethan

1. Simply put no. Most airlines i heard(could be wrong) try to keep the apu on for a little as possible to get running time down and save fuel.2. The general rule is for enough fuel to an alternative and 45 extra minutes of flight.

regarding number 1, everything I have read and heard about ETOPS on the NG, the APU is turned on for engine start, and left on for take off and into cruise. You cannot start the APU at cruise altitude, at least not with any sort of consistancy, so where Dmitriy got his idea from I don't know, but from what I have understood about the NG, turn the APU on for engine start, leave it on until you leave the ETOPS part of the flight, and you cannot enter the ETOPS portion of the flight without confirmation that the APU is running.

Oops your right. I missed the ETOPS part. Sorry That just shows me I need more sleep. So dont listen to me beacuse I will blapper out a wrong answer :) Good night

On an ETOPS flight, you start the APU before reaching the ETOPS Entry Point and is left on until passing the ETOPS Exit Point. The APU can be started inflight and thats how it's done on an ETOPS flight, you don't leave the APU running from before engine start to the ETOPS Exit Point because the ETOPS part of the flight might be an hour or two after departure.

On an ETOPS flight, you start the APU before reaching the ETOPS Entry Point and is left on until passing the ETOPS Exit Point. The APU can be started inflight and thats how it's done on an ETOPS flight, you don't leave the APU running from before engine start to the ETOPS Exit Point because the ETOPS part of the flight might be an hour or two after departure.

Since the APU has a maximum altitude at which it can be started reliably, isn't it typically more cost efficient to leave it on than to risk descending to start it & then climb back up to cruise?

Since the APU has a maximum altitude at which it can be started reliably, isn't it typically more cost efficient to leave it on than to risk descending to start it & then climb back up to cruise?

I believe that's what Jack Colwill said in a post before when his company does it. Start it, and don't shut it off, because of that, untill past the ETOPS. Course they do Vancouver to Hawaii, so it's probably only 30-45 minutes before the ETOPS portion starts (I think going off the top of my head).

I have a few questions on how to operate a realistic 737 NG ETOPS flight.1. I read somewhere that the crew has to keep the APU on throughout the cruise (because the 737 has no RAT) - is this true? Or is it only turned on/off periodically through the cruise?2. Is there some special minimum landing fuel requirement?3. Say I am flying SEA-OGG and I want to do a step-climb to FL360 to save fuel. If this is allowed, would I request it on my next position report to San Franscisco radio or whenever I want?I did alot of crossings with the 757/767 on VATSIM but now that I can finally do the ASA routes in the NGX, I want to do them as realistically as possible Ethan

If you want to do the Alaska procedures, leave the APU running from pushback to the EXP.The fuel load is fairly involved. It's not a simple 45 minutes. You have to take into consideration engine failure and decompression and 5% wind additive and, well, you get the picture.You can request the step climb from SFO whenever you want to. You'll be doing it on HF if you're simulating the Alaska livery and sometimes that takes a while.I think one of the posters on here actually does AS fuel planning for the ETOPS flights. He might be able to go more into that realm.

Spin has it right, AS SOP is to keep the APU running from engine start to EXP. Now, Alaska is currently working for FAA approval for what's called APUOD or the APU On Demand program. Once approved, Alaska will no longer be required to run the APU while operating in the ETOPS Operation Area. Basically for the past few months Alaska has been testing what's called cold soaked starts of the APU during flights 5+ hours long during non-ETOPS Flights (SEA-BOS or SEA-MIA) to test and prove that the APU can be started and loaded after 3 or more hours at cruise. Once the APU On Demand ETOPS approval is given, ill post a quick NOTAM for the AS ETOPSOperation NGX pilots out there.

I just did the HNL-ANC ETOPS flight....thats a long way from anything.

In the 737NG FCOM, it states that you can operate and start the APU up to the airplane maximum certified altitude.I know the descent to start the APU is there to make sure it can suck in sufficient (and sufficiently thick) air to start. But according to the FCOM, this descent is not needed.I imagine the only reason the descent is carried out, is to reduce wear and tear on the APU?

These was an A330 flight not long ago where they did a descent to start the engine and then climbed back to cruise. http://avherald.com/h?article=43e611bf&opt=0That's not required on the NG. If you were down to only standby power, I think I'd wait a bit to start the APU at a lower altitude, just as added insurance.

Thanks for the responses everyone@599AS - definitely tell me when that happens, sounds interesting!

Per FCOM, "The APU starts and operates up to the airplane maximum certified altitude", so there is no problem starting the APU in flight--no need to leave APU running from pushback.A major US-based NG operator's FCOM says to run APU when flying ETOPS segment. Also, to operate the fuel crossfeed valve in the last hour of ETOPS to ensure that crossfeed works for the next ETOPS flight.This is for APU as electrical backup only. For APU bleed operation it's 17000 ft max, and for APU bleed + electrical use it's 10000 ft.The above technical limitations aside, your airline's FCOM may differ and may have further restrictions!

Per FCOM, "The APU starts and operates up to the airplane maximum certified altitude", so there is no problem starting the APU in flight--no need to leave APU running from pushback.A major US-based NG operator's FCOM says to run APU when flying ETOPS segment. Also, to operate the fuel crossfeed valve in the last hour of ETOPS to ensure that crossfeed works for the next ETOPS flight.This is for APU as electrical backup only. For APU bleed operation it's 17000 ft max, and for APU bleed + electrical use it's 10000 ft.The above technical limitations aside, your airline's FCOM may differ and may have further restrictions!

Most airlines doing ETOPS leave the APU running until the ETOPS Exit point. It is cheaper to run it than to abort a crossing because they couldn't get it started. FWIW.