smartt1982
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ETOPS, Still Air And The APU?

Sat Feb 09, 2013 2:54 pm

With regards to ETOPS, what I’ve read talks about still air conditions.

Would I be right in thinking that this time can go up or down depending on what headwind/tailwind conditions you have on the day?

Is it ever a requirement to have the APU running for the entire ETOPS segment at all?
 
Mender
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RE: ETOPS, Still Air And The APU?

Sat Feb 09, 2013 3:05 pm

You can't really make a clear and simple rule is you allow for variables such as wind speed and direction therefore the clearest and simplest definition is to define the time limit for flying in still air conditions.

You can usually depart with an electrical generator U/S if you have the APU running throughout the flight.
 
Tristarsteve
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RE: ETOPS, Still Air And The APU?

Sat Feb 09, 2013 4:16 pm

Quoting smartt1982 (Thread starter):
Is it ever a requirement to have the APU running for the entire ETOPS segment at all?

The answer is that it depends on the aircraft.
Some aircraft like B777 have enough generators, and a RAT, and can be dispatched with the APU inop.
Some aircraft like B737 have only 2 generators and no RAT and APU must be running.
Some aircraft like A320 have 2 generators and a RAT and the APU must be serviceable but not running.
And these requirements can change for 120mins and 180mins ETOPS.
 
yeelep
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RE: ETOPS, Still Air And The APU?

Sat Feb 09, 2013 5:06 pm

Quoting Tristarsteve (Reply 2):
Some aircraft like B737 have only 2 generators and no RAT and APU must be running.

As with almost everything, there are exceptions. On the 737NG, on a per airline basis, the FAA allows for the APU to not be running during ETOPS if certain maintenance, operational and reliability criteria are met.
 
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HAWK21M
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RE: ETOPS, Still Air And The APU?

Sat Feb 09, 2013 6:51 pm

Quoting yeelep (Reply 3):
On the 737NG, on a per airline basis, the FAA allows for the APU to not be running during ETOPS if certain maintenance, operational and reliability criteria are met.

Pls elaborate......Im sure you meant serviceable but not operational APU at that moment.
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yeelep
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RE: ETOPS, Still Air And The APU?

Sun Feb 10, 2013 3:28 am

There is an operational requirement to cold soak start the APU at cruise altitude. It has to be performed each 30 to 90 days to maintain the APU on Demand status of the plane.
 
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HAWK21M
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RE: ETOPS, Still Air And The APU?

Sat Feb 16, 2013 10:15 am

Quoting yeelep (Reply 5):
There is an operational requirement to cold soak start the APU at cruise altitude. It has to be performed each 30 to 90 days to maintain the APU on Demand status of the plane.

Isn't the duration of test a bit too long.....was Wondering.
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Fabo
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RE: ETOPS, Still Air And The APU?

Mon Feb 18, 2013 2:30 pm

Since it is not a safety critical thing (no APU before entering ETOPS airspace? Turn around to first alternate, less than 60min away), I guess it is acceptable. I would probably like to test it a bit more often though.
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yeelep
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RE: ETOPS, Still Air And The APU?

Mon Feb 18, 2013 9:08 pm

Quoting HAWK21M (Reply 6):
Isn't the duration of test a bit too long.....was Wondering.

Its a limit set by the FAA, you would have to ask them. However, I had poorly written the requirement. The check has to be performed within 30 days from the previous check. This can be extended to 60 days or 90 days based on the airlines historical data of these checks and with FAA approval. I don't know what the criteria is to allow the extension.

There are other things that also have to be done to allow APU on Demand, such as a EGT monitoring program/limits, component requirements and a modified maintenance program.

Quoting Fabo (Reply 7):
(no APU before entering ETOPS airspace? Turn around to first alternate, less than 60min away)

With APU on Demand, at no time during the flight including the ETOPS portion, does the APU need to be running.

[Edited 2013-02-18 13:21:02]
 
Fabo
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RE: ETOPS, Still Air And The APU?

Tue Feb 19, 2013 10:50 am

Quoting yeelep (Reply 8):
With APU on Demand, at no time during the flight including the ETOPS portion, does the APU need to be running.

Ah, yes. Used to the procedure I had on the NG, APU needed to run in ETOPS airspace.
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yeelep
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RE: ETOPS, Still Air And The APU?

Tue Feb 19, 2013 5:23 pm

As its a FAA approved program, only US based Airlines that fly 737NG's to Hawaii can benefit.
 
flybaurlax
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RE: ETOPS, Still Air And The APU?

Wed Feb 20, 2013 6:36 pm

Quoting yeelep (Reply 8):
Its a limit set by the FAA, you would have to ask them. However, I had poorly written the requirement. The check has to be performed within 30 days from the previous check. This can be extended to 60 days or 90 days based on the airlines historical data of these checks and with FAA approval. I don't know what the criteria is to allow the extension.

There are other things that also have to be done to allow APU on Demand, such as a EGT monitoring program/limits, component requirements and a modified maintenance program.

The CMP requires 30 days, but can be extended to 120 days. The criteria required to allow the extension is proven reliability of the program, including the 95% start success rate.

Quoting yeelep (Reply 10):
As its a FAA approved program, only US based Airlines that fly 737NG's to Hawaii can benefit.

Other governing agencies follow the FAA requirements, so non US carriers would also benefit. There are currently 2 US operators using APUOD, and another operator across the pond is seeking the program.
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