IAHFLYR
Topic Author
Posts: 3943
Joined: Sat Jun 25, 2005 12:56 am

AA Super 80 Gate Engine Shutdown Proc.

Wed Jan 24, 2007 6:28 am

I have a good opportunity to observe the Terminal A ramp at IAH where AA parks on the southside which creates the question of why do the Super 80's keep 1 engine running for 3-5 minutes once parked at the jetway, in the chocks, jetway connected, and baggage door open?

I've witnessed this numerous times and only find this to happen with AA and their 80's....CO didn't operate their MD80 fleet in such a manner when they flew them nor do I find the AA B738's doing it either, but that may only be due to the quieter engines on the B738.

Thanks in advance for all ideas and help.  

[Edited 2007-01-23 22:28:19]
Any views shared are strictly my own and do not a represent those of any former employer.
 
MX757
Posts: 495
Joined: Wed Aug 17, 2005 5:38 pm

RE: AA Super 80 Gate Engine Shutdown Proc.

Wed Jan 24, 2007 6:42 am

That's a very interesting observation. The only reason I can think why AA leaves an engine running is that the APU is inoperative and they are waiting for external power to be hooked up before shutting down the engine.

How many a/c did you observe?
Is it broke...? Yeah I'll fix it.
 
IAHFLYR
Topic Author
Posts: 3943
Joined: Sat Jun 25, 2005 12:56 am

RE: AA Super 80 Gate Engine Shutdown Proc.

Wed Jan 24, 2007 6:52 am

Quoting MX757 (Reply 1):
How many a/c did you observe?


Almost everyone of them......but I didn't think about the APU and it might be to save cycles on the APU and that little bit of fuel it would burn while they are connecting up the ground power! MMMM I don't think that is a likely senario as the extra fuel burned with the engine at idle would seem to be worth more than the APU cycles and fuel burn of the APU!  Confused
Any views shared are strictly my own and do not a represent those of any former employer.
 
VTBDflyer
Posts: 341
Joined: Thu Aug 10, 2006 12:04 pm

RE: AA Super 80 Gate Engine Shutdown Proc.

Wed Jan 24, 2007 8:16 am

Quoting IAHFLYR (Reply 2):
Almost everyone of them......but I didn't think about the APU and it might be to save cycles on the APU and that little bit of fuel it would burn while they are connecting up the ground power! MMMM I don't think that is a likely senario as the extra fuel burned with the engine at idle would seem to be worth more than the APU cycles and fuel burn of the APU!

It does take a little while for the APU to start up, so for a short period of time both the engines and APU are running. But, I'm not sure that it would make a huge difference in dollars lost.

VTBDflyer
Fly Thai
 
MX757
Posts: 495
Joined: Wed Aug 17, 2005 5:38 pm

RE: AA Super 80 Gate Engine Shutdown Proc.

Wed Jan 24, 2007 8:43 am

Quoting VTBDflyer (Reply 3):
It does take a little while for the APU to start up, so for a short period of time both the engines and APU are running. But, I'm not sure that it would make a huge difference in dollars lost.

This sounds like a very likely scenario. I agree with you, I don't think it would make a huge difference either. I guess AA crunched the numbers and decided it was cheaper to leave number 1 engine running instead of cranking the APU.
Is it broke...? Yeah I'll fix it.
 
AAR90
Posts: 3140
Joined: Fri Jan 21, 2000 11:51 am

RE: AA Super 80 Gate Engine Shutdown Proc.

Wed Jan 24, 2007 11:44 am

Way...way...way back when I was flying MD80s, AA published an 8 minute break even cost/benefit point for APU vs. one engine idle at the gate. At that time that analysis included the cost of the added APU cycle as well as fuel use. Not sure what the numbers are now or if the S80 fleet even has a published break even number (738s do not); however, it is supposed to be AA policy to NOT operate the APU upon arrival and I suspect the crew was simply waiting for the ground power to be applied.
*NO CARRIER* -- A Naval Aviator's worst nightmare!
 
IAHFLYR
Topic Author
Posts: 3943
Joined: Sat Jun 25, 2005 12:56 am

RE: AA Super 80 Gate Engine Shutdown Proc.

Wed Jan 24, 2007 12:28 pm

Quoting AAR90 (Reply 5):
however, it is supposed to be AA policy to NOT operate the APU upon arrival and I suspect the crew was simply waiting for the ground power to be applied.

Thank you very much for your insight.
Any views shared are strictly my own and do not a represent those of any former employer.
 
twal1011727
Posts: 449
Joined: Thu Mar 23, 2006 5:36 am

RE: AA Super 80 Gate Engine Shutdown Proc.

Sun Jan 28, 2007 1:32 am

Most newer style (less than 20 yrs old) jetbridges have a circuit that will not allow the jetbridge to move towards the A/C if the power cable is lowered. When the power is turned on total movement of the jetbridge is inhibited.
This is so a gate agent cannot pull the jetbridge off the A/C while the power is still connected to the A/C.

Airlines that want to save cycles/fuel on the APU will leave the APU off and accept an engine running the 1-3 minutes it takes to hook up power

KD
 
SlamClick
Posts: 9576
Joined: Sun Nov 23, 2003 7:09 am

RE: AA Super 80 Gate Engine Shutdown Proc.

Sun Jan 28, 2007 2:15 am

Quoting AAR90 (Reply 5):
policy to NOT operate the APU upon arrival and I suspect the crew was simply waiting for the ground power to be applied.

That was my first thought. Coupled with this fact:

Quoting TWAL1011727 (Reply 7):
jetbridges have a circuit that will not allow the jetbridge to move towards the A/C if the power cable is lowered.

A couple other things that might be going on at some airport or other out there in the world are Union slowdowns by certain ground personnel and local airport noise regulations prohibiting the running of APUs unless ground power and air are not available.
Happiness is not seeing another trite Ste. Maarten photo all week long.
 
flametech21
Posts: 46
Joined: Mon Sep 18, 2006 9:08 am

RE: AA Super 80 Gate Engine Shutdown Proc.

Thu Feb 01, 2007 12:36 pm

Wow, I somehow missed this one.

AAR90 is correct, we are under strict orders not to run the APU at the ramp. It is unwritten law to leave the taxi engine running until external power is hooked up. And at some airports such as IAH, that can take a few minutes.

FYI the S80's do not have a specific break even number, although there is simple equation you can use to calculate a ballpark estimate.

Sean, an AA ops eng.
They build them to a higher standard at Long Beach!

Who is online

Users browsing this forum: Apprentice, ikolkyo and 12 guests