flyinTLow
Posts: 455
Joined: Tue Oct 12, 2004 10:40 pm

AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Thu Jan 08, 2009 11:34 am

sorry if this has been posted before, couldn't find anything through the search:

AirDisaster.com:

Quote:
Warning issued to airlines flying Airbuses
The Dominion Post

An emergency safety directive has been issued to airlines using twin-engine Airbus A320s after both engines on one stalled over the Mediterranean, just 18 days after an Air New Zealand A320 crashed killing all seven on board.

However, an Air New Zealand spokesman said its A320s, including the one that crashed, are equipped with rival International Aero Engine V2500s plant.

The directive from European and United States aviation authorities, comes as mystery continues as to the cause of the Air New Zealand crash off the coast of southern France.

Five New Zealanders and two Germans died in the November 28 crash during a test flight.

On December 14, an Air France Airbus A321 a stretched version of the A320 suffered a double engine stall as it climbed out of Tunisia, bound for Paris.

Passengers heard loud bangs from both of its CFM International 56 engines and the stalling occurred as pilots eased back on power.

The engines are designed to not close down on stalling and power was quickly resumed. The aircraft made a safe emergency landing.

The safety directive calls for airlines with about 1500 Airbuses to urgently check and repair high-pressure compressor fans on CFM 56s on A318s, A319s, A320s and A321s.

European authorities said that since April last year, six different engines used by three operators had stalled. These were followed by the Air France incident.

American authorities warned such stalling problems "could prevent continued safe flight or landing".

Meanwhile, on January 13 the French crash authority, the Bureau d'Enquetes et d'Analyses (BEA), will hold a Paris meeting in a bid to move the Air New Zealand investigation forward.

Aviation sources say it is coming under pressure to come up with an explanation as the A320 is a European and North American commuter workhorse. Concern was already mounting following an October incident with a Qantas Airbus A330 that lost altitude after going into a dive, injuring 40.

A safety directive on software was issued for A320s last month.

The Air New Zealand plane plunged into the sea without issuing a distress call. Six of the seven bodies have been recovered but are still undergoing dna testing for identification.




Does anybody know more about this? About the dual engine stall and about the safety directive?

Cheers,
Thilo
- When dreams take flight, follow them -
 
PhilSquares
Posts: 3371
Joined: Sun Mar 28, 2004 6:06 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Thu Jan 08, 2009 11:40 am

Quoting FlyinTLow (Thread starter):
Does anybody know more about this? About the dual engine stall and about the safety directive?

The quote you provide is somewhat in error. The AD applies to CFM56 series powered aircraft not to just the 320.
http://www.airweb.faa.gov/Regulatory...BEE5086257530004EC0A4?OpenDocument
It only applies where both installed engines have a greater than 80C deterioration of the EGT margins.

[Edited 2009-01-08 04:03:47]

[Edited 2009-01-08 04:05:16]
Fly fast, live slow
 
bennett123
Posts: 7442
Joined: Sun Aug 15, 2004 12:49 am

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Thu Jan 08, 2009 11:55 am

The link to the A330 is not completely clear.

"airlines using twin-engine Airbus A320s". What other sort of A320's are there.
 
AC320tech
Posts: 193
Joined: Mon Jul 31, 2006 6:32 am

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Fri Jan 09, 2009 3:45 am

What's interesting about the XL Germany 320 incident is that it is now being considered a crime scene, and the wreckage is in tiny pieces. If the engines stalled, you would think the pieces left behind would be bigger, like Air Florida 90 (even though QH90 stalled), as the plane would glide, not plunge.

http://www.stuff.co.nz/4778986a11.html
 
User avatar
SEPilot
Posts: 4962
Joined: Sat Dec 30, 2006 10:21 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Fri Jan 09, 2009 2:38 pm



Quoting PhilSquares (Reply 1):
The AD applies to CFM56 series powered aircraft not to just the 320.

It seems to be limited to those variants of the CFM56 variants on the A320 series. Since all 737's except the Jurassics use CFM56's as well, if they were affected it seems that the AD would at least mention them, but it doesn't. What is the difference besides fan diameter between them; or is the larger fan diameter at the root of this problem?
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
PhilSquares
Posts: 3371
Joined: Sun Mar 28, 2004 6:06 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Fri Jan 09, 2009 3:55 pm



Quoting SEPilot (Reply 4):
It seems to be limited to those variants of the CFM56 variants on the A320 series. Since all 737's except the Jurassics use CFM56's as well, if they were affected it seems that the AD would at least mention them, but it doesn't. What is the difference besides fan diameter between them; or is the larger fan diameter at the root of this problem?

My point was the AD is for the CFM, not for the A320 series. If the AD was for a specific aircraft type it would say just that.
Fly fast, live slow
 
User avatar
SEPilot
Posts: 4962
Joined: Sat Dec 30, 2006 10:21 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Fri Jan 09, 2009 8:32 pm



Quoting PhilSquares (Reply 5):
My point was the AD is for the CFM, not for the A320 series. If the AD was for a specific aircraft type it would say just that.

I realize that. My point is that it seems to be only the variants of the CFM-56 that are used on the A320, and I was wondering why other variations (such as those used on the 737) do not seem to be affected, and whether it was related to fan diameter.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
User avatar
zeke
Posts: 9854
Joined: Thu Dec 14, 2006 1:42 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Sat Jan 10, 2009 3:33 am



Quoting SEPilot (Reply 6):

The FAA AD did not explain the issue as well as the EASA one.

"Applicability: A318-111, A318-112, A319-111, A319-112, A319-115, A320-214, A320-215, A320-216, A321-111, A321-112, A321-211, A321-212, and A321-213 aircraft models, all serial numbers with CFM56-5B engines installed.

Reason: Several in service occurrences of HPC stalls have been reported by operators of Airbus aircraft fitted with CFM 56-5B engines since January 2007. Root cause is highly deteriorated HPCs. To improve operability and maintainability CFM released ECU software 5BQ in January 2007 which features 2 degrees additional Variable Stator Vanes closure in the low power region to increase the stall margin. This 5BQ software introduction has reduced the frequency of stalls, however since April 2008, 6 different engines with 5BQ software have experienced stalls at 3 different operators.

On 15 December a CFM56-5B powered A321 experienced stalls on both engines during the same flight. This event was caused by a high level of HPC deterioration.

Stalls on both engines during flight can cause a dual IFSD.

AD 2008-0227-E has been issued, applicable to CFM56-5B engines, to require for aircraft with both engines indicating more than 80 degree Celsius (°C) of Exhaust Gas Temperature (EGT) margin deterioration, one of the engines to be replaced.

Further to additional investigations done by Airbus, it has been determined necessary to mandate additional aircraft level requirements for aircraft with both engines indicating an EGT margin deterioration above 75°C."

It would appear that operators want to leave the engines on the wing longer, and asked CFM to get a little more life out of them, CFM came out with the 5BQ software version. It would appear that operators were just doing a software update on the engine and not look at the level of deterioration of the high pressure compressor, the software update does not appear to be able to cope with a lot of HPC deterioration.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
User avatar
SEPilot
Posts: 4962
Joined: Sat Dec 30, 2006 10:21 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Sat Jan 10, 2009 9:08 pm



Quoting Zeke (Reply 7):
The FAA AD did not explain the issue as well as the EASA one.

Thanks for the info, but I still don't understand why it applied to CFM-56's on A320's but not on 737's.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
tdscanuck
Posts: 8572
Joined: Wed Jan 11, 2006 7:25 am

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Sat Jan 10, 2009 10:00 pm



Quoting SEPilot (Reply 8):
Thanks for the info, but I still don't understand why it applied to CFM-56's on A320's but not on 737's.

The -5 and -7 have different fans, and hence almost certainly have different compressor scheduling. It may be that whatever allows a -5 to surge when you've still got EGT margin isn't outside the envelope on a -7.

You can be certain that CFM is checking that right now to make sure they don't have a problem on other models, if they haven't already.

Tom.
 
User avatar
SEPilot
Posts: 4962
Joined: Sat Dec 30, 2006 10:21 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Sun Jan 11, 2009 4:52 pm



Quoting Tdscanuck (Reply 9):
The -5 and -7 have different fans, and hence almost certainly have different compressor scheduling. It may be that whatever allows a -5 to surge when you've still got EGT margin isn't outside the envelope on a -7.

I suspected as much; thanks for the info. My interpretation is that there still ain't no free lunch; the larger diameter fan gives you better efficiency but at the cost of decreased margins elsewhere. One of the unavoidable tradeoffs in engine design.
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
 
tdscanuck
Posts: 8572
Joined: Wed Jan 11, 2006 7:25 am

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Sun Jan 11, 2009 6:20 pm



Quoting SEPilot (Reply 10):
My interpretation is that there still ain't no free lunch; the larger diameter fan gives you better efficiency but at the cost of decreased margins elsewhere. One of the unavoidable tradeoffs in engine design.

That's my understanding too. If there are no core changes in the -5, then they must be running the turbines harder to drive the bigger fan, which means they must run the compressor harder to feed the turbines. Normally, EGT is a good indicator of engine health but it seems like the -5 may be in a semi unique situation where the compressor can degrade to the point of stalling fairly early in the EGT margin dropoff.

Tom.
 
User avatar
Francoflier
Posts: 3702
Joined: Wed Oct 31, 2001 12:27 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Mon Jan 12, 2009 10:27 am



Quoting Tdscanuck (Reply 11):
the -5 may be in a semi unique situation where the compressor can degrade to the point of stalling fairly early in the EGT margin dropoff.

Or could it be that said EGT dropoff margin has been stretched a bit too far due to operator demanding to keep their engines on-wing longer...?
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
tdscanuck
Posts: 8572
Joined: Wed Jan 11, 2006 7:25 am

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Tue Jan 13, 2009 12:44 am



Quoting Francoflier (Reply 12):

Or could it be that said EGT dropoff margin has been stretched a bit too far due to operator demanding to keep their engines on-wing longer...?

Could be...I'm not sure what the critical EGT value is driven by on the -5...could be turbine inlet temperature, could be compressor degradation. It looks like maybe they picked the wrong end-point.

Tom.
 
User avatar
Francoflier
Posts: 3702
Joined: Wed Oct 31, 2001 12:27 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Tue Jan 13, 2009 6:19 am



Quoting Tdscanuck (Reply 13):
It looks like maybe they picked the wrong end-point.

Agreed.

I wonder if that degradation margin has been set all along or has been extended from a lower initial value following on wing engine monitoring with operators.
I'll do my own airline. With Blackjack. And hookers. In fact, forget the airline.
 
phatty3374
Posts: 64
Joined: Thu Apr 21, 2005 5:30 am

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Sat Jan 17, 2009 2:48 am

I know this is completely unrelated to the problems discussed in this thread, but as I was browsing the Tech Ops forum topics, I found this one somewhat ironic considering the US A320 incident. Of course the causes are absolutely unassociated, but I thought it was interesting considering both incidents involved dual engine problems. No?
 
User avatar
zeke
Posts: 9854
Joined: Thu Dec 14, 2006 1:42 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Sat Jan 17, 2009 2:54 am



Quoting Phatty3374 (Reply 15):
Of course the causes are absolutely unassociated, but I thought it was interesting considering both incidents involved dual engine problems.

Yes no doubt a new AD only applicable to A320 series aircraft with CFM56-5B4/P engines installed asking for the and inspection and removal of all Canadian Geese from the CFM56-5B4/P engines before further flight.
We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar
 
jetlife2
Posts: 183
Joined: Sun Jul 09, 2006 11:32 am

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Sat Jan 17, 2009 3:36 am



Quoting Zeke (Reply 16):
....asking for the and inspection and removal of all Canadian Geese from the CFM56-5B4/P engines before further flight.

 laughing 
My views are not necessarily the views of the GE Company
 
User avatar
SEPilot
Posts: 4962
Joined: Sat Dec 30, 2006 10:21 pm

RE: AF A320 Dual Engine Stall / JAA-FAA A320 Directive

Mon Jan 19, 2009 12:12 am



Quoting Zeke (Reply 16):

Yes no doubt a new AD only applicable to A320 series aircraft with CFM56-5B4/P engines installed asking for the and inspection and removal of all Canadian Geese from the CFM56-5B4/P engines before further flight.

Excellent idea; how about adding provisions for removing them in flight? Better yet, how about equipping the planes with nose guns to shoot the bloomin' things down?
The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler

Who is online

Users browsing this forum: BreninTW, TailDragging and 18 guests