Posted on 06/06/2006 9:54:34 PM PDT by UNGN
General Electric is investigating the cause of an apparent uncontained engine failure which caused extensive damage to an American Airlines Boeing 767-200 at Los Angeles on Friday.
The aircraft (N330AA) was undergoing a ground run-up of the (left) No.1 engine when the problem occurred. The CF6-80A was being tested after the crew bringing the aircraft in from the New York reported abnormal power response from the engine during the flight.
Reports say the engine was at more than 90% power when the failure occurred, either in the shaft or the high pressure turbine (HPT) area. Judging by images of the incident that have since appeared on the Internet, it appears that an HPT disc ruptured, puncturing the fuel tank in the wing near the trailing edge, slicing partially through the belly of the aircraft and damaging the keel beam. The No.2 engine was also damaged by the exploding debris and the fuel tank on the right wing punctured.
The wing puncture also caused fuel to be spilled on the tarmac, and that along with a fuel line rupture caused a major fire which engulfed the wing and the rear fuselage before it was put out. Fortunately a Los Angeles airport fire department was close by, and got the fire under control while the the maintenance crew escaped The damage to the wing trailing edge, flaps, aft fuselage, fuel tanks on both sides and the keel beam makes it likely the aircraft will be declared a write-off. The surrounding runways and taxiways were closed off for some time immediately after the incident while a FOD search was carried out. Parts of the second HPT disc were reportedly still missing as of yesterday.
The CF6-80 has been hit by similar issues in the past, and as recently as January 2003 was the subject of a US Federal Aviation Administration airworthiness directive (AD) calling for inspections of the HPT disc. The AD was prompted by an incident on 8 December, 2002, when a 767-200 equipped with GE CF6-80A series engines experienced an uncontained failure of a stage 1 HPT rotor disc during climb. The FAA said at the time the “results of the investigation indicated that the stage 1 HPT rotor disc failure was the result of a crack that initiated in an aft corner edge of the bottom of a dovetail slot. The crack propagated in fatigue to critical crack size, and subsequently resulted in disc rupture and separation.”
The FAA also notes that in September 2000, a U.S. operator experienced a similar uncontained failure of the stage 1 HPT rotor disk during a ground maintenance run of a CF6-80C2 engine. Again it said “the investigation of that failure had indicated that a crack initiated in the dovetail slot bottom aft edge. The root cause of the crack initiation remains unknown. However, cracks, burrs, or damage sustained in the dovetail slot bottom corner radii from improper handling and processing during new part manufacture and/or during maintenance were suspect for the September 2000 event.”
A previous AD, which became effective in June 2001, was also issued to mandate inspections of the CF6-80C2 stage 1 HPT rotor disc dovetail slot bottoms.
Not to sound alarmist, but I'm thinking there are going to be some mass groundings of CF6-80A's in the near future. If I worked for GE, I'd be trying to excavate the masonary from my colon, about now.
Yikes! I hate it when that happens.
Not likely. Uncontained engine failures, while rare, do happen. Now if it suddenly started happening on multiple aircraft, then grounding might become a possibility.
Holy smack, Batman! That is quite the failure of the shaft!
Ping
Buy Magnaflux stock ASAP!
N330AA in happier times.
Un-contained failures don't normally take out BOTH engines and puncture the fuel tanks on BOTH wings AND the Belly tank. If this had happened on take off, there is a good change it would have been a fiery mess.
I'm not counting, but I would think this is the 4th HPT disk failure on this model in the last 6 years.. It's hard to find a root cause on some of the incidents, because the pieces of the disk were never found.
Thank God it happened on the ground during a maintenance check. It could have been messier. If I understand correctly, one engine trashed, damage to the other, a wing on fire, and keel beam damaged the 'landing' would not have been pretty.
There was one, a National Airlines DC-10-10, where the #1 engine broke apart and threw shrapnel in every direction, punctured the fuselage, which resulted in one passenger being ejected from the aircraft, and also damaged the #3 engine.
nearly twenty year old 767-200ER, that is looking like a write-off.
Bad example. How many D-10's are left with more than 4 people on board on any given flight? 5? 2?
Two more of these on the ground or one in the air and the GE powered 767 is done. Stick a fork in it.
Take a look at the 777's containment system. It's a full wrap of layered Kevlar. No turbine components have ever made it out of that with damaging velocity.
You have to remember, the 767 is a 70's design, and this was one of the older models.
Your statements show that you really need to learn a lot when it comes to aviation. If you think a single engine failure is going to be the end of GE powered aircraft, you're very mistaken.
Considering the 767-200ER shares engines with the 747-400, could it be possible to cause a chain reaction failure of all four engines on one GE powered 747-400?
Doesn't the 747-400 use the -80C version of this engine, which has a different HPF (the troublesome component)? If so, I'd say that it wouldn't be affected by this problem.
It's possible to do so, of course, depending on who's maintaining the aircraft and how careful they are - but that's not GE's or Boeing's fault.
Just checked - the 747-400 uses (among others) the CF6-80C2B5F turbofan engines, with 62,100lb maximum thrust. The -80A series is what's mentioned as giving trouble here.
HPF/HPT...
This must be an older 767-200ER. The Boeing website lists the GE CF6-80C2B7F as one of two engines available. Airlines that operate both 767's and 747's often use the same engine pool for both aircraft. Supposedly that was one of the considerations for UPS making its big orders of 747-400F last year.
According to airfleets.net, N330AA was/is a 767-223ER with a first flight date of 25 Feb 1987 and a delivery date of 13 Mar 1987.
Background: The parent 767-200 series first flew on 26 Sept 1981, and entered service on 26 Sept 1982. The767-200ER series first flew on 6 Mar 1984.
This airplane is an early-model 767-200ER series with (apparently) the original engine type.
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.