Thai Airways Boeing 777 Suffers Uncontained Engine Failure In Bangkok
 

A Thai Airways Boeing 777 suffered an uncontained engine failure in the early hours of yesterday morning. The aircraft was not airborne at the time, and as such abandoned its takeoff attempt.

A Thai Airways flight to Zurich was hit by a 12-hour delay yesterday. The reason for the delay was an uncontained engine failure during takeoff. Thankfully, the aircraft was able to slow down enough on the runway to return to the terminal, albeit on the other side. According to photos shared on social media, a huge hole was visible in the side of the engine.

https://cimg8.ibsrv.net/gimg/pprune....2920aa0a87.jpg


https://simpleflying.com/thai-uncont...ngine-failure/

Reportedly a GE90 powered B773, according to Avherald, though that combination doesn't actually exist.

So it's a B77W? I think the main reason for a different code is that the 300ER has an increased wingspan, not due to the different type of engines.

Assuming that the operator has been correctly reported as Thai, it's either a Trent-powered B773 or a GE-powered B77W. The photo doesn't look like it's a Trent.

ICAO designators are assigned primarily on the basis of performance differences that are relevant to ATC, for example the extra 30,000 lbf of thrust on the B77W.

It seems, from the Avherald report, that the aircraft was HS-TKL which is equipped with GE90-115B engines.
Pictured here at Heathrow:
http://www.kelvindavies.co.uk/kelvin/details.php?image_id=27080

Thrust to weight would be more interesting, as it drives climb performance. Unfortunately ATC doesn't now the actual aircraft weight. Wingspan is important for stand planning as a stand for a 773 might not fit a 77W. I have heard of cases where this mixup almost caused the loss of a winglet.

Indeed so.

Though normally airport stands are classified by ICAO Code Letter, the second part of which determines which aircraft type(s) can be accommodated on a given stand. That, of course, is why the B77W was designed with a 64.8 m wingspan so that it would still fit on a Code E stand (up to 65 m span) as used by the rest of the 777 family.

Is the person using the specific 773 vs 77W code? Or using a generic short version of 773 for a 777-300 family aircraft?

At the risk of prolonging the thread drift, those are the IATA codes (see SSIM Appendix A) for, respectively, non-ER 777-300 and 777-300ER, equivalent to ICAO's B773/B77W. Neither IATA nor ICAO has a generic code that combines the two variants.

Anyway, the important question - now resolved - was whether the incident as reported involved one of Thai's B773s (all Trent-powered) or one of their B77Ws (in which case it can only have been a GE90).

It's now confirmed that it was the latter, no doubt much to Derby's relief.

Back on the safety issue....

The FAA issued an AD removing 8 GE90-115B engines from service.

The AD says the other engine was also damaged by the liberated turbine...


This emergency AD was prompted by an event that occurred on October 20, 2019, in which a Boeing Model 777-300ER airplane powered by GE GE90-115B model turbofan engines experienced an uncontained high-pressure turbine (HPT) failure that resulted in an aborted takeoff. Debris impacted the aircraft fuselage and the other engine. Uncontained HPT failure, if not addressed, could result in release of high-energy debris, damage to the engine, damage to the airplane, and possible loss of the airplane.

FAA EAD 2019-21-51: General Electric Company GE90-115B Turbofan Engine Models Fitted to B777-300ER Aircraft

WOW!

That EAD says it all really

"Possible loss of the airplane". if your unlucky to have an uncontained failure after V1 close to the ground

extremely low probability to connect all the necessary dots.

the rule basis typically addresses in-flight without regard for ricochet off the runway sufficient to take out the last remaining engine

The AD unsafe condition statement in the recent AD is the standard language used in FAA ADs for uncontained engine failure issues due to the potential for catastrophic damage to the airplane.

To elaborate a bit - the Advisory Circular for rotor burst requires a 'one-in-twenty' analysis - i.e. you need to show that the probability of catastrophic damage due to a rotor burst is no greater than 5% So, by definition, there is a small probability that any uncontained engine failure could be catastrophic.

Boeing 777 - 300ER Emergency Airworthiness Directive
 

Video was too long for the simple message of an AD being issued.

Raising questions about what he doesn't understand is not of much interest to the cause nor the corrective action.

That explanation of the engine design is not correct.

Well, I've learned something new. to me a 773 was a B777-300/300ER. I suspect to most people it is the same.

Anyway, where are all the RR haters? Strangely quiet I see. If this was a Trent there would be howls of 'time to ground this type' .
Hypocrisy.

A more detailed explanation, with visuals from a related engine (GE CF6), has been posted by an actual jet mechanic:

We're getting way too detailed in this thread and again much is wrong, although nice eye-candy. Again it doesn't add much to the thread subject regarding what failed and was uncontained , and why. The how and what fix is appropriate. is known by the manufacturer and the FAA.

There are many ways an inter-stage seal can screw up but causing an uncontained disk or blades in this case are unlikely. The interstage seal by itself can be liberated and be uncontained by spearing out through a localized hole in the engine case, like a spring hoop and be followed by broken blade debris in a shot-gun pattern. The seal itself may have sufficient energy to make it all the way across the distance to the other side of the fuselage by bouncing off the runway.

If more details of what actually did happen turn up then there may be room for discussion in this thread, but the videos above don't add answers to the fundamental questions regarding this incident.