UA 777 engine cowling comes off in flight

40 minutes out of Honolulu.

Not like there were choices.

 

Closest... they were only 40 minutes from Honolulu.

 

Didn't see that number quoted in the OP link. So great, they flew to the nearest airport. Agree that at certain points in the Earth there can be few choices, which is why they have pushed ETOPS out to 180min (or more).

 

Hahaha omg that's an understatement

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How does the pilot get notified in these situations? Does an alarm go off in the cockpit? Or is it the screaming if the passengers and the flight attendants running forward to tell the Captain ?

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"Well there's your problem, boys..."

JP

(Who is flying on an ANA 777 from Tokyo to ORD tomorrow morning!)

 

My concern is not that the cowling itself missing, but what if on its way off the plane it hit some structural and damaged that? It probably went straight up and/or down and crucial hydraulics are covered elsewhere in the wings, but that 1 in 1,000,000 chance it hit something it shouldn't have. I'll have to follow this up and see if they find damage elsewhere, but preliminary it doesn't appear to have happened.

The SWA 737 had a blade puncture the fuselage I think, but that was a spinning part and much more likely to travel toward the plane unlike this cowling that doesn't spin.

 

Instruments will indicate which engine is failing, vibrations noted by the flight crew, observation from the flight deck. I just finished a conversation with a pilot who flies the Pacific and I was told that the vibrating engine would be secured ( shut down) and the flight would continue to the destination. Quote, " That airplane can fly all day on one engine while the other is shut down. Single engine landing is a piece of cake. It's really not that big of a deal." From looking at videos, it appears that the engine was windmilling because of the low frequency of the oscillations so apparently it did ingest some debris from the cowling as it disintegrated.

 

I'll bet that United is already checking all the cowling latches on all their other 777s...

 

Hah.... You think just United???? ...and 747-400's, MD-11's, 767's, A300's, A310, etc. etc. that all use the same engine and cowling???

 

Thanks for that answer, Bob...
I asked about this earlier... hoping someone would respond.

 

Yep, turbo-fans are not the same as prop. Securing simply means shutting off the gas supply. Nothing to feather so the fan continues to rotate, i.e. windmill. This adds considerable drag, and if there is any imbalance due to damage appreciable vibration.

The cumulative fatigue damage due to this vibration can be critical, depending on the level of vibration and remaining flight time. This is evaluated entirely by analysis using multiple assumptions regarding damage scenario and resulting (vibratory) loads. It is also not just the engine and pylon that are effected. As seen in the passenger video the vibration was evident in the cabin. Many details throughout the entire airplane can be impacted by the vibration and undergo analysis for this scenario. As a passenger you just need to hope that the actual damage is enveloped by the analysis that was considered.

 

Mayor, Bob is right, this is truly a non event in real airworthiness terms. Put it this way, if the hood flew off your car would you be in fear of your life driving it home? Its about the same thing basically. Continuing to his destination was the correct course of action if he was by his equal time point...

 

I don't know, it would be more like the front end of the car missing with a bunch of hydraulic lines in front of the radiator driving 500mph.

Couldn't the wind/vibration damage any of that stuff with no cowl?

 

Well, I can stop my car on the side of the road and call a tow truck

Tell me how I do that 4 hours out of Narita....

The point is that the fear of the unknown would scare the crap out of anyone. The engineers go "hey it's a non event" but the passengers go "Holy s**t!"

It would scare the pants off of me and I understand exactly what this means. But its the fear of the unknown that is the killer.

 

To be more specific, there are vibration sensors as well as the crew sensing vibrations. They could also possibly note fluctuations in compressor speeds and engine pressure ratios. Recent information shows that the fan lost a blade and that started it all. So the engine was secured before any structural damage could occur.

 

Actually they could have went to Kona or Kahalui if need be. I flew Hawaii for AA for 10 years and am pretty familiar with the lay of the land. Neither of those would offer terribly good maintenance alternatives though.

 

There are no hydraulic lines the forward part of the cowling area.

 

Not over the fan or inlet cowl. However if you view the very first pic in the OP link you will observe fluid spray over the core cowl aft of the fwd pylon-to-engine attachment fitting.

Hey, they were over water. It was only a bit over 500 lb of structure that fell off. (Note: each half of the fan cowl is approx 250 lb and the inlet cowl, not all of which departed, is approx 700 lb)

Surprising, actually not, that the blade containment, the brown (kevlar) 'wrapping' around the fan case in the photos, shows no damage. If you've ever seen the videos of blade'loss testing the deformation and resulting damage to the structure is significant and obvious, even 180deg opposite of where the blade impacts. The not surprising part is that the blade can actually travel fwd when it fails, i.e. detaches from the rotor hub, and thus can miss the containment feature entirely. In this case taking out a large portion of the inlet cowl which then resulted in the fan cowls being ripped off.

I hope I am never a passenger on an airplane with this crew member in the cockpit. This was not a normal engine shutdown, and significant structural damage did occur.

 

Compared what happened to the Connie back in the days its nothing:
http://www.historynet.com/the-legendary-lockheed-constellation.htm

In 1946 a Pan Am Connie en route from New York to London had an engine fire soon enough after takeoff that the airplane was able to return and belly-land on a 4,500-foot grass strip in Willimantic, Conn. There were no injuries to the crew or passengers, which included Laurence Olivier, his then-wife Vivian Leigh and other members of the Old Vic repertory company. The fire had burned through the engine mounts by the time the airplane was back over land, and the big radial and its prop dropped off entirely and fell onto a farm field. Fortunately for all on board, Lockheed, obviously aware of the flammability of the Wright engines, had designed the Constellation’s nacelles and stainless steel firewalls to encapsulate even a raging fire for 30 minutes.

 

I think I read that Lockheed also designed those engine mounts out of magnesium so they would burn through and drop the engine before it could damage the wing....

 

The KC-97 and B-50 also had magnesium engine mounts that would burn through and allow the engine to drop off. in case of fire. Both powered by P&W R4360's. I'm stretching my memory here but I believe that the Boeing jets all have shear pins that will allow the engine to separate in severe vibrations. The 707's had shear pins in the strut-to-wing connections to allow the strut to swivel upward in gearer-up landings to keep the wing from being punctured. The main gear also had shear pins to keep the wing tanks intact in case of the gear hit something.

 

My conversation was with three pilots of the line. They all said the same thing regarding the shut down of the engine and subsequent flight operations. The UAL crew followed company published procedures and protocols.

 

Educate us. What significant structural damage? Again, those with whom I spoke about this incident are three pilots of the line and they all said the same thing that the UAL crew acted within established procedures and got the airplane down safely. Not one of them thought that it was a big deal.

 

I guess the FAA doesn't think it is a big deal either

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_25_362-1.pdf

https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_25-24.pdf

I don't suppose your pilot friends think that UAL232 was 'not a big deal'?

In addition, I have been in mtgs with the FAA and EASA where an applicant has stated that such an such is not primary structure and not a big deal if it departs the airplane. Neither the FAA or EASA accepted such a statement as a basis for certification.