Too close to EWR for dumping. I lived off Exit 12 for a lot of years. Back then trucks leaked fuel like crazy since it was so cheap and mileage wasn't an issue like today. Turnpike would be always be slippery when it started to rain.
United 108 IAD-MUC Engine failure at 1,000 feet on takeoff
- Thread starter Astro14
- Start date
- Joined
- Oct 25, 2021
- Messages
- 2,243
I see
- Joined
- Oct 25, 2021
- Messages
- 2,243
So basically, fuel was cutoff? Not actually anything mechanical with the engine then
It could be a variety of things. I'm no expert, but these engines are complicated. Reliable, but very complicated. Might have been a part that rarely fails but was easy and quick to diagnose, access, and replace? Who knows?
Isn't this sort of thing supposed to be caught during routine maintenance/inspections? Of course that doesn't preclude the possibility of random failure that wasn't a result of normal wear that would indicate the possibility of failure before the next inspection.
Inspections look for things that are defective….you can’t see some things that are working now, but will fail in the future.
The engines, the entire airplane, gets inspected and checked before going ETOPS/International. Every flight. Every time. This airplane was no exception.
I once had a 767-300 going to London one night, we were 5 minutes from pushback when the cabin temperature got warm, and I mean really warm. We had started boarding 45 minutes prior, and everything was working fine. Long story short - we couldn't fix it, and had to get another airplane. I stood by the door as folks deplaned.
One upset passenger, a tall, British person from 1st class, said, in an imperious, condescending voice, "this should have been discovered 3 hours ago!" I looked at him and said, "The airplane was thoroughly checked hours ago, but this fault didn't appear until 5 minutes prior to departure."
"Unacceptable!" he roared.
The next guy said, with a smirk, "You mean that you can't predict the future?"
Exactly.
Not exactly - the fuel was being improperly metered into the engine. The engine temperature was too high, the thrust was too low, the whole thing wasn't running right, so, it had to be shut down. jet engines aren't exactly like cars - there isn't a good analog.
There are some things that are hard to detect without disassembly or at least ultrasonic inspection. But yeah I think we all appreciate the safety checks that go into modern aviation.
Too bad you can't tell that bloke to go stuff himself.
- Joined
- Oct 25, 2021
- Messages
- 2,243
Gotcha, that makes more sense.
The bypass ratio on the GeNX engine is like 9:1 - which is crazy high. Much higher than previous generations of airliner engines.Gotcha, that makes more sense.
It enables the 787 to get really incredible fuel economy. The 787 carries about as many people as the 767, but flies about 6-8000 feet higher, about 40 MPH faster, and uses half the fuel. Yep, twice the economy, at higher speed and altitude.
Amazing engine.
But, the aerodynamic/pressure balance between N1 and N2 (the two spools, inside the engine) has to be maintained exactly - and that is harder to do as the bypass ratio goes up. So, while I don’t know exactly what went wrong with this engine - improper metering of the fuel could cause an upset in that balance, nothing wrong with the engine mechanically, but it was running too hot, and not making any thrust.
So, it failed, in that sense. It wasn’t making thrust, and the exact reason becomes important only after the airplane is on the ground.
With electronic checklists and prescribed procedures built into the jet, I suspect that the engine told the airplane it wasn’t able to be restarted in flight, or the “engine relight” checklist would have been offered after the engine was shutdown. An engine relight may have been part of the other checklists they ran, but again, the engine wasn’t capable of being relit with that failed component (kind of like an engine start isn’t possible if the fuel injection isn’t supplying fuel).
So, they shut it down and left it off. The longer an engine runs with abnormal parameters, particularly EGT, the more likely it is to be damaged. Heating isn’t even when the airflow though the engine is disrupted, so you can get “hot spots”, where the local temperature is higher than the recorded temperature, and those hot spots can damage turbine blades and other components.
The fact that the engine flew the next day tells me that the crew acted quickly and correctly. Their quick action prevented thermal damage to critical components.
