All planes with more than one engine is supposed to be able to continue to fly with one of them not working. I know that should be obvious, but just in case...
low cycle fatigue (LCF) fracture
time since new (TSN)
cycles since new (CSN)
Overhaul & Repair (O&R)
fluorescent penetrant inspection (FPI)
thermal acoustic imaging (TAI)
Principal Maintenance Inspector (PMI)
Fan Blade Off (FBO)
Maintenance Observation Program (MOP)
Flight Safety Foundation (FSF)
Maintenance Observation Program (MOP)
and, there's likely a couple that I missed...
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
Since entering revenue service in 1987, Pratt & Whitney has delivered more than 2,500 PW4000-94'' engines that have collectively logged more than 120 million dependable flight hours on commercial aircraft around the world.
The Boeing 777 does not use the PW4000-94". It uses the larger PW4000-112" engine (the one I showed on my 21 Feb 21 06:15 post). I may be wrong, but I think it's the larger engine that uses the hollow blades. The larger diameter main fan wheel increase the rotational forces on the blades, thus the need to lighten the rotating mass.
A bunch... and when you think of a turbine at high RPMs, a bunch more...(This was the article I had to look up the abbreviations for)
According to United Airlines’ maintenance records, the No. 2 engine had accumulated 77,593 hours time since new (TSN) and 13,921 cycles since new (CSN) and 8,579 hours and 1,464 cycles since the last overhaul. The engine was installed on the airplane on October 18, 2015 [and] had operated 8,579 hours and 1,464 cycles since it had been installed. The entire fan blade set, including fan blade No. 11 had last been overhauled by P&W’s Overhaul & Repair (O&R) facility in July 2015. As part of the overhaul process, the blades underwent a fluorescent penetrant inspection (FPI) and a thermal acoustic imaging (TAI) inspection. P&W developed the TAI inspection process in about 2005 to be able to inspect the interior surfaces of the hollow core PW4000 fan blade. The records for the TAI inspection in July 2015 as well as an earlier TAI accomplished in March 2010 revealed a thermal indication in the same location as where the LCF crack occurred. The records for the fractured fan blade’s July 2015 TAI inspection was annotated ‘paint’ that, according to the inspector, was consistent with him accepting the indication because he thought it was an issue with the paint.
Rather than think climate change and the corona virus as science, think of it as the wrath of God. Feel any better?
Its normal with a 747 in some situations that they can continue.
In the US though there was up roar 10 years ago or so when BA had to shut one down after departure and continued across the Atlantic. it had to land in Manchester instead of Heathrow because of the increased fuel burn.
There was calls for the Pilot in command to be jailed.
The USA works with a dispatcher system where some licensed person on the ground can tell the crew what to do. In UK and Europe we have a flight dispatch system where they prepare all the paper work etc and then give it to the pilots and monitor things for any changes and try to keep things smooth. But all decisions are made by the pilots they just provide information. There was a bit of an issue with the US flight dispatcher telling them to land and it being ignored.
So the crew checked the manuals spoke to ops and continued.
It was just when the EU compensation had kicked in so continuing saved them quarter of a million.
Eventually after months they decided that they hadn't actually broken any rules. But afterwards the FAA changed the rules so in the USA airspace you have to land in the event of power loss. Before that as long as you didn't loose more than 50% performance you could continue. But then it screwed quite a few company's up and they wanted to change it back... But I don't know if they did or not. What they really wanted was one set of rules for N reg and one set for everyone else.
I believe you can't do it with a A340 or A380 because you loose to many system backups and once you run the checklists for those it tells you to land at nearest suitable airport.
Dik, it seems the fan spins around 2000 rpm and other sections in the engine approach 12k rpm. These numbers are from there triple redline test of the GE 90 series engine. I assume PW 4000 numbers are similar.
I dont think I would need a checklist, or a dispatcher. Da. Something's bigly wrong there.
When one engine blows, do you really believe that you still have theoretical reliability and confidence level in the other. I'd at least divide by 2, 'cause IMO you are more than half way towards seeing a black swan appear.
Put it this way if I had an engine shut down on me over Afghanistan or over some other choice countries in Africa and everything was working I wouldn't be landing at the nearest airport.
If I was just over the Alps heading north and everything was working and no structural damage after the engine was secure the conversation on the flight deck would quiet quickly move onto the pro and cons of currywurst over bratwurst in Munich Airport where we would be landing.
A mate of mine lost an engine over head Glasgow and landed in Birmingham. When asked by the AIBB why did you land there and fly past Liverpool and Manchester etc.
I don't know what a nominal tip speed is for a fan but Alistair's 430m/s sounds pretty reasonable. You can bet that all fans of similar technology run similar tip speeds at their design point. RPM follows from tip speed, QED.
"Schiefgehen wird, was schiefgehen kann" - das Murphygesetz
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