Airxliban From Lebanon, joined Oct 2003, 4503 posts, RR: 54 Posted (3 years 7 months 3 weeks 4 days 15 hours ago) and read 7420 times:
I remember a post on here a while ago that discussed the fact that some airlines (BA and NZ come to mind) debut an engine on 767, then after they have done a certain number of hours, transfer them to their 747-400s and remove some modules that are for one reason or another specific to ETOPS.
I spent most of the night looking for this thread, but couldn't find it. Apologies if it still exists out there.
Anyway, the question was -
1. Is it in fact the case that engines get transferred from 767s to 747s in the fleet of some operators?
2. If so, at what point are the engines taken off the 767?
3. Where does the 767 get new engines from?
4. What if any modules are taken off/modifications are made to the engines in order to put them on the 747-400?
MarkC From United States of America, joined Apr 2006, 259 posts, RR: 0 Reply 2, posted (3 years 7 months 3 weeks 4 days 2 hours ago) and read 6941 times:
There is a large PW4000 747 and 767 operator who also freely changes these engines between the types, along with the thrust rating plugs. On a 4000, the Boeing installations are identical and interchangable. The MD and Airbus have different interfaces. But, a 4052 is a 4056, is a 4060, is a 4062 with a simple plug change. Assuming all the internal components are configured for the thrust rating, which they most likely would be.
Completely different. B757 engines are smaller than B767 engines, with much lower thrust rating.
BA has the same RB211-524 on B744 and B767. They are interchanged between the fleets.
It takes about 4 hours to reconfigure the engine. The ETOPS engine has an extra oil px sensor, which is deactivated for the B744, and the thrust reverser cascades are changed (they are part of the engine on the RB211). And that is about all.
On the RB211 series of engines, except the-535 on the B757, the thrust reverser is part of the engine. There are no C ducts. When you want to work on the combustion section, or the bleed valves etc, you crawl inside the engine.
It makes boroscopes very comfortable, just lie in the bypass duct!
The -535 has a much smaller bypass duct, so has opening C ducts like all PW and GE engines.
rmm From Australia, joined Feb 2001, 521 posts, RR: 1 Reply 10, posted (3 years 7 months 1 week 4 days 11 hours ago) and read 4905 times:
I'm not sure that QF transfer the engines between the 767 and 747. I know they used to do it on the 733 & 734 fleet sometime back. When a 734 engine became EGT marginal at 23,500 lb thrust it would be removed and derated to 22,000 lb and used as a spare for the 733 fleet. From memory all the 747 thrust reverser's are white in color and the 767 one's are grey. As the t/rev is part of the RB211 engine I can't say I've seen a white reverser on a 767 or vice versa.
As for the GE powered 747 & 767 all the 744's are FADEC and only 1 767 is, the rest are PMC type engines. So I'm guessing very limited interchange takes place there.
Tristarsteve From Sweden, joined Nov 2005, 3855 posts, RR: 34 Reply 11, posted (3 years 7 months 1 week 4 days 4 hours ago) and read 4813 times:
Quoting rmm (Reply 10): From memory all the 747 thrust reversers are white in color and the 767 one's are grey. As the t/rev is part of the RB211 engine I can't say I've seen a white reverser on a 767 or vice versa.
When you fit an engine to the aircraft, you have to hand the thrust reverser. The cascade vanes are different part numbers in different positions on different engines. On the RB211 it is important to remember this, as once you have removed the engine, you can't get the cascade vanes out when it is sitting in it's stand on the floor!
So if you are changing a nbr 2 engine on a B767, and the engine that arrives from the shop is a Nbr 1, you probably have to change about 10 cascade vanes. You must remove these on the wing before you start removing the engine as the reverser has to be fully deployed to get them out. There is another problem as you must leave at least 4 fitted to stop the reverser twisting! If the engine change is planned, this is done in the engine workshop.
PW and GE engines are different, as the reverser is hanging on the wing, and is not part of the engine. Same on the RR Trents.
Zkpilot From New Zealand, joined Mar 2006, 4749 posts, RR: 10 Reply 12, posted (3 years 7 months 1 week 2 days 21 hours ago) and read 4530 times:
The main reason why this is done is for ETOPs reasons. That is put a brand new engine on an ETOPs aircraft (767) so that there is less chance it will develop a problem/need an inflight shutdown. Since a 744 has 4 engines this is not really an issue for it also since 744s tend to operate longer sectors and less cycles it means longer engine life to use over the engines middle-sunset years whilst keeping the new engines on the 767.
MarkC From United States of America, joined Apr 2006, 259 posts, RR: 0 Reply 13, posted (3 years 7 months 1 week 2 days 17 hours ago) and read 4474 times:
Its the ETOPs, but its also the EGT margin. If you had, say CFM56-5B's on a mixed A321 / A320 / A319 fleet, you would start out with the high margin engine on the 321, then, when it might not make power on that, you would bump it down to the lesser thrust rating. On that particular engine, the difference in thrust is big between the aircraft.
Ground turbines are essentially the same basic design, but using heavier cases. I know on the GG8, the wall thicknesses in the stators are very noticible compared to a JT8, but, they are also recognizable as JT8.
jetmech From Australia, joined Mar 2006, 2617 posts, RR: 53 Reply 14, posted (3 years 7 months 1 week 2 days 1 hour ago) and read 4310 times:
Quoting rmm (Reply 10): I'm not sure that QF transfer the engines between the 767 and 747.
I don't recall ever doing a direct transfer from a 767 to 747 or vice versa, but it should not really pose a problem if it needs to be done. The only mechanical operation I remember doing to a spare 524G2 before fitment to a 767 was removing a small fairing at the top of the Integrated Nozzle Assembly (INA). Apart from that, there would be the TR cascades as mentioned and anything additional required for ETOPS.
Quoting Tristarsteve (Reply 11): you can't get the cascade vanes out when it is sitting in it's stand on the floor!
The lower inlet cowling attach bolts are also one to look out for!
JetMech split the back of his pants. He can feel the wind in his hair.
Correct. And I believe the summing plug on the 767 commands a higher thrust rating than on a 747. Thus after submitting an engine to a higher thrust rating when new, the thrust rating is lowered after installation on a 747, therefor extending the engine the life.