Engine experts-advice please
 

Just wondering about the life span of aero engines-

Is replacement mandatory after a fixed number of cycles or can they be serviced/reconditioned indefinitely? Is there a manufacturer recommendation, is it operator discretion or is it prescribed by Regulatory Authority.

Many thanks

pretty much yes to all your questions if the aircraft has a private c of a then its abit different in that the engine is then on condition which means all the time it meets the spec and behaves itself, happy days.

gs

GS

Many thanks for taking the time to reply.

I travel quite a lot on the BA 777- I thnk the current ones have RR Trent 800 s ( the originals were GE) ?. I am always amazed at the size of these things. Is it right that a B737 nose could fit into one of these?

Thanks

The fan diameter of the GE-90 is around about 135 inches or so, I believe. The fuselage of a 737 is around about the 148 inch mark. This image gives a better idea of the scales involved.

Avionker,

Thanks for this - does show the size of these things.

I read somewhere that a pilot said that modern engines are so reliable that a cadet starting out now could very reasonably expect a career without ever experiencing an in- flight shutdown. Is that the (general) experience of current/retired pilots,I wonder

They can be overhauled/reconditioned indefinitely however nearly all the highly stressed rotating parts (disks, fan blades, main shafts, etc) have a cyclic life limit since catastrophic failure of these is not tolerated. Upon reaching this limit they must be removed from service. These life limits are hard regulatory limits. Other limits can be varied by operators based on their experience.eg. a Middle Eastern operator might find it necessary to perform tasks more frequently or have a reduced on-wing life because of the high temperatures they operate in and sand/dust ingestion whereas a temperate climate operator may be able to extend the intervals and on-wing life.

I flew once a 737 that had a CFM56 installed which was on the wing for more than 30.000 hours, it ended up reaching over 40.000 hours on the wing with an average sector length of 2 hours. However at the end it was prone to hot starts especially in summer with a tailwind during engine start.

CV 880

Many thanks for your most informative response.

Dent

Thanks also for your interesting experience

:)

Not always that simple unfotunately
 

Life on wing tends to be cycle driven rather than hours. CFM is quite critical on thrust rating as to how long it stays on but V2500 isn't (ie not thrust dependent). This is the the plan but performance tends to override this and of course condition of the engine from boroscopes often due to fuel burn figures will dictate an early removal

I'll get me coat....

Engines can be almost infinately overhauled. Parts repaired or replaced. Of course at some time you reach a point where there is nothing original about the engine. By that time the aircraft type is usually in some desert parking lot.