TBO Question

[Idle Thrust]

In a recent discussion the subject of "Time between overhauls" came up as it pertains to modern jet (turbofan) engines.

My knowledge is pretty thin but I believe current monitoring equipment allows leaving the engine on the wing until the monitored parameters reach limits that require removal as opposed to the old "hard hour number" for overhauls based on past performance of the engine type and operating regime.

If this is correct can anyone provide representative numbers for the modern engines as to how long they typically operate before being removed? I recall an item a few years ago about a very high time engine (GE I think) that was up into the 20 or 30K range.

Thanks in advance.

[oldebloke]

Heard of extreme cases ,but 20000hrs seem to be achieved regularly..AirCanada had an engine on the 747 for 5 years,without touching(apart from the fluid levels of course..:ok:

[barit1]

...can anyone provide representative numbers for the modern engines as to how long they typically operate before being removed?
Today's issue of AW&ST (p.46) states "The GE90 is is now averaging 3,200 cycles before requiring maintenance--the equivalent of 20,000 hr. on wing" per GE.

Operating cycles -- startup, TO, climb, cruise, descent/landing, R/T -- are a better measure of wear & tear than sheer flight hours. The longhaul operator will obviously accumulate more hours.

A long time ago the DC-3 operator I worked for had a devil of a time getting R-1820's to run 1200 hrs!