CodyKDiamond From Canada, joined Nov 2006, 537 posts, RR: 1 Posted (5 years 7 months 2 weeks 5 days 17 hours ago) and read 5395 times:
Sad news today everyone. Air Lib DC-10 N956PT will be scrapped shortly. Engine number 1 only has 5 cycles left while the number 2 and 3 will be sold. It is doing runups tonight. It will be scrapped, however, there is a small chance a movie company may save it. I went onboard today and got a few safety cards. Most of the seating, insulation, and cabin panels are removed however the flightdeck is in great condition. Remember, this a/c was Finnair's first DC-10-OH-LHA. Biting the dust alongside 956 will be Arrow's DC-8 (N661AV) and DC-10-40 (N140WE). At least I got on them all. I will post photos later. This a/c has been at OPF for four years, going on five.
CF6PPE From United States of America, joined Mar 2006, 344 posts, RR: 0
Reply 2, posted (5 years 7 months 2 weeks 4 days 9 hours ago) and read 4792 times:
Quoting BSU747 (Reply 1): Can somebody explain how many cycles an engine is supposed to have, and also does this take into account short and long flights in terms of hours.
Flight cycles built into an engine are dependent upon the operators needs and flight profiles. For instance if an engine is reassembled with a minimum of 2,500 cycles, and is operated on an average of two hours per flight cycle, the engine has a Life Limited Part life of approx. 5,000 hours, however that same engine operated on an average of five hour per flight cycle is good for approx. 12,500 hours. Usually operators with longer flight profiles don't build in as many cycles as do short cycle operators.
The comment about only 5 cycles remaining probably applies to only one rotating part. The remaining rotating parts may or may not be close; it depends on the selection of parts available at the time that the engine was reassembled. I've seen all kinds of combinations of rotating parts lives in engines. Some engine repair shops are better at matching the Life Limited Parts than others (no offense intended).
For transport category aircraft, a flight cycle is generally defined as a take-off and landing. For powerplants, this usually includes the power excursions between take-off and landing but not usually the power excursions due to touch and go landing - take-offs (but depends on engine manufacturer).
Most all of the N1/N2/N3 rotating parts have life cycle limits which are specified in the time limits section of the applicable engine type shop manual. These time limits are established by finite part analysis and verified by evaluation/inspection of operational and test samples for each rotating part and rotating part assembly.
The big thing to remember here is that some parts have life limits that are high (30,000hours/20,000 cycles) while others are much lower (maybe a few thousand cycles). When an engine is input into a shop, evaluation of the cycles remaining on the rotating parts is done to decide which parts can be reused due to having sufficient remaining cycles.
Hopefully, this answered your question.
One last thought, at aircraft return, many lease contracts require a minimum of five cycles remaining so that the aircraft can be ferried without needing an engine R&R.
BSU747 From United Kingdom, joined Jul 2004, 172 posts, RR: 0
Reply 4, posted (5 years 7 months 2 weeks 3 days 9 hours ago) and read 4362 times:
Many thanks for your detailed reply CF6PPE, it has made it a bit easier to understand how the protocol regarding engine lifespan is, always curious as to how engines were maintained in regards to hours/cycles flown.
Flying may not be all plain sailing, but the fun of it is worth the price.