5 ms·

It might make sense for a small airline to order a spare plane, just in case it's needed at some point. Especially if that plane model matches their flight pro

by smackfu 11y ago

It might make sense for a small airline to order a spare plane, just in case it's needed at some point. Especially if that plane model matches their flight profile really well, but also had a small production run so it would be difficult to lease a replacement. And if Boing really wants to get sales of the plane to make it look like a success, there might be a sweet price for that extra plane. And since plane age is measured in takeoff/landing cycles, a plane that is sitting in storage isn't really aging.

notahacker 11y ago
It's not strictly true that aircraft age is measured in takeoff and landing cycles and YoY depreciation is pretty huge for new aircraft even holding condition constant, but I'd agree that it might make commercial sense to keep a >10 year old 717 on standby. More likely to be short term fluctuations in demand or a short term airworthiness issue than any intent to have a "spare" aircraft though.
phillc73 11y ago
Aeroplane age is generally measured in total hours flown. Turbine engine life is measure in a combination of cycles and operating hours. A piston engine aeroplane has nothing measured in takeoff/landing cycles, although it is good practice to record this information on the Maintenance Release.
- WalterBright 11y ago
  Take/off landing cycles affect jets more because they fly at higher altitudes, and you get the pressurization/depressurization fatigue stress cycles.
- engi_nerd 11y ago
  There's no one measure for aircraft age. Flight hours, takeoff/landing cycles, and pressurization cycles are all measures that tell you different things. The program I work on tracks flight hours, engine operating hours, and takeoffs/landings.
  - hga 11y ago
    Many of us might remember the miraculous Aloha Airlines Flight 243, a 737 bought new by the airline in 1969, which in 1988 after 35,496 flight hours, but over 89,680 takeoff and landing cycles, lost 1/3 of its top fuselage and one flight attendant (it did a lot of short flights between the islands see https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243 https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243). Per the Conclusion of the Wikipedia article: Under current FAA regulations for the Boeing 737 (line number 291 and prior) established in the 2010s, this airframe would have had to be permanently withdrawn from service after 34,000 flight cycles or 34,000 hours, whichever came first (for production number 292 and higher, it was increased to 75,000 flight cycles and 100,000 hours). The nearly 90,000 flight cycles exceeded the design limit of the 737-100/200 under either construction model.
    - engi_nerd 11y ago
      Yes, this was the example in my mind, thank you for posting about it. Flight hours weren't informative enough in the case of this aircraft because it spent its time making short hops involving lots of pressurization cycles.

by smackfu 11y ago

notahacker 11y ago

It's not strictly true that aircraft age is measured in takeoff and landing cycles and YoY depreciation is pretty huge for new aircraft even holding condition constant, but I'd agree that it might make commercial sense to keep a >10 year old 717 on standby. More likely to be short term fluctuations in demand or a short term airworthiness issue than any intent to have a "spare" aircraft though.

phillc73 11y ago

Aeroplane age is generally measured in total hours flown. Turbine engine life is measure in a combination of cycles and operating hours. A piston engine aeroplane has nothing measured in takeoff/landing cycles, although it is good practice to record this information on the Maintenance Release.

WalterBright 11y ago
Take/off landing cycles affect jets more because they fly at higher altitudes, and you get the pressurization/depressurization fatigue stress cycles.
engi_nerd 11y ago
There's no one measure for aircraft age. Flight hours, takeoff/landing cycles, and pressurization cycles are all measures that tell you different things. The program I work on tracks flight hours, engine operating hours, and takeoffs/landings.
- hga 11y ago
  Many of us might remember the miraculous Aloha Airlines Flight 243, a 737 bought new by the airline in 1969, which in 1988 after 35,496 flight hours, but over 89,680 takeoff and landing cycles, lost 1/3 of its top fuselage and one flight attendant (it did a lot of short flights between the islands see https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243 https://en.wikipedia.org/wiki/Aloha_Airlines_Flight_243). Per the Conclusion of the Wikipedia article: Under current FAA regulations for the Boeing 737 (line number 291 and prior) established in the 2010s, this airframe would have had to be permanently withdrawn from service after 34,000 flight cycles or 34,000 hours, whichever came first (for production number 292 and higher, it was increased to 75,000 flight cycles and 100,000 hours). The nearly 90,000 flight cycles exceeded the design limit of the 737-100/200 under either construction model.
  - engi_nerd 11y ago
    Yes, this was the example in my mind, thank you for posting about it. Flight hours weren't informative enough in the case of this aircraft because it spent its time making short hops involving lots of pressurization cycles.