Aircraft life

[eight]

Does anyone know how many flights an aircraft (B777) is designed to fly during its life?

[eight]

I haven't found anything completely conclusive but 75000 pressurisation cycles seems to be the average. Can anyone confirm this?

[Jetset320]

Not an answer to your question exactly, but the first 777 is being presently scrapped in Brasil. It's an ex BA machine which was on lease to Varig.

[barit1]

Remember that aircraft on short-haul routes accumulate more cycles but fewer hours, in general, in their lifetime.

And in wear and tear, cycles count more than hours.

[seacue]

Short-haul planes are designed for more cycles than long-haul planes.

A turboprop and not pressurized, but Winair retired a DHC Twin Otter after approximately 131,000 cycles. Winair's typical flight duration is about 15-20 minutes.

Isn't some passenger jet up to about half that number? Major, major work can extend life in some cases.

[vapilot2004]

The Boeing 777 has a DSO (design service objective) of 40,000 cycles.

However, the 777 has an in-service test fatigue cycle rating of 120,000 when using modified maintenance procedures designed for extended use.

[barit1]

The 732 in the 1988 Aloha accident (http://amelia.db.erau.edu/reports/ntsb/aar/AAR89-03.pdf) had 89,680 cycles. At the time, it was the second-highest-cycle 737 in the world.

[eight]

Thanks for the replies.

[archae86]

This posted Boeing document is on corrosion, but asserts that the general design objective is 20 years service life--implying that the cycle objective is derived from that via assumptions regarding route structure and utilization.

It gives design cycle and flight hour objectives by model for many Boeing and (former) Douglas jet transport designs, with the cycle objective ranging from a low of 20,000 for the 707, 747, and MD-11 to a high of 60,000 for the MD-90.

It also observes that many flying aircraft have exceeded their service design life objectives.
service life table (http://www.boeing.com/commercial/aeromagazine/aero_07/corrosn_sb_table01.html)

[eight]

Thanks for that link, it confirms data I found elsewhere. Very helpful, especially as it is a Boeing source.

[Old Smokey]

It's interesting to note from the Boeing table that the DC9 is "King of the hill", far above the rest, with the B727 not a bad second place holder.

The highest time DC9 has exceeded 120,000 hours at last count, possibly somewhat higher by now.

It was said to me my a Douglas sales rep at the time of a contemplated purchase, that the worst favour Douglas ever did for themselves was to build such long life aircraft. Better to follow the Boeing "trash 'em and buy a new one" policy.

Now that the DC9 family flies under the Boeing flag as the B717, I privately wonder (cynically) what Boeing have done to reduce the B717 life cycle.:E

Regards,

Old Smokey (who flew a lot of DC9s, but now puts his butt and trust in Boeing)