Sources: 787 fatigue airframe passes 10,000 cycles

Boeing 787-8 ZY998

Boeing’s 787 fatigue test airframe has passed the critical 10,000 cycle milestone, solidifying a regulatory requirement to maintain ahead of the fleet leader in simulated takeoffs and landings, say program sources. 
The airframe, dubbed ZY998, first began its fatigue trials in September 2010, parked behind the Everett factory in a custom test fixture designed to simulate the normal stresses on an aircraft during flight. 
Each cycle, representing one takeoff and one landing, includes flexing of the various structures, as well as repeated pressurizations expanding and contracting the aircraft’s composite primary structure fuselage.
The airframer expects to certify the 787 for 44,000 cycles in its lifetime, but is required to double that margin during the testing, which must remain 10,000 cycles ahead of the flying fleet leader. Boeing will push ZY998 to as many as 165,000 over the next three years to determine the long-term structural life of the 787.

4 Responses to Sources: 787 fatigue airframe passes 10,000 cycles

  1. Maarten Schenk May 27, 2011 at 5:24 am #

    Testing the comments

  2. JoeCanuck May 27, 2011 at 5:47 am #

    What is the average duration of 1 cycle? Is a cycle a primarily pressurization event or are the wings flexed as well?

    Thank you.

  3. AirShowFan May 27, 2011 at 11:55 am #

    Actually, as per FAR 25.517, the fatigue-test airplane’s “flights” must remain ahead of the fleet leader by a factor of two, not just 10,000:

    http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgFAR.nsf/0/008C7B7F5E6293F3862577DE005229E7?OpenDocument

    “No airplane may be operated beyond a number of cycles equal to 1/2 the number of cycles accumulated on the fatigue test article”.

    And Canuck; As you can read here…

    http://www.boeing.com/Features/2010/09/bca_fatigue_testing_09_13_10.html

    http://tinyurl.com/AvWeek787Fatigue

    … there is pressurization, loading of the wings and tail fin and control surfaces… Lots and lots of actuators (over 100, according to the articles above) pushing lots and lots of places on the airplane to simulate flight loads as precisely as possible.

    As for how long a cycle is… That Boeing article say they want to do 100,000 in 3 years. Do the math ;]

  4. Jeff in SHerwood May 31, 2011 at 11:38 am #

    Here’s the math…

    100,000 Total Cycles
    10,000 Already Done
    90,000 Remaining Cycles
    365 Days/Year
    3 Years
    1096 Days (Leap year included)
    82.11678832 Cycles/Day
    3.421532847 Cycles/Hour
    17.536 Minutes/Cycle

    and for 165,000 (in 3 years? Not sure where that number came from…)
    165,000 Total Cycles
    10,000 Already Done
    155,000 Remaining Cycles
    365 Days/Year
    3 Years
    1096 Days (Leap year included)
    141.4233577 Cycles/Day
    5.892639903 Cycles/Hour
    10.18219355 Minutes/Cycle

    (OK, you can take out your electronic devices. Now, put it away!) I know there is more that I am missing on this, but the math sure is fun to do!

    Jeff