Airworthiness Directive · Amendment 39-17066 · Wings
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 777-200, -200LR, -300, -300ER, and 777F series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 777-57A0090, dated August 24, 2011.
We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 777 airplanes. This AD was prompted by four reports of retaining cross bolt hardware not fully engaged into the fuse pins of the forward trunnion lower housing of the main landing gear (MLG), which could result in an incorrect MLG emergency landing break-away sequence. This AD requires a detailed inspection of the fuse pin cross bolts and fuse pins of the left and right MLG forward trunnion lower housing to verify that the cross bolts are correctly installed and that there are no missing fuse pins, and replacement of the fuse pins if necessary. We are issuing this AD to prevent an incorrect emergency landing MLG break-away sequence, which could result in puncturing of the wing box and consequent fuel leaks and an airplane fire. Failure of the fuse pins could also result in a possible landing gear collapse causing a runway excursion during take-off or landing.
Within 1,125 days after the effective date of this AD, perform a detailed inspection of the fuse pin cross bolts and fuse pins of the left and right MLG forward trunnion lower housing to verify that the cross bolts are installed correctly and that there are no missing fuse pins, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 777-57A0090, dated August 24, 2011. If any cross bolt of the MLG forward trunnion lower housing is not installed correctly, or if any fuse pin of the MLG forward trunnion lower housing is missing: Before further flight, replace all fuse pins in the MLG forward trunnion upper and lower housing on the side, or sides, of the airplane where the missing or incorrectly installed fuse pin/pins were discovered, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 777-57A0090, dated August 24, 2011, except step 1 in Part 2 of paragraph 3.B of the Accomplishment Instructions of Boeing Alert Service Bulletin 777-57A0090, dated August 24, 2011, is not considered regulatory for the purposes of this AD.
The aircraft, engines and makers this AD names, by the model designations in its text. A model listed here may still be outside the AD's serial ranges.
Aircraft
