Airworthiness Directive · Amendment 39-17234 · Wings
The Boeing Company Airplanes
This AD applies to The Boeing Company Model MD-90-30 airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin MD90-57A030, dated February 14, 2012.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model MD-90-30 airplanes. This AD was prompted by reports of fatigue cracks found in Stringer 11 at the outboard flap, inboard drive hinge at Station Xrs=164.000. This AD requires repetitive inspections for cracks in Stringer 11, and a splice repair if necessary; and repetitive post-repair inspections, and repair if necessary. We are issuing this AD to detect and correct such cracking, which could result in the wing structure not supporting the limit load condition, which could lead to loss of the structural integrity of the wing.
Before the accumulation of 14,000 total flight cycles, or within 9,470 flight cycles after the effective date of this AD: Whichever occurs later, do an in-tank eddy current high frequency (ETHF) inspection for cracks in Stringer 11 at the outboard flap, inboard drive hinge at Station Xrs=164.000 of the left and right wings, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-57A030, dated February 14, 2012. If no cracking is found, repeat the inspection thereafter at intervals not to exceed 31,000 flight cycles.
If any cracking is found during any inspection required by paragraph (g) of this AD: Before further flight, do a splice repair, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-57A030, dated February 14, 2012.
Within 42,000 flight cycles after doing the splice repair specified in paragraph (h) of this AD: Do an ETHF inspection for cracks in Stringer 11 at the outboard flap, inboard drive hinge at Station Xrs=164.000, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin MD90-57A030, dated February 14, 2012. Repeat the inspection thereafter at intervals not to exceed 31,000 flight cycles. If any crack is found: Before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (j) of this AD.
