Airworthiness Directive · Amendment 39-16519 · Wings
The Boeing Company Model 737-900ER Series Airplanes
This AD applies to The Boeing Company Model 737-900ER series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 737-57A1308, Revision 1, dated October 1, 2009.
We are adopting a new airworthiness directive (AD) for the products listed above. This AD requires doing a one-time general visual inspection for a keyway in two fuel tank access door cutouts, and related investigative and corrective actions if necessary. This AD was prompted by reports of cracks emanating from the keyway of the fuel tank access hole. We are issuing this AD to detect and correct such cracking, which could result in the loss of the lower wing skin load path and consequent structural failure of the wing.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Before the accumulation of 7,500 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, do a one-time general visual inspection for a keyway in the fuel tank access door cutouts 531BB and 631BB, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1308, Revision 1, dated October 1, 2009 (“the service bulletin”).
Note 1: For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”
(1) If both access door cutouts do not have a keyway, no further action is required by this AD.
(2) If any access door has a keyway, before the accumulation of 7,500 total flight cycles, or within 1,000 flight cycles after the effective date of this AD, whichever occurs later, do a high frequency eddy current (HFEC) inspection for cracking of the keyway, in accordance with the Accomplishment Instructions of the service bulletin.
(i) If no cracking is found during the HFEC inspection, before further flight, modify the profile of the keyway of the fuel tank access door cutout, in accordance with the Accomplishment Instructions of the service bulletin.
(ii) If any cracking is found and the crack is 0.030 inch or less in length, before further flight repair the keyway, in accordance with the Accomplishment Instructions of the service bulletin.
(iii) If any cracking is found and the crack is greater than 0.030 inch in length, before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (h) 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
