Airworthiness Directive · Amendment 39-15892 · Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes
Boeing Model 737-100, -200, -200C, -300, -400, and -500 Series Airplanes
This AD applies to Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 737-53A1269, dated May 17, 2007.
We are adopting a new airworthiness directive (AD) for certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD requires repetitive detailed and high frequency eddy current inspections to detect cracks of the backup intercostals and the upper sill of the forward airstair doorway, and applicable corrective actions. This AD also provides for an optional terminating action, which would eliminate the need for repetitive inspections. This AD results from a report indicating that cracks were found in the backup intercostals and upper sill web of the forward airstair doorway. We are issuing this AD to detect and correct fatigue cracking of the backup intercostals and upper sill web of the forward airstair doorway, which could result in a rapid loss of cabin pressure.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
At the applicable compliance times and repeat intervals listed in the tables of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1269, dated May 17, 2007 (hereafter “the service bulletin”), except as provided by paragraphs (f)(1), (f)(2), and (f)(3) of this AD: Do repetitive detailed and high frequency eddy current inspections to detect cracks of the backup intercostals and the upper sill of the forward airstair doorway, and applicable corrective actions by accomplishing all the applicable actions specified in the Accomplishment Instructions of the service bulletin. Do the applicable corrective actions before further flight.
(1) Where the service bulletin specifies a compliance time from the release date of the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.
(2) Where the columns identified as “Airplane Flight Cycles” in the tables of the service bulletin specify less than 45,000 total flight cycles for certain actions, this AD affects airplanes having less than or equal to 45,000 total flight cycles.
(3) Where the columns identified as “Repeat Interval” in the tables of the service bulletin specify an interval of 4,500 flight cycles for all conditions, this AD requires repetitive inspections only if no crack is found during any inspection required by paragraph (f) of this AD.
Accomplishing the backup intercostal repair/preventative modification and/or the upper door sill web repair, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-53A1269, dated May 17, 2007, terminates all the corresponding repetitive inspection requirements of paragraph (f) of this AD.
