Airworthiness Directive · Amendment 39-15547 · Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes
Boeing Model 737-600, -700, -700C, -800, and -900 Series Airplanes
Superseded. A later AD replaced this one: AD 2017-19-26. Comply with the one in force.
This AD applies to Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes, certificated in any category; as identified in Boeing Special Attention Service Bulletin 737-53-1232, dated April 2, 2007.
We are adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. This AD requires various repetitive inspections to detect cracks along the chemically milled steps of the fuselage skin or missing or loose fasteners in the area of the preventative modification or repairs, replacement of the time-limited repair with the permanent repair if applicable, and applicable corrective actions if necessary, which would end certain repetitive inspections. This AD results from a fatigue test that revealed numerous cracks in the upper skin panel at the chemically milled step above the lap joint. We are issuing this AD to detect and correct such fatigue-related cracks, which could result in the crack tips continuing to turn and grow to the point where the skin bay flaps open, causing decompression of the airplane.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
The term “service bulletin,” as used in this AD, means Boeing Special Attention Service Bulletin 737-53-1232, dated April 2, 2007.
At the applicable compliance times listed in Tables 1, 2, and 3 of paragraph 1.E., “Compliance,” of the service bulletin, or within the time specified in paragraph (g)(1) or (g)(2) of this AD, as applicable, whichever occurs later, and thereafter at the applicable repeat intervals listed in Tables 1, 2, and 3: Do the applicable inspections and replacement by accomplishing all the applicable actions specified in the Accomplishment Instructions of the service bulletin.
(1) For airplanes specified in Tables 1 and 2 of paragraph 1.E., “Compliance,” of the service bulletin: Do the applicable initial inspection required by paragraph (g) of this AD within 36 months after the effective date of this AD.
(2) For airplanes specified in Table 3 of paragraph 1.E., “Compliance,” of the service bulletin: Do the applicable initial inspection and replacement required by paragraph (g) of this AD within 24 months after the effective date of this AD.
If any crack or loose or missing fastener is found during any applicable inspection required by paragraph (g) of this AD, before further flight, do the applicable corrective action in accordance with the service bulletin; except, where the service bulletin specifies to contact Boeing for appropriate action, before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (l) of this AD.
(i) For airplanes on which the preventative modification specified in the service bulletin has not been installed: Accomplishing the preventative modification, time-limited repair, or permanent repair in accordance with the service bulletin ends the applicable repetitive external detailed inspections required by paragraph (g) of this AD.
For any airplane subject to the requirements of paragraph (g) of this AD: Inspections done at the compliance times specified in Table 1 of paragraph 1.E., “Compliance,” of the service bulletin are not required in areas that are spanned by an FAA-approved repair that has a minimum of 3 rows of fasteners above and below the chemically milled step. Post-repair supplemental inspections are to be done at the times specified in Table 2 of paragraph 1.E., “Compliance,” of the service bulletin.
(k) For any airplane that has an external doubler covering the chemically milled step, but the doubler does not span the step by a minimum of 3 rows of fasteners above and below the chemically milled step: Instead of requesting approval for an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (l) of this AD, one method of compliance with the inspection requirement of paragraph (g) of this AD is to inspect all chemically milled steps covered by the repair using non-destructive test (NDT) methods in accordance with the Boeing 737 NDT Manual, Part 6, Subject 53-30-20. These repairs are to be considered time-limited and are subject to the post-repair supplemental inspections and replacement at the times specified in Table 3 of paragraph 1.E., “Compliance,” of the service bulletin.
