Airworthiness Directive · Amendment 39-17530 · Wings
The Boeing Company Airplanes
(1) This AD applies to all The Boeing Company Model 737-300, -400, and -500 series airplanes, certificated in any category.
(2) Installation of Supplemental Type Certificate (STC) ST01219SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/2C6E3DBDDD36F91C862576A4005D64E2?OpenDocument&Highlight=st01219se) does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01219SE is installed, a “change in product” alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17.
We are superseding airworthiness directive (AD) 2008-06-29, which applied to all The Boeing Company Model 737-300, -400, and -500 series airplanes. AD 2008-06-29 required repetitive inspections of the downstop assemblies on the main tracks of the No. 2, 3, 4, and No. 5 slats and the inboard track of the No. 1 and 6 slats to verify if any parts are missing, damaged, or in the wrong order; other specified actions; and related investigative and corrective actions if necessary. This new AD retains these requirements and adds an inspection of the slat can interior for foreign object debris (FOD), and removal of any FOD found; modification of the slat track hardware; an inspection for FOD and for damage to the interior surface of the slat cans; and related investigative and corrective actions, if necessary. This AD was prompted by development of a modification by the manufacturer, which, when installed, would terminate the repetitive inspections. We are issuing this AD to prevent loose or missing parts in the main slat track downstop assemblies, which could puncture the slat track housing and result in a fuel leak and consequent fire.
This paragraph restates the requirements of paragraph (f) of AD 2008-06-29, Amendment 39-15441 (73 FR 15397, March 24, 2008), with revised service information. At the applicable times specified in Table 1 of paragraph 1.E. of Boeing Alert Service Bulletin 737-57A1301, dated February 5, 2008; or Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011; except as provided by paragraph (g)(1) of this AD: Do a detailed inspection or borescope inspection of the downstop assemblies on the main tracks of the No. 2, 3, 4, and 5 slats and the inboard track of the No. 1 and 6 slats to verify if any parts are missing, damaged, or installed in the wrong order; and do all the other specified, related investigative, and corrective actions as applicable; by accomplishing all of the applicable actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1301, dated February 5, 2008; or Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011; except as provided by paragraphs (g)(2) and (g)(3) of this AD. Repeat the inspection thereafter at the applicable times specified in Table 1 of paragraph 1.E. of Boeing Alert Service Bulletin 737-57A1301, dated February 5, 2008; or Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011. Do all applicable related investigative and corrective actions before further flight. As of the effective date of this AD, only Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011, may be used to accomplish the actions required by this paragraph.
(1) Where Boeing Alert Service Bulletin 737-57A1301, dated February 5, 2008, or Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011, specifies counting the compliance time from “the date on the service bulletin,” this AD requires counting the compliance time from April 8, 2008 (the effective date of AD 2008-06-29, Amendment 39-15441 (73 FR 15397, March 24, 2008)).
(2) For airplanes on which any downstop assembly part is missing or damaged, a borescope inspection of the inside of the slat track housing for loose parts and damage to the wall of the slat track housing may be accomplished in lieu of the detailed inspection of the inside of the slat track housing that is specified in Boeing Alert Service Bulletin 737-57A1301, dated February 5, 2008; or Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011. As of the effective date of this AD, only Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011, may be used to do the actions specified in this paragraph.
(3) If any damaged slat track housing is found during any inspection required by paragraph (g) of this AD: Before further flight, repair in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011; replace the slat can with a new slat can having the same part number, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011; or repair the slat can using a method approved in accordance with the procedures specified in paragraph (k) of this AD.
Within 24 months after the effective date of this AD, do a one-time detailed inspection of the slat can interior to detect FOD, in accordance with Part III of the Accomplishment Instructions of Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011. If any FOD is found, before further flight, remove it, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011.
Within 72 months or 15,000 flight cycles, whichever occurs first, after the effective date of this AD: Modify the slat track hardware by installing new downstop assembly hardware, and do a detailed inspection for FOD and a one-time inspection for damage to the interior surface of the slat can for the inboard and outboard tracks of slats 2 through 5, and the inboard slats of tracks 1 and 6; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Service Bulletin 737-57A1301, Revision 3, dated August 11, 2011. Do all applicable related investigative and corrective actions before further flight. Accomplishment of the actions required by this paragraph terminates the inspections required by paragraphs (g) and (h) of this AD.
