Airworthiness Directive · Amendment 39-16629 · Wings
The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER Series Airplanes
This AD applies to The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes, certificated in any category, as identified in Boeing Service Bulletin 737-57A1302, Revision 1, dated October 18, 2010.
The FAA is superseding an existing airworthiness directive (AD), which applies to all Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. That AD currently requires repetitive detailed inspections of the slat track downstop assemblies to verify that proper hardware is installed, one-time torquing of the nut and bolt, and corrective actions if necessary. This new AD also requires replacing the hardware of the downstop assembly with new hardware of the downstop assembly, doing a detailed inspection or a borescope inspection of the slat cans on each wing and the lower rail of the slat main tracks for debris, replacing the bolts of the aft side guide with new bolts, and removing any debris found in the slat can. This AD also removes airplanes from the applicability. This AD results from reports of parts coming off the main slat track downstop assemblies. We are issuing this AD to prevent loose or missing parts from the main slat track downstop assemblies from falling into the slat can and causing a puncture, which could result in a fuel leak and consequent fire.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Note 1: Paragraph (g) of this AD merely restates the requirements of paragraph (f)(1) of emergency AD 2007-18-51 (which was superseded by AD 2007-18-52). As allowed by the phrase, “unless the actions have already been done,” if the applicable initial inspections required by paragraph (f)(1) of emergency AD 2007-18-51 have already been done, this AD does not require that those inspections be repeated until the repetitive interval of 3,000 flight cycles.
Within 10 days after September 26, 2007 (the effective date of AD 2007-18-52): Do a detailed inspection or a borescope inspection of each main slat track downstop assembly to verify proper installation of the slat track hardware (i.e., the bolt, washers, downstops, stop location, and nut shown in Figure 1 of Boeing Service Letter 737-SL-57-084-B, dated July 10, 2007, and in this AD). Proper installation of the sleeve need not be confirmed, and the stop location part may be installed on either the inboard or the outboard side of the slat track. If any part is missing or is installed improperly, before further flight, install a new or serviceable part using a method approved in accordance with the procedures specified in paragraph (j) of this AD; and do a detailed inspection of the inside of the slat can for foreign object debris (FOD) and damage. Before further flight, remove any FOD found and repair any damage found using a method approved in accordance with the procedures specified in paragraph (j) of this AD. Verify proper installation; install a new or serviceable part; and inspect for damage and FOD, and remove FOD and repair damage; in accordance with a method by approved by the Manager, Seattle Aircraft Certification Office, FAA; or in accordance with Boeing Multi Operator Message Number 1-523812011-1, issued August 25, 2007, or 1-527463441-1, issued August 28, 2007. Repeat the actions required by paragraph (g) of this AD thereafter at intervals not to exceed 3,000 flight cycles.
Note 2: Paragraph (h) of this AD merely restates the requirements of paragraph (f)(2) of emergency AD 2007-18-51. As allowed by the phrase, “unless the actions have already been done,” if the torque application required by paragraph (f)(2) of AD emergency 2007-18-51 has already been done, this AD does not require that the torque application be repeated.
Within 24 days after receipt of emergency AD 2007-18-51: Apply a torque between 50 to 80 inch-pounds to the nut. The bolt head must be held with the torque applied to the nut.
Note 3: For the purposes of this AD, a detailed inspection is: “An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.”
(i) Within 36 months after the effective date of this AD: Replace the hardware of the down stop assembly with new hardware, do a detailed inspection or a borescope inspection of the slat cans on each wing and the lower rail of the slat main tracks for debris, and replace the bolts of the aft side guide with new bolts, in accordance with Part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1302, dated December 15, 2008; or Boeing Service Bulletin 737-57A1302, Revision 1, dated October 18, 2010; except, where Boeing Alert Service Bulletin 737-57A1302, dated December 15, 2008, and Boeing Service Bulletin 737-57A1302, Revision 1, dated October 18, 2010, specify to replace the slat main track or to contact Boeing for further repair instructions if the hole diameter is greater than 0.5005 inch, before further flight, replace the slat main track in accordance with Boeing Alert Service Bulletin 737-57A1302, dated December 15, 2008, Boeing Service Bulletin 737-57A1302, Revision 1, dated October 18, 2010, or repair using a method approved in accordance with the procedures specified in paragraph (j) of this AD. If debris is found during any inspection required by this AD, before further flight, remove the debris in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1302, dated December 15, 2008; or Boeing Service Bulletin 737-57A1302, Revision 1, dated October 18, 2010. Doing the actions required by paragraph (i) of this AD terminates the actions required by paragraphs (g) and (h) of this AD. Installation of stainless steel lockwire having part number (P/N) MS20995C32 is acceptable for compliance in lieu of lockwire P/N MS20995NC32, as specified in Boeing Alert Service Bulletin 737-57A1302, dated December 15, 2008, for this AD.
