Airworthiness Directive · Amendment 39-17532 · Doors
The Boeing Company Airplanes
(1) 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 Alert Service Bulletin 737-52A1167, dated December 1, 2011.
(2) Installation of Supplemental Type Certificate (STC) ST00830SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/408E012E008616A7862578880060456C?OpenDocument&Highlight=st00830se) does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST00830SE 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 adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This AD was prompted by a report of an inboard main landing gear (MLG) door assembly departure due to premature fatigue cracking in the inboard MLG door hinge fittings. This AD requires repetitive inspections for cracking of the inboard MLG door hinge fittings; and replacement or modification of cracked fittings. This AD also provides an option to remove the affected MLG door. We are issuing this AD to detect and correct fatigue cracking in the inboard MLG door hinge fittings, which could result in loss of the MLG door assembly from the airplane, and the MLG door assembly could impact the flight control surfaces and result in reduced controllability of the airplane.
Except as provided by paragraph (i) of this AD, at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-52A1167, dated December 1, 2011, do either a detailed or surface high frequency eddy current (HFEC) inspection for cracking of the left- and right-side inboard MLG door hinge fittings, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-52A1167, dated December 1, 2011.
(1) If no cracking is found, at the times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-52A1167, dated December 1, 2011, do the actions specified in either paragraph (g)(1)(i) or (g)(1)(ii) of this AD, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-52A1167, dated December 1, 2011.
(i) Repeat either a detailed or a surface HFEC inspection for cracking of the left- and right-side inboard MLG door hinge fittings.
(ii) Modify the hinge fittings on the inboard MLG doors by installing P/N 113A8341-9 and 113A8341-10, in accordance with Part 3 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-52A1167, dated December 1, 2011. Doing the modification specified in this paragraph terminates the inspection requirements for only the door on which new fittings are installed.
(2) If any cracking is found, before further flight, do the actions specified in either paragraph (g)(2)(i) or (g)(2)(ii) of this AD.
(i) Modify the hinge fittings on all affected inboard MLG doors by installing P/N 113A8341-9 and 113A8341-10, in accordance with Part 3 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-52A1167, dated December 1, 2011. Doing the modification specified in this paragraph terminates the inspection requirements for only the door on which new fittings are installed.
(ii) Remove the affected MLG door, using a method approved in accordance with the procedures specified in paragraph (j) of this AD. For airplanes on which this door is reinstalled, before further flight, accomplish the actions specified in either paragraph (h)(1) or (h)(2) of this AD on the reinstalled door.
Note 1 to paragraph (g)(2)(ii) of this AD: Guidance for removing the door can be found in Section 32-10 of Appendix CDL, Configuration Deviation List, Model 737-100/200/300/400/500/600/700/800/900/900 ER Series, to the Boeing 737-700 Airplane Flight Manual Document D631A001.
(1) Installing new MLG door hinge fittings having P/N 113A8341-9 and 113A8341-10, terminates the inspection requirements of this AD for only the doors on which new fittings are installed.
(2) Installing new MLG door hinge fittings having P/N 113A8341-1 and 113A8341-2, is acceptable for compliance with the modification specified in paragraphs (g)(1)(ii) and (g)(2)(i) of this AD, provided the inspections (both the initial and the repetitive inspections) required by paragraph (g) of this AD are done within the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-52A1167, dated December 1, 2011. Installation of the MLG door hinge fittings having P/N 113A8341-1 and 113A8341-2, as applicable, must be done using a method approved in accordance with the procedures specified in paragraph (j) of this AD. Accomplishing the requirements of this paragraph does not terminate the inspection requirements of paragraph (g) of this AD.
Where Boeing Alert Service Bulletin 737-52A1167, dated December 1, 2011, specifies a compliance time “after the original issue date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.
