Airworthiness Directive · Amendment 39-18791 · Stabilizers
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/ebd1cec7b301293e86257cb30045557a/$FILE/ST01219SE.pdf) 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 adopting a new airworthiness directive (AD) for all The Boeing Company Model 737-300, -400, and -500 series airplanes. This AD was prompted by reports of intergranular cracks on the front spar chord lugs of the outboard horizontal stabilizer. This AD requires repetitive inspections of the front spar chord lugs and lug bores of the horizontal stabilizer, and repair if necessary. We are issuing this AD to address the unsafe condition on these products.
Within 27 months after the effective date of this AD: Do the actions required by paragraphs (g)(1) and (g)(2) of this AD, and do all applicable repairs, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-55A1092, dated August 7, 2015, except as required by paragraph (h) of this AD. Do all applicable repairs before further flight. Repeat the inspections specified in paragraphs (g)(1) and (g)(2) of this AD thereafter at the applicable intervals specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-55A1092, dated August 7, 2015.
(1) Do a detailed inspection for corrosion and an ultrasonic inspection for cracking of the front spar chord lugs of the left and right horizontal stabilizers.
(2) Do a detailed inspection for corrosion of the lug bores of the front spar chord of the left and right horizontal stabilizers.
Where Boeing Alert Service Bulletin 737-55A1092, dated August 7, 2015, specifies to contact Boeing for appropriate action, and specifies that action as “RC” (Required for Compliance): Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (j) of this AD.
As of the effective date of this AD: A horizontal stabilizer may be installed on any airplane, provided all applicable actions required by the introductory text of paragraph (g) and paragraphs (g)(1) and (g)(2) of this AD are done within the compliance times specified in the introductory text of paragraph (g) of this AD, and in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-55A1092, dated August 7, 2015, except as required by paragraph (h) of this AD.
