Airworthiness Directive · Amendment 39-18581 · Stabilizers
The Boeing Company Airplanes
Superseded. A later AD replaced this one: AD 2018-23-09. Comply with the one in force.
(1) This AD applies to all The Boeing Company Model 737-600, -700, -700C, -800, -900, and 900ER series airplanes, certificated in any category.
(2) Installation of Supplemental Type Certificate (STC) ST00830SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/184de9a71ec3fa5586257eae00707da6/$FILE/ST00830SE.pdf) 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 all The Boeing Company Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. This AD was prompted by reports of a manufacturing oversight, in which a supplier omitted the required protective finish on certain bushings installed in the rear spar upper chord on horizontal stabilizers, which could lead to galvanic corrosion and consequent cracking of the rear spar upper chord. This AD requires an inspection or records check to determine if affected horizontal stabilizers are installed, related investigative actions, and for affected horizontal stabilizers, repetitive inspections for any crack of the horizontal stabilizer rear spar upper chord, and corrective action if necessary. We are issuing this AD to detect and correct cracking of the rear spar upper chord, which can result in the failure of the upper chord and consequent departure of the horizontal stabilizer from the airplane, which can lead to loss of control of the airplane.
(1) Except as specified in paragraph (h)(1) of this AD, within the compliance time identified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, do the actions specified in paragraph (g)(1)(i) or (g)(1)(ii) of this AD.
(i) Do a records check to determine if an affected horizontal stabilizer is installed and if any horizontal stabilizer has been exchanged, and do all applicable related investigative actions, in accordance with Part 1 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015. Affected horizontal stabilizers are identified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015.
(ii) Do an inspection of the horizontal stabilizer identification plate to determine if any affected horizontal stabilizer is installed, in accordance with Part 2 of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015. Affected horizontal stabilizers are identified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015.
(2) If, during any action required by paragraph (g)(1)(i) or (g)(1)(ii) of this AD, any affected horizontal stabilizer is found: Except as specified in paragraph (h)(1) of this AD, within the compliance time identified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, do a high frequency eddy current (HFEC) inspection for any crack of the horizontal stabilizer rear spar upper chord and do all applicable corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, except as required by paragraph (h)(2) of this AD. Repeat the inspection thereafter at intervals identified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015.
(1) Where Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, 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.
(2) If any cracking is found during any inspection required by this AD, and Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, specifies to contact Boeing for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (j) of this AD, or replace with a serviceable horizontal stabilizer as specified in paragraph (i) of this AD.
As of the effective date of this AD, no person may install a horizontal stabilizer on any airplane, except as specified in paragraphs (i)(1) and (i)(2) of this AD.
(1) A horizontal stabilizer may be installed if the part is inspected in accordance with “Part 2: Horizontal Stabilizer Identification Plate Inspection” of the Accomplishments Instructions of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, and no affected serial number is found.
(2) A horizontal stabilizer may be installed if the part is inspected in accordance with “Part 2: Horizontal Stabilizer Identification Plate Inspection” of the Accomplishments Instructions of Boeing Alert Service Bulletin 737-55A1097, dated July 1, 2015, and an affected serial number is found, provided that the actions specified in paragraphs (i)(2)(i) and (i)(2)(ii) of this AD are done, as applicable.
(i) Initial and repetitive HFEC inspections specified in paragraph (g)(2) of this AD are completed within the compliance times specified in paragraph (g)(2) of this AD.
(ii) All applicable corrective actions are done before further flight as required by paragraph (h)(2) of this AD.
