Airworthiness Directive · Amendment 39-19124 · Stabilizers
The Boeing Company Airplanes
(1) This AD applies to all The Boeing Company Model 737-100, -200, -200C, -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 737-100, -200, -200C, -300, -400, and -500 series airplanes. This AD was prompted by a report indicating that wear of the bearing plate slider bushings could cause disconnection of certain elevator hinges, which could excite the horizontal stabilizer under certain in-flight speed/altitude conditions and lead to degradation of the structure. This AD requires repetitive inspections and checks of certain elevator hinges and related components, repetitive replacements and tests of the bearing plate, and related investigative and corrective actions, if necessary. We are issuing this AD to address the unsafe condition on these products.
For airplanes identified as Group 1 in Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016: Within 120 days after the effective date of this AD, do inspections and checks of the elevator and horizontal stabilizer at elevator hinge numbers 4 and 6 and the replacement and test of the bearing plate at elevator hinge numbers 4 and 6, and do all applicable related investigative and corrective actions, using a method approved in accordance with the procedures specified in paragraph (m) of this AD.
For airplanes identified as Groups 2 and 3 in Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016: Except as required by paragraph (j)(1) of this AD, at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016, do the applicable inspections and checks of elevator hinge numbers 4 and 6 and related components specified in paragraphs (h)(1) through (h)(8) of this AD, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016, except as required by paragraph (j)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the actions specified in paragraphs (h)(1) through (h)(8) of this AD thereafter at the applicable times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016.
(1) For Groups 2 and 3 airplanes: A high frequency eddy current (HFEC) inspection for cracking of the elevator hinge numbers 4 and 6.
(2) For Groups 2 and 3 airplanes: A loose bolt check at elevator hinge numbers 4 and 6.
(3) For Groups 2 and 3 airplanes: An HFEC inspection and low frequency eddy current (LFEC) inspection for cracking of the horizontal stabilizer forward of elevator hinge numbers 4 and 6.
(4) For Groups 2 and 3 airplanes: A loose bolt check of horizontal stabilizer attach plates at elevator hinge numbers 4 and 6.
(5) For Groups 2 and 3 airplanes: A detailed inspection of the horizontal stabilizer rear spar outer mold line, gusset plate, and inspar skin for any corrosion.
(6) For Group 2, Configuration 2, and Group 3 airplanes: A general visual inspection of the elevator front spar around hinge numbers 4 and 6 for any ply damage.
(7) For Group 2 and 3 airplanes: A tap test inspection of the elevator skin for any delamination at elevator hinge numbers 4 and 6.
(8) For Group 2, Configuration 2, and Group 3 airplanes on which elevator hinge fitting assembly 65C31307-() is installed at elevator hinge number 6: An HFEC inspection of the hinge fitting for any crack.
For airplanes identified as Group 2, Configuration 2, and Group 3 in Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016: Except as required by paragraph (j)(1) of this AD, at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016, do the actions specified in paragraphs (i)(1) and (i)(2) of this AD, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016, except as required by paragraph (j)(2) of this AD. All applicable related investigative and corrective actions must be done before further flight. Repeat the actions specified in paragraphs (i)(1) and (i)(2) of this AD thereafter at the applicable time specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016.
(1) Replace the bearing plates at elevator hinge numbers 4 and 6.
(2) Do an elevator hinge bearing plate binding test at elevator hinge numbers 4 and 6.
(1) Where Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016, 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) Although Boeing Alert Service Bulletin 737-55A1099, Revision 1, dated October 21, 2016, specifies to contact Boeing for repair instructions, and specifies that action as “RC” (Required for Compliance), this AD requires repair before further flight using a method approved in accordance with the procedures specified in paragraph (m) of this AD.
As of the effective date of this AD: A horizontal stabilizer, an elevator, or a bearing plate may be installed on any airplane, provided the actions required by paragraphs (h) and (i) of this AD are done within the applicable compliance times specified in paragraphs (h) and (i) of this AD.
