Airworthiness Directive · Amendment 39-18838 · Horizontal stabilizer
The Boeing Company Airplanes
(1) This AD applies to The Boeing Company Model 737-300, -400, and -500 series airplanes, certificated in any category, as identified in Boeing Special Attention Service Bulletin 737-55-1059, Revision 1, dated April 6, 2016 (“SASB 737-55-1059 R1”).
(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 certain The Boeing Company Model 737-300, -400, and -500 series airplanes. This AD was prompted by reports of cracks in the horizontal stabilizer lower skins. This AD requires inspections for cracking of the horizontal stabilizer lower skin, and corrective actions if necessary; and also provides actions that would terminate certain repetitive inspections. We are issuing this AD to address the unsafe condition on these products.
For any Configuration 1 horizontal stabilizer on Group 1 airplanes, as identified in SASB 737-55-1059 R1: Except as specified in paragraph (i)(1) of this AD, at the applicable time specified in paragraph 1.E., “Compliance,” of SASB 737-55-1059 R1, do a detailed inspection for cracking of the horizontal stabilizer lower skin; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of SASB 737-55-1059 R1, except as specified in paragraph (i)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspection of the horizontal stabilizer lower skin, if applicable, thereafter at the applicable intervals specified in paragraph 1.E., “Compliance,” of SASB 737-55-1059 R1. Options specified in SASB 737-55-1059 R1 for accomplishing the inspections are acceptable for the corresponding requirements of this paragraph provided that the inspections are done at the applicable times in paragraph 1.E., “Compliance,” of the SASB 737-55-1059 R1.
For any Configuration 2 horizontal stabilizer on Group 1 airplanes, as identified in SASB 737-55-1059 R1: Except as specified in paragraph (i)(1) of this AD, at the applicable time specified in paragraph 1.E., “Compliance,” of SASB 737-55-1059 R1, do the actions specified in paragraphs (h)(1), (h)(2), and (h)(3) of this AD; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of SASB 737-55-1059 R1, except as specified in paragraph (i)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the inspections specified in paragraphs (h)(1), (h)(2), and (h)(3) of this AD, if applicable, thereafter at the applicable intervals specified in paragraph 1.E., “Compliance,” of SASB 737-55-1059 R1. Options specified in SASB 737-55-1059 R1, for accomplishing the inspections are acceptable for the corresponding requirements of this paragraph provided that the inspections are done at the applicable times in paragraph 1.E., “Compliance,” of SASB 737-55-1059 R1.
(1) Do a high frequency eddy current inspection for cracking of the skin around any repair common to the rear spar lower chord between station (STA) 83.50 and STA 249.10 which was done as specified in the structural repair manual or any external doubler repair, and a detailed inspection for any loose or any missing fastener of repaired doublers, except as specified in paragraph (i)(3) of this AD.
(2) Do a detailed inspection for cracking of the inspar lower skin between STA 83.50 and STA 249.10, except in areas repaired common to the rear spar lower chord.
(3) Do a low frequency eddy current inspection for cracking of the forward fastener row of any external doubler repair common to the rear spar lower chord between STA 83.50 and STA 249.10.
(1) Where SASB 737-55-1059 R1 specifies a compliance time “after the Revision 1 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, corrosion, hole elongation, or loose or missing fastener is found during any inspection required by this AD, and SASB 737-55-1059 R1 specifies to contact Boeing for repair instructions: Before further flight, repair the cracking, corrosion, hole elongation, loose or missing fasteners using a method approved in accordance with the procedures specified in paragraph (j) of this AD.
(3) Where SASB 737-55-1059 R1 specifies that doublers installed with solid rivets do not need to be inspected for loose or missing fasteners, this AD does not require doublers installed with solid rivets or Hi-lok fasteners to be inspected for loose or missing fasteners.
