Airworthiness Directive · Amendment 39-17207 · Fuselage
The Boeing Company Airplanes
This AD applies to The Boeing Company Model 737-100, -200, and -200C series airplanes; certificated in any category; as identified in Boeing Special Attention Service Bulletin 737-53-1313, dated November 3, 2011.
We are adopting a new airworthiness directive (AD) for certain The Boeing Company Model 737-100, -200, and -200C series airplanes. This AD was prompted by a report of a severed upper butt strap, and cracks in the forward skin and bonded doubler, on one airplane. This AD requires repetitive inspections for cracks and a chemical spot test in the area of station (STA) 908, and related investigative and corrective actions, if necessary. For certain airplanes, this AD requires an inspection and modification. We are issuing this AD to prevent cracks at the adjacent mating skins (forward and aft), which could initiate just above stringers S-4R and S-4L; and could grow and result in a decompression event.
For Group 1 airplanes, as identified in Boeing Special Attention Service Bulletin 737-53-1313, dated November 3, 2011: Within 120 days after the effective date of this AD, inspect and modify, as required, using a method approved in accordance with the procedures specified in paragraph (k) of this AD.
For Groups 2 and 3 airplanes, as identified in Boeing Special Attention Service Bulletin 737-53-1313, dated November 3, 2011: Except as provided by paragraph (i)(1) of this AD, at the applicable times identified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 737-53-1313, dated November 3, 2011, do the actions specified in paragraphs (h)(1) and (h)(2) of this AD, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-53-1313, dated November 3, 2011, except as provided by paragraph (i)(2) of this AD.
(1) Do one of the inspection options identified in paragraphs (h)(1)(i), (h)(1)(ii), and (h)(1)(iii) of this AD; and do all applicable related investigative and corrective actions. Do all applicable related investigative and corrective actions before further flight.
(i) Inspection Option 1: Do a detailed inspection for cracks of the station (STA) 908 forward and aft skin. Thereafter, repeat the inspection at intervals not to exceed 500 flight cycles until the chemical spot test required by paragraph (h)(2) of this AD is done.
(ii) Inspection Option 2: Do a one-time external low-frequency eddy current (LFEC) inspection for cracks of the STA 908 upper butt strap.
(iii) Inspection Option 3: Do a one-time internal LFEC inspection for cracks of the STA 908 upper butt strap.
(2) Do a chemical spot test of the STA 908 upper butt strap to determine the part material, and do all applicable related investigative and corrective actions. Do all applicable related investigative and corrective actions at the times specified in paragraph 1.E., “Compliance,” of Boeing Special Attention Service Bulletin 737-53-1313, dated November 3, 2011, except as provided by paragraph (i)(1) of this AD. Confirming the upper butt strap is made from 2000 series aluminum terminates the inspections required by paragraph (h)(1) of this AD.
(1) Where Boeing Special Attention Service Bulletin 737-53-1313, dated November 3, 2011, specifies a compliance time “after the original issue date of the service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.
(2) Where Boeing Special Attention Service Bulletin 737-53-1313, dated November 3, 2011, specifies to contact Boeing for repair instructions: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (k) of this AD.
Replacing the STA 908 upper butt strap and doing all applicable related investigative and corrective actions, in accordance with Part 4, Part 5, and Part 6, of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-53-1313, dated November 3, 2011, except as provided by paragraph (i)(2) of this AD, terminates the inspections and chemical spot test required by this AD.
