Airworthiness Directive · Amendment 39-17452 · Doors
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/0/2C6E3DBDDD36F91C862576A4005D64E2?OpenDocument&Highlight=st01219se) 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 superseding an existing airworthiness directive (AD) for all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. That AD currently requires repetitive inspections to detect cracking of the lower corners of the door frame and cross beam of the forward cargo door, and corrective actions if necessary. That AD also requires eventual modification of the outboard radius of the lower corners of the door frame and reinforcement of the cross beam of the forward cargo door, which terminates the existing repetitive inspections. This new AD revises the compliance times for the preventive modification; adds certain inspections for cracks in the number 5 cross beam of the forward cargo door; and adds inspections of the number 4 cross beam if cracks are found in the number 5 cross beam, and corrective actions if necessary. For certain airplanes, this new AD also adds a one-time inspection for airplanes previously modified or repaired, and a one-time inspection of the reinforcement angle for excessive shimming or fastener pull-up, and corrective actions if necessary. This AD was prompted by additional reports of fatigue cracking in the radius of the lower frames and in the lower number 5 cross beam of the forward cargo door. We are issuing this AD to prevent fatigue cracking of the lower corners of the door frame and number 5 cross beam of the forward cargo door, which could result in rapid depressurization of the airplane.
This paragraph restates the requirements of paragraph (a) of AD 2000-07-06, Amendment 39-11660 (65 FR 19302, April 11, 2000), with revised service information. Within 1 year or 4,500 flight cycles after May 16, 2000 (the effective date of AD 2000-07-06), whichever occurs later, perform an HFEC inspection to detect cracking of the lower corners (forward and aft) of the door frame of the forward cargo door, in accordance with Figure 4 or Figure 23, of Section 51-00-00, of Part 6, of Boeing 737 Nondestructive Test (NDT) Manual, D6-37239, dated August 5, 1997, as applicable; or Procedure 4 or Procedure 23, of Section 51-00-00, of Part 6, of Boeing 737 Nondestructive Test (NDT) Manual, D6-37239, Revision 108, dated November 15, 2012; as applicable.
Note 1 to paragraphs (g), (h), (i), and (j) of this AD: Accomplishment of Boeing Service Bulletin 737-52-1100, Revision 2, dated March 31, 1994, does not supersede the requirements of AD 90-06-02, Amendment 39-6489 (55 FR 8372, March 7, 1990).
(1) If no cracking is detected, repeat the HFEC inspection thereafter at intervals not to exceed 4,500 flight cycles, until the requirements of paragraph (i) of this AD have been accomplished.
(2) If any cracking is detected during any inspection required by paragraph (g) of this AD, prior to further flight, accomplish the requirements of paragraphs (g)(2)(i) and (g)(2)(ii) of this AD, which constitute terminating action for the repetitive inspections required by paragraph (g)(1) of this AD.
(i) Accomplish the requirements of paragraph (g)(2)(i)(A) or (g)(2)(i)(B) of this AD, and install a cross beam repair and reinforcement modification of the cross beam, in accordance with Boeing Service Bulletin 737-52-1100, Revision 2, dated March 31, 1994.
(A) Repair the door frame of the forward cargo door in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), Transport Airplane Directorate, FAA; or in accordance with data meeting the type certification basis of the airplane approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Seattle ACO, to make such findings. For a repair or modification method to be approved by the Manager, Seattle ACO, as required by this paragraph, and paragraphs (g)(2)(ii), (h)(2), (h)(3)(ii), and (i)(2) of this AD, the Manager's approval letter must specifically reference this AD.
(B) Replace the door frame of the forward cargo door with a new door frame, in accordance with Boeing Service Bulletin 737-52-1100, Revision 2, dated March 31, 1994.
(ii) Modify the repaired or replaced door frame of the forward cargo door, in accordance with a method approved by the Manager, Seattle ACO, or in accordance with data meeting the type certification basis of the airplane approved by the Boeing Commercial Airplanes ODA that has been authorized by the Manager, Seattle ACO, to make those findings.
This paragraph restates the requirements of paragraph (b) of AD 2000-07-06, Amendment 39-11660 (65 FR 19302, April 11, 2000). Within 1 year or 4,500 flight cycles after May 16, 2000 (the effective date of AD 2000-07-06), whichever occurs later, perform a detailed inspection to detect cracking of the cross beam (i.e., upper and lower chord and web sections) of the forward cargo door, in accordance with Boeing Service Bulletin 737-52-1100, Revision 2, dated March 31, 1994. For the purposes of this AD, a detailed inspection is: An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.
(1) If no cracking is detected, repeat the inspection thereafter at intervals not to exceed 4,500 flight cycles until the requirements of paragraph (i) of this AD have been accomplished.
(2) If any cracking is detected on the lower chord section of the cross beam during any inspection required by paragraph (h) of this AD, prior to further flight, repair in accordance with a method approved by the Manager, Seattle ACO, or in accordance with data meeting the type certification basis of the airplane approved by the Boeing Commercial Airplanes ODA that has been authorized by the Manager, Seattle ACO, to make those findings.
(3) If any cracking is detected on any area excluding the lower chord section of the cross beam (i.e., upper chord and web section) during any inspection required by paragraph (h) of this AD, prior to further flight, accomplish the requirements of paragraph (h)(3)(i) or (h)(3)(ii) of this AD, as applicable, which constitutes terminating action for the repetitive inspections required by paragraph (h)(1) of this AD.
(i) For airplanes with line numbers 1 through 1231 inclusive: Install a cross beam repair and preventative modification of the outboard radius of the lower corners (forward and aft) of the door frame, in accordance with Boeing Service Bulletin 737-52-1100, Revision 2, dated March 31, 1994.
(ii) For airplanes with line numbers 1232 and subsequent: Install a cross beam repair and preventative modification of the outboard radius of the lower corners (forward and aft) of the door frame, in accordance with a method approved by the Manager, Seattle ACO, or in accordance with data meeting the type certification basis of the airplane approved by the Boeing Commercial Airplanes ODA that has been authorized by the Manager, Seattle ACO, to make those findings.
This paragraph restates the requirements of paragraph (c) of AD 2000-07-06, Amendment 39-11660 (65 FR 19302, April 11, 2000), with revised service information. Within 4 years or 12,000 flight cycles after May 16, 2000 (the effective date of AD 2000-07-06), whichever occurs later: Install the preventative modification of the outboard radius of the lower corners (forward and aft) of the door frame and the reinforcement modification of the cross beam of the forward cargo door, in accordance with paragraph (i)(1) or (i)(2) of this AD, as applicable. Accomplishment of paragraph (i)(1) or (i)(2) of this AD, as applicable, constitutes terminating action for the repetitive inspections required by paragraphs (g)(1) and (h)(1) of this AD.
(1) For airplanes with line numbers 1 through 1231 inclusive: Accomplish the preventative modification and the reinforcement modification, in accordance with Boeing Service Bulletin 737-52-1100, Revision 2, dated March 31, 1994.
(2) For airplanes with line numbers 1232 and subsequent: Accomplish the preventative modification and the reinforcement modification, in accordance with a method approved by the Manager, Seattle ACO, or in accordance with data meeting the type certification basis of the airplane approved by the Boeing Commercial Airplanes ODA that has been authorized by the Manager, Seattle ACO, to make those findings; or in accordance with Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011. As of the effective date of this AD, use only Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011, to accomplish the modifications required by this paragraph.
This paragraph restates the requirements of paragraph (d) of AD 2000-07-06, Amendment 39-11660 (65 FR 19302, April 11, 2000). For all airplanes on which modifications of the forward lower corner of the door frame and the cross beam of the forward cargo door were accomplished as specified in Boeing Service Bulletin 737-52-1100, dated August 25, 1988, or Revision 1, dated July 20, 1989; or in accordance with the requirements of AD 90-06-02, Amendment 39-6489 (55 FR 8372, March 7, 1990): Within 4 years or 12,000 flight cycles after May 16, 2000 (the effective date of AD 2000-07-06), whichever occurs later, install the reinforcement modification of the aft corner of the door frame of the forward cargo door, in accordance with Boeing Service Bulletin 737-52-1100, Revision 2, dated March 31, 1994. Accomplishment of such modification constitutes terminating action for the repetitive inspections required by paragraphs (g)(1) and (h)(1) of this AD.
Except as provided by paragraphs (m)(1) and (m)(2) of this AD: At the applicable time specified in paragraph 1.E, “Compliance,” of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011, do the inspections required by paragraphs (k)(1) and (k)(2) of this AD, as applicable. Do all applicable related investigative and corrective actions before further flight, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011; except as required by paragraph (m)(3) of this AD. Accomplishment of the inspections required by paragraph (k) of this AD terminates the requirements of the repetitive inspections required by paragraphs (g)(1) and (h)(1) of this AD. If any cracking is found in the number 4 cross beam, before further flight, repair in accordance with Boeing Special Attention Service Bulletin 737-52-1149, dated December 11, 2003.
Note 2 to paragraph (k) of this AD: Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011, refers to Boeing Special Attention Service Bulletin 737-52-1149, dated December 11, 2003, as an additional source of guidance for the inspection for cracks of the number 4 cross beam.
(1) For airplanes identified in Tables 1 and 2 of paragraph 1.E, “Compliance,” of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011: Do a one-time HFEC inspection of the applicable location for cracks, in accordance with the Work Instructions, Part I, of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011.
(2) For airplanes identified in Table 3 of paragraph 1.E, “Compliance,” of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011: Do a one-time general visual inspection of the reinforcement angle for excessive shimming or fastener pull-up, in accordance with the Work Instructions, Part III, of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011.
(1) The supplemental structural inspections specified in Table 4 of paragraph 1.E., “Compliance,” and Part 5 of the Accomplishment Instructions, of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011, are not required by this AD.
(2) The supplemental structural inspections specified in Table 4 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011, may be used in support of compliance with section 121.1109(c)(2) or 129.109(b)(2) of the Federal Aviation Regulations (14 CFR 121.1109(c)(2) or 14 CFR 129.109(b)(2)). The corresponding actions specified in the Accomplishment Instructions of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011, are not required by this AD.
(1) Where paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011, specifies a compliance time relative to the Revision 5 issue date of that service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.
(2) Where Table 1, “Condition” column of Paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011, specifies “airplanes without either the repair or modification accomplished in accordance with previous releases of this service bulletin,” the corresponding condition in this AD is for “airplanes on which either a repair or modification was not accomplished before the effective date of this AD.”
(3) Where Boeing Alert Service Bulletin 737-52A1100, Revision 5, dated February 14, 2011, specifies to contact Boeing for certain actions: Before further flight, do the repair using a method approved in accordance with the procedures specified in paragraph (n)(1) of this AD.
