# AD 91-14-20: Structural Inspection - Type: Airworthiness directive - Status: Historical - Products: Boeing 737 Series (all) - Effective: August 9, 1991 - Superseded by: [AD 98-11-04 R1](https://openairdocs.org/ad/98-11-04-R1) - Product type: Aircraft, Large airplane - Amendment: 39-7061 - Docket: 91-NM-19-AD - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/414AA63D487BBB7B86256A18006F2475.0001 - DRS record last changed: August 7, 2025 - Page: https://openairdocs.org/ad/91-14-20 ## The airworthiness directive 91-14-20 BOEING: Amendment 39-7061. Docket No. 91-NM-19-AD. Supersedes AD 84-21- 06 R1. Applicability: Model 737 series airplanes; listed in Section 3.0 of Boeing Document No. D6-37089, Revision C, "Supplemental Structural Inspection Document" (SSID), dated January 1990; certificated in any category. Compliance: Required as indicated, unless previously accomplished. To ensure the continuing structural integrity of the Model 737 fleet, accomplish the following: A. For airplanes identified in Boeing Document D6-37089, Revision B, dated February 18, 1987: Within three months after April 8, 1988 (the effective date of Amendment 39-5813, AD 84-21-06 R1), incorporate a revision in the FAA-approved maintenance inspection program which provides no less than the required damage tolerance rating (DTR) for each Structural Significant Item (SSI) listed in Boeing Document No. D6-37089, "Supplemental Structural Inspection Document" (SSID), Revision B, dated February 18, 1987. The required DTR value for each SSI is listed in the document. The revision to the maintenance program shall include and be implemented in accordance with the procedures in Sections 5.0 and 6.0 of Revision B of the SSID. B. For airplanes identified in Boeing Document D6-37089, Revision C, dated January 1990: Within 1 year after the effective date of this amendment, incorporate a revision into the FAA-approved maintenance inspection program which provides no less than the required DTR for each SSI listed in Boeing Document D6-37089, "SSID," Revision C, dated January 1990. The required DTR value for each SSI is listed in the document. The revision to the maintenance program shall include and be implemented in accordance with the procedures in Sections 5.0 and 6.0 of Revision C of the SSID. C. Cracked structure must be repaired, prior to further flight, in accordance with an FAA-approved method. D. An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who may concur or comment and then send it to the Manager, Seattle ACO. E. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. F. The inspection requirements shall be done in accordance with Boeing Document No. D6-37089, Revision C, dated January 1990, which includes the following list of affected pages: C. Cracked structure must be repaired, prior to further flight, in accordance with an FAA-approved method. D. An alternative method of compliance or adjustment of the compliance time, which provides an acceptable level of safety, may be used when approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. NOTE: The request should be forwarded through an FAA Principal Maintenance Inspector (PMI), who may concur or comment and then send it to the Manager, Seattle ACO. E. Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base in order to comply with the requirements of this AD. F. The inspection requirements shall be done in accordance with Boeing Document No. D6-37089, Revision C, dated January 1990, which includes the following list of affected pages: SECTION PAGE NUMBER REVISION LEVEL VOLUME 1 A 1 - 13, C 13.1 - 13.3, 24 - 30 23 B B 1 B 2 C C 1 C 1.0 1 - 2 C 2.0 1 (Original Issue) 2, 4 C 3 B 3.0 1 - 3 C 4.0 3 (Original Issue) 4 C 5.0 1, 4, 6, 7, 9 C 5 B 2, 3, 8 A 6.0 1, 2, 2.1 C 7.0 3, 4, 6, 8 C 5, 7 B 8.0 1, 3 B 2, 4 C 8.1 1 - 3, W.10.3, C W.17.1, W.17.9, W.17.15, W.19.2 - W.19.4, W.19.6, W.27.1, W.27.5 - W.27.7, W.27.15, W.27.16, W.31.1, W.42.1 - W.42.3 W.10.4, W.17.2, W.17.10, B W.19.1, W.19.5, W.27.2, W.27.8 W.42.4 A 4, W.17.16, W.31.2, (Original Issue) 8.2 1 - 4, F.1.2, F.3.1, F.3.2, C F.4.0 - F.4.2, F.10.0, F.10.1, F.11.0, F.11.1, F.12.0, F.12.1, F.12.2, F.13.2 - F.13.5, F.14.2 - F.14.5, F.17.2, F.17.3, F.17.3.1 - F.17.3.3, F.17.4 - F.17.8, F.18.2 - F.18.5, F.20.1, F.20.2, F.38.1, F.38.7, F.38.8, F.39.1 - F.39.9, F.45.0 - F.45.2 F.1.1, F.10.2, F.11.2, B F.18.1, F.38.2 F.17.1.3 A F.9.3, F.10.7, F.13.1, (Original Issue) F.14.0, F.14.1, F.15.0, F.19.0, F.39.10 8.3 1 - 3, E.14.2, C E.19.2, E.19.4, E.20.1 E.1.0, E.20.2 (Original Issue) 9 1 C 10.2.1 1, 2, 4, 5, 7 - 9, C 16, 20, 21, 27, 28, 30 3, 6, 10, 15, 19, (Original Issue) 22, 29 10.5 1, 6 C 2 B 5 (Original Issue) VOLUME 2 11.0 1 C 11.1 1 - 3 C 11.2 1 - 3 CF.1, F.3, F.4, F.12, F.13A, F.13B, F.14A, F.14B, F.17A, F.17B, F.17C, F.17D, F.17E, F.18A, F.18B, F.20, F.38A, F.38B, F.39A 11.3 1, 2 C This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR Part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124. Copies may be inspected at the FAA, Northwest Mountain Region, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, Washington, or at the Office of the Federal Register, 1100 L Street NW., Room 8401, Washington, D.C. Airworthiness Directive 91-14-20, supersedes AD 84-21-06 R1, Amendment 39-4933. This amendment (39-7061, AD 91-14-20) becomes effective on August 9, 1991. ## Registered aircraft it may apply to (OpenAirDocs) No registered aircraft matched the models it names. ## Related documents - [AD 98-11-04 R1](https://openairdocs.org/ad/98-11-04-R1): Structural Inspection ยท Boeing 737-100 Series, 737-200 Series and 737-200C Series. Effective Jun 23, 1998. Supersedes this AD Its text cites no advisory circulars or STCs. --- OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.