# AD 91-05-02: Landing Gear Mount - Type: Airworthiness directive - Status: Current - Products: SOCATA TB 20 and TB 21 - Effective: March 25, 1991 - Superseded by: Nothing supersedes this AD - Product type: Aircraft, Small airplane - Amendment: 39-6887 - Docket: 90-CE-20-AD - Registered aircraft: 250 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/2BBDA553130553DC86256A64006A65BB.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/91-05-02 ## The airworthiness directive 91-05-02 SOCATA: Amendment 39-6887. Docket No. 90-CE-20-AD. Applicability: Models TB 20 and TB 21 airplanes (serial numbers (S/N) 1 through 1051, except S/N 1040 and S/N 1042), certificated in any category. Compliance: Required as indicated after the effective date of this AD, unless already accomplished. To prevent structural failure of the fuselage frame in the area of the landing gear attachment, accomplish the following: (a) On airplanes with more than 1,500 hours time-in-service (TIS) on the effective date of this AD, within the next 100 hours TIS after the effective date of this AD and, thereafter, at intervals not to exceed 500 hours TIS, visually inspect the fuselage frame No. 0 for cracks in the area of the engine mount and landing gear mount in accordance with the instructions in Aerospatiale Service Bulletin (SB) No. 42/1, dated July 1990. Prior to further flight, repair any cracked frames found in accordance with the instructions in the above SB.(b) On airplanes with less than 1,500 hours TIS on the effective date of this AD, within the next 100 hours TIS or prior to accumulating 1,600 hours TIS, whichever occurs later, and, thereafter, at intervals not to exceed 500 hours TIS, visually inspect the fuselage frame No. 0 for cracks in the area of the engine mount and landing gear mount in accordance with the instructions in Aerospatiale SB No. 42/1, dated July 1990. Prior to further flight repair any cracked frames found per the instructions in the above SB. (c) The repetitive inspections specified in paragraphs (a) and (b) of this AD are no longer required when the airplane has been modified in accordance with Socata Kit 9152. (d) 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. (e) An alternate method of compliance or adjustment of the initial or repetitive compliance times that provides an equivalent level of safety may be approved by the Manager, Aircraft Certification Office, Europe, Africa, Middle East Office, FAA, c/o American Embassy, B-1000, Brussels, Belgium. The request should be forwarded through an appropriate FAA Maintenance Inspector, who may add comments and then send it to the Manager, Brussels Aircraft Certification Office. (f) All persons affected by this directive may obtain copies of the documents referred to herein upon request to Aerospatiale Aeroport Tarbes-Ossum-Lourdes, B.P. 930 65009 Tarbes, France; Telephone 62.51.7300; or may examine the service information at the FAA, Central Region, Office of the Assistant Chief Counsel, Room 1558, 601 E. 12th Street, Kansas City, Missouri 64106. This amendment (39-6887, AD 91-05-02) becomes effective on March 25, 1991. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS A51EU](https://openairdocs.org/tcds/A51EU): Daher Aerospace; names 2 of 5 models: TB 21, TB 20 ## Registered aircraft it may apply to (OpenAirDocs) Matched by airframe and engine model; the AD's applicability may narrow it by serial number, part number or equipment. - Aircraft: 250 (250 by airframe model, 0 by engine model) - Makers: Socata 250 Models with the most aircraft: - [Socata TB-20 TRINIDAD](https://openairdocs.org/model/socata-tb-20-trinidad): 175 aircraft (airframe model) - [Socata TB21](https://openairdocs.org/model/socata-tb21): 50 aircraft (airframe model) - [Socata TB20](https://openairdocs.org/model/socata-tb20): 25 aircraft (airframe model) All 3 models: https://openairdocs.org/ad/91-05-02/models.md Every aircraft: https://openairdocs.org/ad/91-05-02/aircraft.md 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.