# SAIB AIR-21-20: TE FLAP CONTROL SYSTEM, Flight Controls –Flap Cable Tension - Type: Special airworthiness information bulletin (advisory, not mandatory) - Status: Current - Revision: 0 - Issued: December 16, 2021 - Products: Textron 310, 310A, 310B, 310C, 310D, 310F, 310G, 310H, 310I, 310J, 310J-1, 310K and 32 more - Product type: Aircraft, Small Airplane - PDF: https://openairdocs.org/files/sha256/84/0d/840d6df6c0dad413d83a330b9c650e436705ce38c7fd63088c41d13c31441ab9 - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/DRSDOCID754822668202112231709440.0001 - DRS record last changed: November 21, 2025 - Page: https://openairdocs.org/saib/AIR-21-20 ## Text FAA Aviation Safety **SPECIAL AIRWORTHINESS** INFORMATION BULLETIN SUBJ: TE FLAP CONTROL SYSTEM, Flight Controls –Flap Cable Tension SAIB: AIR-21-20 Date: December 16, 2021 This is information only. Recommendations aren’t mandatory. Introduction This special airworthiness information bulletin (SAIB) alerts owners, operators, maintenance technicians, and inspectors of an airworthiness concern on Textron Aviation Inc. (formerly Cessna Aircraft Company) Model 310, 310A, 310B, 310C, 310D, 310F, 310G, 310H, 310I, 310J, 310J-1, 310K, 310L, 310N, 310P, 310Q, 310R, 320, 320-1, 320A, 320B, 320C, 320D, 320E, 320F, 335, 340, 340A, 401, 401A, 401B, 402, 402A, 402B, 402C, 411, 411A, 414, 414A, 421, 421A, 421B, 421C, and 425 airplanes. The intent is to emphasize the importance of ensuring control cable tensions are set correctly during airplane maintenance, particularly when similar cables require different tensioning. At this time, the airworthiness concern is not an unsafe condition that would warrant airworthiness directive (AD) action under Title 14 of the Code of Federal Regulations (14 CFR) part 39. Background The FAA received a report of an event that occurred on November 26, 2019, where the flap extend cable failed during approach. The pilot felt a sudden right roll and right yaw, which they corrected with near full left aileron and left rudder. When the flaps were retracted, the airplane became controllable again. A no-flap landing was conducted, and the aircraft rolled out and stopped without further incident. A search of the FAA’s service difficulty report (SDR) system revealed 24 similar events of flap extend cable failure over the last 35 years, all without a serious outcome. The FAA suspects improper tensioning as a contributing factor in the flap extend cable failures. The flap extend cable has a specified tension significantly lower than the retract cable. In general, improper tensioning of the flight control cables may result in cable failure or interference with airplane structure. Textron has revised their manuals for the airplane models listed above to emphasize the differences between extension and retraction rigging tensions. Recommendations The FAA recommends using the latest revision of the applicable service manual to ensure control cable extension and retraction rigging tensions are set correctly during airplane maintenance. For Further Information Contact Adam Hein, Aviation Safety Engineer, Wichita ACO Branch, FAA, 1801 Airport Rd, Wichita, KS 67209; phone: (316) 946-4116; fax: (316) 946-4107; e-mail: adam.hein@faa.gov. 2 For Related Service Information Contact Textron Aviation Customer Service, P.O. Box 7706, Wichita, KS 67277; phone: (316) 517-5800; fax: (316) 517-7271; email: customercare@txtav.com; website: www.txtav.com. ## Registered aircraft it may concern (OpenAirDocs) Registry models matched by make and model, the same way as ADs, most registered aircraft first. - [Cessna 340A](https://openairdocs.org/model/cessna-340a): 543 registered aircraft (airframe model) - [Cessna 421C](https://openairdocs.org/model/cessna-421c): 496 registered aircraft (airframe model) - [Cessna 414A](https://openairdocs.org/model/cessna-414a): 363 registered aircraft (airframe model) - [Cessna 310R](https://openairdocs.org/model/cessna-310r): 361 registered aircraft (airframe model) - [Cessna 310Q](https://openairdocs.org/model/cessna-310q): 277 registered aircraft (airframe model) - [Cessna 414](https://openairdocs.org/model/cessna-414): 242 registered aircraft (airframe model) - [Cessna 421B](https://openairdocs.org/model/cessna-421b): 225 registered aircraft (airframe model) - [Cessna 340](https://openairdocs.org/model/cessna-340): 164 registered aircraft (airframe model) - [Cessna 425](https://openairdocs.org/model/cessna-425): 161 registered aircraft (airframe model) - [Cessna 402C](https://openairdocs.org/model/cessna-402c): 115 registered aircraft (airframe model) - [Cessna 310](https://openairdocs.org/model/cessna-310): 103 registered aircraft (airframe model) - [Cessna 310K](https://openairdocs.org/model/cessna-310k): 78 registered aircraft (airframe model) - [Cessna 310L](https://openairdocs.org/model/cessna-310l): 62 registered aircraft (airframe model) - [Cessna 310P](https://openairdocs.org/model/cessna-310p): 61 registered aircraft (airframe model) - [Cessna 310I](https://openairdocs.org/model/cessna-310i): 60 registered aircraft (airframe model) - [Cessna 310J](https://openairdocs.org/model/cessna-310j): 59 registered aircraft (airframe model) - [Cessna 310C](https://openairdocs.org/model/cessna-310c): 58 registered aircraft (airframe model) - [Cessna 310D](https://openairdocs.org/model/cessna-310d): 56 registered aircraft (airframe model) - [Cessna 310N](https://openairdocs.org/model/cessna-310n): 55 registered aircraft (airframe model) - [Cessna 402B](https://openairdocs.org/model/cessna-402b): 49 registered aircraft (airframe model) - [Cessna 310B](https://openairdocs.org/model/cessna-310b): 45 registered aircraft (airframe model) - [Cessna 310F](https://openairdocs.org/model/cessna-310f): 41 registered aircraft (airframe model) - [Cessna 310G](https://openairdocs.org/model/cessna-310g): 41 registered aircraft (airframe model) - [Cessna 310H](https://openairdocs.org/model/cessna-310h): 33 registered aircraft (airframe model) - [Cessna 320D](https://openairdocs.org/model/cessna-320d): 30 registered aircraft (airframe model) - [Cessna 421](https://openairdocs.org/model/cessna-421): 28 registered aircraft (airframe model) - [Cessna 320E](https://openairdocs.org/model/cessna-320e): 27 registered aircraft (airframe model) - [Cessna 335](https://openairdocs.org/model/cessna-335): 26 registered aircraft (airframe model) - [Cessna 320C](https://openairdocs.org/model/cessna-320c): 23 registered aircraft (airframe model) - [Cessna 320B](https://openairdocs.org/model/cessna-320b): 21 registered aircraft (airframe model) - [Cessna 401](https://openairdocs.org/model/cessna-401): 21 registered aircraft (airframe model) - [Cessna 421A](https://openairdocs.org/model/cessna-421a): 20 registered aircraft (airframe model) - [Cessna 320](https://openairdocs.org/model/cessna-320): 17 registered aircraft (airframe model) - [Cessna 401A](https://openairdocs.org/model/cessna-401a): 15 registered aircraft (airframe model) - [Cessna 401B](https://openairdocs.org/model/cessna-401b): 15 registered aircraft (airframe model) - [Cessna 310A](https://openairdocs.org/model/cessna-310a): 14 registered aircraft (airframe model) - [Cessna 320F](https://openairdocs.org/model/cessna-320f): 12 registered aircraft (airframe model) - [Cessna 402](https://openairdocs.org/model/cessna-402): 7 registered aircraft (airframe model) - [Cessna 320A](https://openairdocs.org/model/cessna-320a): 6 registered aircraft (airframe model) - [Cessna 411](https://openairdocs.org/model/cessna-411): 6 registered aircraft (airframe model) - [Cessna 411A](https://openairdocs.org/model/cessna-411a): 4 registered aircraft (airframe model) - [Cessna 402A](https://openairdocs.org/model/cessna-402a): 3 registered aircraft (airframe model) - [Cessna 320-1](https://openairdocs.org/model/cessna-320-1): 1 registered aircraft (airframe model) - [Cessna 310-J1](https://openairdocs.org/model/cessna-310-j1): 0 registered aircraft (airframe model) --- 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.