# AD 80-04-04 R1: Crankshaft Flange Bolts - Type: Airworthiness directive - Status: Current - Products: Lycoming Engines IVO-540-A1A, TIVO-540-A2A, TVO-435-A1A, TVO-435-B1A, TVO-435-B1B, TVO-435-C1A, TVO-435-D1A, TVO-435-D1B, TVO-435-E1A, TVO-435-F1A, TVO-435-G1A, TVO-435-G1B and 29 more - Effective: August 18, 1980 - Superseded by: Nothing supersedes this AD - Product type: Engine - Amendment: 39-3881 - Registered aircraft: 341 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/A80C6D42494EF01386256841005AD8DF.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/80-04-04-R1 ## The airworthiness directive 80-04-04 R1 AVCO LYCOMING: Amendment 39-3691 as amended by Amendment 39-3881. Applies to all VO and TVO-435 series engines and to all VO, IVO, TVO and TIVO-540 series engines. To prevent possible failure of the crankshaft flange bolts perform the following, unless already accomplished: (a) Within the next 50 hours in service after effective date of this AD, engines that have accumulated 550 hours' or more time in service since new or overhaul must have the engine crankshaft flange to transmission drive coupling attaching bolt nuts checked for 15 ft.-lbs. torque measured in the tightening direction. If the torque on any attaching bolt nut is less than 15 ft.-lbs., the engine crankshaft flange and the helicopter transmission drive coupling flange must be inspected for cracks, fretting, galling, or for any metal transfer from one surface to its mating surface. Remove from service any crankshaft or drive coupling which shows such deficiencies. Prior to returning the engine to service accomplish the following: (1) Remove and discard all flange bolts. Measure all bolt holes in the crankshaft flange and repair if necessary in accordance with the requirements of AVCO Lycoming Service Instruction No. 1209B or equivalent procedure approved by Chief, Engineering & Manufacturing Branch, FAA Eastern Region. (2) Install replacement bolts in accordance with Avco Lycoming Service Instruction No. 1209B paragraph 5 or equivalent procedure approved by Chief, Engineering & Manufacturing Branch, FAA Eastern Region. Those engines which showed no such deficiencies or whose attaching bolt nut torques measured 15 ft.-lbs. may be returned to service, but the torque of the crankshaft flange attaching bolt nuts must be measured every 600 hours in service thereafter or until compliance with paragraphs (a)(1) and (a)(2) of this AD is accomplished. Amendment 39-3691 was effective February 8, 1980. This amendment 39-3881 is effective August 18, 1980. ## Affected data sheets (5) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS E-304](https://openairdocs.org/tcds/E-304): Lycoming Engines; names 21 of 21 models: VO-540-B2G, VO-540-B2A, VO-540-B2D, VO-540-B1B3, VO-540-B1D, VO-540-B1C, VO-540-B1A, VO-540-A2A… - [TCDS 1E13](https://openairdocs.org/tcds/1E13): Lycoming Engines; names 10 of 11 models: TVO-435-D1B, TVO-435-A1A, TVO-435-E1A, TVO-435-C1A, TVO-435-B1B, TVO-435-B1A (O-435-25A), TVO-435-G1B, TVO-435-D1A… - [TCDS E-279](https://openairdocs.org/tcds/E-279): Lycoming Engines; names 7 of 7 models: VO-435-A1A (O-435-21), VO-435-A1F, VO-435-A1C (O-435-23; -23A; -23B; -23C), VO-435-A1E, VO-435-A1D (O-435-6A), VO-435-B1A, VO-435-A1B (O-435-6) - [TCDS 1E14](https://openairdocs.org/tcds/1E14): Lycoming Engines; names 2 of 2 models: TIVO-540-A2A, TVO-540-A1A - [TCDS E11EA](https://openairdocs.org/tcds/E11EA): Lycoming Engines; names 1 of 1 models: IVO-540-A1A ## 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: 341 (0 by airframe model, 341 by engine model) - Makers: Bell 220, Hiller 75, Continental Copters 11, Texas Helicopter 10, Piper 6, Brantly 2, Hiller-Osborn 2, Anthony L R/Anthony D J 1, Bell-Carson 1, Bell-Continental Copters 1 Models with the most aircraft: - [Lycoming VO-435 series](https://openairdocs.org/engine/lycoming-vo-435-series): 191 aircraft (engine model) - [Lycoming VO-540 series](https://openairdocs.org/engine/lycoming-vo-540-series): 110 aircraft (engine model) - [Lycoming VO-435-A1F](https://openairdocs.org/engine/lycoming-vo-435-a1f): 15 aircraft (engine model) - [Lycoming VO-435-B1A](https://openairdocs.org/engine/lycoming-vo-435-b1a): 6 aircraft (engine model) - [Lycoming VO-540-C2A](https://openairdocs.org/engine/lycoming-vo-540-c2a): 6 aircraft (engine model) - [Lycoming VO-435-A1D](https://openairdocs.org/engine/lycoming-vo-435-a1d): 3 aircraft (engine model) - [Lycoming VO-540-B1B3](https://openairdocs.org/engine/lycoming-vo-540-b1b3): 3 aircraft (engine model) - [Lycoming TVO-435-B1A](https://openairdocs.org/engine/lycoming-tvo-435-b1a): 2 aircraft (engine model) - [Lycoming TVO-435-D1A](https://openairdocs.org/engine/lycoming-tvo-435-d1a): 2 aircraft (engine model) - [Lycoming TVO-435-A1A](https://openairdocs.org/engine/lycoming-tvo-435-a1a): 1 aircraft (engine model) - [Lycoming TVO-435-F1A](https://openairdocs.org/engine/lycoming-tvo-435-f1a): 1 aircraft (engine model) - [Lycoming TVO-435-G1A](https://openairdocs.org/engine/lycoming-tvo-435-g1a): 1 aircraft (engine model) All 13 models: https://openairdocs.org/ad/80-04-04-R1/models.md Every aircraft: https://openairdocs.org/ad/80-04-04-R1/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.