# AD 78-12-09: Crankshaft Gear Assembly - Type: Airworthiness directive - Status: Current - Products: Lycoming Engines O-320-H1AD, O-320-H1BD, O-320-H2AD, O-320-H2BD, O-320-H3AD and O-320-H3BD - Effective: February 20, 1979 - Superseded by: Nothing supersedes this AD - Product type: Engine - Amendment: 39-3414 - Registered aircraft: 27,398 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/41D8FFD39D3CB3C186256E1200477209.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/78-12-09 ## The airworthiness directive 78-12-09 AVCO LYCOMING: Amendment 39-3238 as amended by Amendment 39-3414. Applies to O-320-H series engines with the following serial numbers, unless already accomplished. L-103-76, L-104-76, L-272-76, L-283-76, L-288-76, L-290-76, L-336-76, L-337-76, L-341-76, L-404-76, L-431-76, L-468-76, L-469-76, L-471-76, L-494-76, L-548-76, L-589-76, L-590-76, L-592-76, L-650-76, L-684-76, L-689-76, L-698-76, L-736-76, L-737-76, L-738-76, L-743-76, L-754-76, L-763-76, L-768-76, L-769-76, L-772-76, L-774-76, L-777-76, L-778-76, L-802-76, L-824-76, L-834-76, L-846-76, L-903-76, L-904-76, L-929-76, L-940-76, L-945-76, L-948-76, L-949-76, L-1054-76, L-1115-76, L-1119-76, L-1122- 76 THROUGH L-1129-76, L-1131-76 THROUGH L-1134-76, L-1144-76, L-1156-76, L-1181-76, L-1186- 76, L-1191-76, L-1200-76, L-1205-76, L-1207-76, L-1237-76, L-1255-76, L-1304-76, L-1305-76, L-1352-76, L-1354-76, L-1374-76, L-1375-76, L-1379-76, L-1460-76, L-1476-76, L-1489-76, L-1492-76, L-1513-76, L-1568-76, L-1577-76, L-1626-76, L-1630-76, L-1639-76, L-1644-76, L-1657-76, L-1658-76, L-1665-76, L-1668-76, L-1678-76, L-1679-76, L-1687-76, L-1693-76, L-1694-76, L-1697-76, L-1795-76, L-1796-76, L-1824-76, L-1825-76, L-1826-76, L-1870-76, L-1885-76, L-1934-76, L-2002-76, L-2007-76, L-2016-76, L-2025-76 THROUGH L-2032-76, L-2041-76, L-2047-76, L-2065-76 THROUGH L-2068-76, L-2071-76 THROUGH L-2077-76, L-2115-76, L-2148-76, L-2157-76, L-2159-76 THROUGH L-2163-76, L-2165-76, L-2167-76, L-2168-76, L-2171-76, L-2174-76 THROUGH L-2182-76, L-2189-76, L-2190-76, L-2191-76, L-2192-76, L-2198-76, L-2260-76, L-2293-76, L-2294-76, L-2308-76, L-2338-76, L-2339-76, L-2340-76, L-2343-76, L-2344-76, L-2350-76, L-2365-76, L-2556-76, L-2596-76, L-2635-76, L-2636-76, L-2637-76, L-2644-76, L-2666-76, L-2697-76, L-2728-76, L-2731-76, L-2758-76, L-2762-76, L-2763-76, L-2774-76, L-2777-76, L-2782-76, L-2784-76, L-2790-76, L-2816-76, L-2832-76, L-2837-76, L-2842-76, L-2843-76, L-2845-76, L-2857-76, L-2908-76, L-2914-76, L-2921-76, L-2922-76, L-2924-76, L-2930-76, L-2932-76 THROUGH L-2938-76, L-2942-76, L-2947-76, L-2948-76, L-2962-76, L-2963-76, L-2966-76, L-2975-76, L-2980-76, L-2985-76, L-2987-76, L-2988-76, L-2989-76, L-2992-76, L-2999-76, L-3004-76, L-3010-76, L-3016-76, L-3034-76, L-3035-76, L-3041-76, L-3047-76, L-3063-76, L-3067-76, L-3068-76, L-3155-76, L-3170-76, L-3172-76, L-3240-76, L-3262-76, L-3288-76, L-3289-76, L-3291-76, L-3292-76, L-3293-76, L-3295-76, L-3296-76, L-3308-76, L-3313-76, L-3319-76, L-3384-76, L-3395-76 THROUGH L-3400-76, L-3402-76, L-3403-76, L-3404-76, L-3406-76, L-3411-76, L-3412-76, L-3413-76, L-3414-76, L-3428-76, L-3467-76, L-3551-76, RL-114-76, RL-124-76, RL-133-76, RL-162-76, RL-176-76, RL-186-76, RL-205-76, RL-249-76, RL-254-76, RL-328-76, RL-332-76, RL-351-76, RL-367-76, RL-384-76, RL-408-76, RL-416-76, RL- 418-76, RL-419-76, RL-435-76, RL-442-76, RL-443-76, RL-477-76, RL-510-76, RL-543-76, RL-550-76, RL-612-76, RL-652-76, RL-673-76, RL-695-76, RL-832-76, RL-1022-76, RL-1082-76, RL-1173-76, RL-1218-76, RL-214-76. Compliance required before further flight except that the aircraft may be flown in accordance with FAR 21.197 to a location where this AD may be accomplished. a. To prevent possible crankshaft gear failure, remove and replace the crankshaft assembly and install crankshaft assembly P/N LW-15917 in accordance with AVCO Lycoming Service Bulletin No. 422, dated March 24, 1978, or FAA approved equivalent. b. Equivalent methods of compliance must be approved by the Chief, Engineering and Manufacturing Branch, FAA Eastern Region. Amendment 39-3238 was effective June 20, 1978. This Amendment 39-3414 is effective February 20, 1979. ## Affected data sheets (1) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS E-274](https://openairdocs.org/tcds/E-274): Lycoming Engines; names 6 of 60 models: O-320-H3BD, O-320-H2BD, O-320-H2AD, O-320-H3AD, O-320-H1BD, O-320-H1AD ## 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: 27,398 (0 by airframe model, 27,398 by engine model) - Makers: Piper 11,632, Cessna 9,982, Grumman American Avn. 605, Bellanca 588, Beech 398, Champion 295, Robinson Helicopter 289, American Champion 250, American 116, Gulfstream American 95 Models with the most aircraft: - [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series): 27,057 aircraft (engine model) - [Lycoming O-320 series](https://openairdocs.org/engine/lycoming-o-320-series): 256 aircraft (engine model) - [Lycoming O-320-H2AD](https://openairdocs.org/engine/lycoming-o-320-h2ad): 83 aircraft (engine model) - [Aerotec O-320 series](https://openairdocs.org/engine/aerotec-o-320-series): 2 aircraft (engine model) All 4 models: https://openairdocs.org/ad/78-12-09/models.md Every aircraft: https://openairdocs.org/ad/78-12-09/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.