# AD 73-23-01: Piston Pin Assembly - Type: Airworthiness directive - Status: Current - Products: Lycoming Engines AIO-360-A1A, AIO-360-A1B, AIO-360-A2A, AIO-360-A2B, AIO-360-B1B, GO-480-G1D6, HIO-360-A1A, HIO-360-B1A, HIO-360-B1B, HIO-360-C1A, HIO-360-C1B, HIO-360-D1A and 206 more - Effective: January 13, 1977 - Superseded by: Nothing supersedes this AD - Product type: Engine - Amendment: 39-2804 - Registered aircraft: 71,254 may be affected, by airframe or engine model (OpenAirDocs) - FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/534E4B43F97807DB86256E12004775A2.0001 - DRS record last changed: May 30, 2024 - Page: https://openairdocs.org/ad/73-23-01 ## The airworthiness directive 73-23-01 AVCO LYCOMING: Amendment 39-1738 as amended by Amendment 39-1825, 39-1984 and 39-2188 is further amended by Amendment 39-2804. Applies to all Lycoming series engines and all engines overhauled by Lycoming (also known as remanufactured) listed below and in Lycoming Service Bulletin No. 367F and in Supplement No. 1 for Lycoming Service Bulletin No. 367F. O-320 Series L-6798-39A thru L-6815-39A IO-320 Series L-4952-55 O-360 Series L-17389-36A thru L-17408-36A, L-17410-36A thru L-17427-36A, L-17429-36A thru L-17452-36A, L-17454-36A thru L-17479-36A, L-17481-36A thru L-17495-36A, L-17497-36A thru L-17500-36A, L-17503-36A thru L-17505-36A, L-17516-36A thru L-17518-36A RL-523-36A, RL-2030-36A, RL-3933-36A, RL-7173-36A, RL-11169-36A, RL-16937-36A IO & HIO-360 Series L-9409-51A, L-9410-51A, L-9415-51A thru L-9417-51A, L-9419-51A thru L-9427-51A, L-9438-51A thru L-9453-51A, L-9455-51A, L-9457-51A thru L-9498-51A, L-9500-51A thru L-9517-51A, L-9519-51A thru L-9564-51A, L-9566-51A thru L-9616-51A, L-9618-51A, L-9620-51A thru L-9640-51A, L-9642-51A thru L-9651-51A, L-9653-51A thru L-9713-51A, L-9715-51A, L-9716-51A, L-9718-51A thru L-9768-51A, L-9770-51A thru L-9774-51A, L-9776-51A thru L-9826-51A, L-9828-51A thru 9848-51A, L-9850-51A thru L-9930-51A, L-9932-51A thru L-9962-51A, L-9964-51A thru L-9995-51A, L-9997-51A thru L-10090-51A, L-10092-51A thru L-10113-51A, L-10115-51A thru L-10249-51A, L-10257-51A thru L-10261-51A, L-10263-51A thru L-10273-51A, L-10279-51A thru L-10281-51A, L-10284-51A thru L-10290-51A RL-191-51A, RL-591-51A, RL-595-51A, RL-702-51A, RL-776-51A, RL-778-51A, RL-955-51A, RL-993-51A, RL-1267-51A, RL-1272-51A, RL-1435-51A, RL-1481-51A, RL-1515-51A, RL-1642-51A, RL-1769-51A, RL-1845-51A, RL-1847-51A, RL-2143-51A, RL-2227-51A, RL-2249-51A, RL-2464-51A, RL-2476-51A, RL-2508-51A, RL-2562-51A, RL-2629-51A, RL-2672-51A, RL-2923-51A, RL-3048-51A, RL-3113-51A, RL-3195-51A, RL-3235-51A, RL-3318-51A, RL-3344-51A, RL-3392-51A, RL-3427-51A, RL-3464-51A, RL-3540-51A, RL-3573-51A, RL-3738-51A, RL-3832-51A, RL-3868-51A, RL-3974-51A, RL-4787-51A, RL-4960-51A, RL-5082-51A, RL-5085-51A, RL-5652-51A, RL-5685-51A, RL-5751-51A, RL-5824-51A, RL-6331-51A, RL-6345-51A, RL-6350-51A, RL-6417-51A, RL-6469-51A, RL-6623-51A, RL-6652-51A, RL-6693-51A, RL-6724-51A, RL-6744-51A, RL-6950-51A, RL-7043-51A, RL-7201-51A, RL-7357-51A, RL-7422-51A, RL-7475-51A, RL-7806-51A, RL-7852-51A, RL-7886-51A, RL-8000-51A, RL-8354-51A, RL-8872-51A, RL-9611-51A, RL-9812-51A AIO-360 Series L-165-63A thru L-171-63A TIO-360 Series L-112-64A thru L-115-64A LIO-360 Series L-440-67A thru L-480-67A, L-487-67A thru L-512-67A, L-514-67A thru L-537-67A, L-545-67A thru L-591-67A, L-593-67A thru L-632-67A, L-634-67A thru L-648-67A, L-650-67A thru L-655-67A, L-660-67A GO-480-G1D6 Series RL-288-37, RL-482-37 IGSO-480-A1E6 Series RL-829-44, RL-1258-44, RL-1508-44, RL-1509-44, RL-1518-44, RL-1586-44 IGO-540 Series L-320-49 VO-540 Series L-2280-43, L-2281-43 RL-343-43, RL-376-43, RL-456-43, RL-485-43, RL-522-43, RL-564-43, RL-691-43, RL-694-43, RL-846-43, RL-849-43, RL-1125-43, RL-1148-43, RL-1186-43, RL-1333-43, RL-1452-43, RL-1571-43, RL-1700-43, RL-1731-43, RL-1828-43, RL-1900-43, RL-1913-43, RL-1929-43, RL-1931-43, RL-2041-43, RL-2125-43, RL-2142-43, RL-2208-43, RL-2224-43, RL-2245-43, RL-2269-43, RL-2275-43 thru RL-2279-43 O-540-A1C5, -A1D5, -B1A5, -B2B5, -B4B5, -B2C5, -E4A5, -E4B5, -E4C5, G1A5 Series L-15062-40, L-15063-40, L-15108-40, L-15117-40, L-15132-40, L-15133-40, L-15161-40, L-15221-40, L-15222-40, L-15225-40 thru L-15227-40, L-15242-40 thru L-15249-40, L-15297-40, L-15300-40, L-15304-40 thru L-15320-40, L-15322-40 thru L-15367-40, L-15372-40 RL-1040-40, RL-1207-40, RL-3330-40, RL-6768-40, RL-7670-40, RL-9416-40, RL-10859-40, RL-11312-40, RL-11377-40, RL-11420-40, RL-11862-40, RL-13058-40, RL-13637-40, RL-14194-40 IO-540-A1A5, -B1A5, -C1A5, -C4B5, -D4A5, -E1A5, -E1B5, -G1D5, J4A5, -K1A5, -K1B5, -K1C5, -K1E5, -K1E5D Series L-10118-48 thru L-10122-48, L-10124-48 thru L-10127-48, L-10144-48, L-10145-48, L-10209-48, L-10213-48, L-10221-48 thru L-10260-48, L-10263-48 thru L-10267-48, L-10303-48, L-10304-48, L-10306-48 thru L-10308-48, L-10317-48 thru L-10320-48, L-10398-48, L-10459-48, L-10487-48 thru L-10546-48, L-10548-48 thru L-10562-48, L-10564-48 thru L-10569-48, L-10571-48 thru L-10584-48 RL-113-48, RL-622-48, RL-918-48, RL-1170-48, RL-1606-48, RL-1640-48, RL-2015-48, RL-2050-48, RL-2210-48, RL-2271-48, RL-2276-48, RL-3610-48, RL-3614-48, RL-3732-48, RL-4057-48, RL-4103-48, RL-4506-48, RL-5778-48, RL-7116-48 TIO-540-A2B, -A2C, -C1A, TIO-540-J2BD Series L-2412-61 thru L-2414-61, L-2416-61 thru L-2419-61, L-2489-61 thru L-2498-61, L-2501-61 thru L-2503-61, L-2550-61, L-2557-61, L-2562-61, L-2566-61, L-2567-61, L-2572-61 thru L-2583-61, L-2585-61 thru L-2588-61, L-2590-61, L-2591-61, L-2595-61 thru L-2597-61 RL-122-61, RL-226-61, RL-759-61, RL-771-61, RL-1263-61,RL-1268-61, RL-1346-61, RL-1488-61, RL-1679-61, RL-1683-61, RL-2189-61 LIO-540 Series L-102-68, L-105-68, L-109-68, L-113-68 thru L-117-68, L-125-68, L-128-68 thru L-130-68, L-147-68 thru L-152-68, L-154-68, L-155-68 RL-106-68 IGSO-540 Series L-3060-50, L-3061-50, L-3070-50, L-3071-50, L-3074-50, L-3085-50 thru L-3087-50, L-3090-50, L-3093-50, L-3094-50 RL-315-50, RL-518-50, RL-528-50, RL-821-50, RL-1014-50, RL-1100-50, RL-1151-50, RL-1174-50, RL-1216-50, RL-1517-50, RL-1558-50, RL-1591-50, RL-1682-50, RL-1694-50, RL-1700-50, RL-1773-50, RL-1788-50, RL-1821-50, RL-2003-50, RL-2157-50, RL-2187-50, RL-2385-50, RL-2479-50, RL-2543-50, RL-2604-50, RL-2907-50 TIO-541 Series L-866-59 thru L-873-59 TIGO-541 Series L-343-62 thru L-352-62 RL-161-62 IO-720-A, -B and -C Series L-505-54, L-506-54, L-508-54 thru L-529-54, L-532-54 thru L-538-54, L-540-54, L-541-54, L-546-54 thru L-549-54, L-551-54 thru L-554-54 Compliance required within 50 hours in service after the effective date of this AD, unless already accomplished. To prevent piston pin failures resulting from grinding cracks which occurred during manufacture, comply with Lycoming Service Bulletin No. 367F or equivalent procedure approved by Chief, Engineering and Manufacturing Branch, FAA, Eastern Region. The manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). All persons affected by this directive who have not already received these documents from the manufacturer, may obtain copies upon request to Avco Lycoming Division, Service Department, Williamsport Pennsylvania 17701. These documents may also be examined at the Engineering and Manufacturing Branch, Federal Aviation Administration, Eastern Region, Federal Building, John F. Kennedy International Airport, Jamaica, New York 11430. A historical file on this AD which includes the incorporated material in full is maintained by the FAA at its Eastern Region Headquarters. Amendment 39-1738 was effective November 1, 1973. Amendment 39-1825 was effective May 1, 1974. Amendment 39-1984 was effective October 10, 1974. Amendment 39-2188 was effective April 30, 1975. This amendment 39-2804 is effective January 13, 1977. ## Affected data sheets (16) (OpenAirDocs) The type certificate data sheets whose models the AD names. - [TCDS E-274](https://openairdocs.org/tcds/E-274): Lycoming Engines; names 46 of 60 models: O-320-E2G, O-320-C2B, O-320-E2B, O-320-E2C, O-320-B3B, O-320-C3A, O-320-C2A, O-320-E3H… - [TCDS 1E10](https://openairdocs.org/tcds/1E10): Lycoming Engines; names 41 of 89 models: IO-360-C1D6, HIO-360-B1B, IO-360-B2F6, HIO-360-C1B, AIO-360-A1B, IO-360-B2E, IO-360-B1F, AIO-360-A2A… - [TCDS E-286](https://openairdocs.org/tcds/E-286): Lycoming Engines; names 36 of 72 models: O-360-C1C, O-360-C1A, O-360-B1A, O-360-A1A, O-360-A1G6, O-360-A3D, O-360-A1F6D, O-360-A1LD… - [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 1E12](https://openairdocs.org/tcds/1E12): Lycoming Engines; names 13 of 32 models: IO-320-B1C, IO-320-B1D, IO-320-B2A, IO-320-E2B, IO-320-E1A, IO-320-C1A, IO-320-B1B, IO-320-D1B… - [TCDS 1E4](https://openairdocs.org/tcds/1E4): Lycoming Engines; names 13 of 81 models: IO-540-A1A5, IO-540-C4B5, IO-540-K1B5, IO-540-K1E5, IO-540-K1C5, IO-540-G1D5, IO-540-E1A5, IO-540-D4A5… - [TCDS E-295](https://openairdocs.org/tcds/E-295): Lycoming Engines; names 10 of 47 models: O-540-B2C5, O-540-B2B5, O-540-A1D5, O-540-E4C5, O-540-G1A5, O-540-B4B5, O-540-E4A5, O-540-B1A5… - [TCDS 1E7](https://openairdocs.org/tcds/1E7): Lycoming Engines; names 7 of 8 models: IGSO-540-A1F, IGSO-540-B1A, IGSO-540-A1C, IGSO-540-A1A, IGSO-540-B1C, IGSO-540-A1D, IGSO-540-A1E - [TCDS 1E11](https://openairdocs.org/tcds/1E11): Lycoming Engines; names 6 of 6 models: IGO-540-B1B, IGO-540-B1A, IGO-540-B1C, IGO-540-A1A, IGO-540-A1C, IGO-540-A1B - [TCDS 1E15](https://openairdocs.org/tcds/1E15): Textron Lycoming Subsidiary of Textron Inc.; names 5 of 12 models: IO-720-B1A, IO-720-A1A, IO-720-B1B, IO-720-A1B, IO-720-D1B - [TCDS E10EA](https://openairdocs.org/tcds/E10EA): Lycoming Engines; names 5 of 5 models: TIO-541-E1A4, TIO-541-E1B4, TIO-541-E1C4, TIO-541-A1A, TIO-541-E1D4 - [TCDS E19EA](https://openairdocs.org/tcds/E19EA): Lycoming Engines; names 5 of 6 models: TIGO-541-C1A, TIGO-541-G1AD, TIGO-541-E1A, TIGO-541-B1A, TIGO-541-D1A - [TCDS E14EA](https://openairdocs.org/tcds/E14EA): Lycoming Engines; names 4 of 40 models: TIO-540-C1A, TIO-540-J2BD, TIO-540-A2C, TIO-540-A2B - [TCDS E16EA](https://openairdocs.org/tcds/E16EA): Lycoming Engines; names 4 of 4 models: TIO-360-A1B, TIO-360-A1A, TIO-360-C1A6D, TIO-360-A3B6 - [TCDS E-275](https://openairdocs.org/tcds/E-275): Lycoming Engines; names 1 of 33 models: GO-480-G1D6 - [TCDS E-284](https://openairdocs.org/tcds/E-284): Lycoming Engines; names 1 of 23 models: IGSO-480-A1E6 ## 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: 71,254 (0 by airframe model, 71,254 by engine model) - Makers: Piper 31,082, Cessna 16,015, Mooney 3,769, Beech 2,039, Bellanca 1,239, Grumman American Avn. 1,197, Robinson Helicopter 1,000, Maule 678, Aviat 609, Aero Commander 447 Models with the most aircraft: - [Lycoming 0-320 series](https://openairdocs.org/engine/lycoming-0-320-series): 27,057 aircraft (engine model) - [Lycoming O&VO-360 series](https://openairdocs.org/engine/lycoming-o-vo-360-series): 11,931 aircraft (engine model) - [Lycoming I0360 series](https://openairdocs.org/engine/lycoming-i0360-series): 6,174 aircraft (engine model) - [Lycoming 0-540 series](https://openairdocs.org/engine/lycoming-0-540-series): 5,228 aircraft (engine model) - [Lycoming TI0-540 series](https://openairdocs.org/engine/lycoming-ti0-540-series): 4,886 aircraft (engine model) - [Lycoming IO-540 series](https://openairdocs.org/engine/lycoming-io-540-series): 4,219 aircraft (engine model) - [Lycoming IO-320 series](https://openairdocs.org/engine/lycoming-io-320-series): 1,707 aircraft (engine model) - [Lycoming O-360 series](https://openairdocs.org/engine/lycoming-o-360-series): 1,023 aircraft (engine model) - [Lycoming IO-360-B4A](https://openairdocs.org/engine/lycoming-io-360-b4a): 985 aircraft (engine model) - [Lycoming 0-360-A1D](https://openairdocs.org/engine/lycoming-0-360-a1d): 968 aircraft (engine model) - [Lycoming IO-360-A1B6D](https://openairdocs.org/engine/lycoming-io-360-a1b6d): 844 aircraft (engine model) - [Lycoming O-360-A1A](https://openairdocs.org/engine/lycoming-o-360-a1a): 601 aircraft (engine model) - [Lycoming HIO-360 series](https://openairdocs.org/engine/lycoming-hio-360-series): 336 aircraft (engine model) - [Lycoming TI0-541 series](https://openairdocs.org/engine/lycoming-ti0-541-series): 271 aircraft (engine model) - [Lycoming O-320-E2D](https://openairdocs.org/engine/lycoming-o-320-e2d): 258 aircraft (engine model) - [Lycoming O-320 series](https://openairdocs.org/engine/lycoming-o-320-series): 256 aircraft (engine model) - [Lycoming GO-480 series](https://openairdocs.org/engine/lycoming-go-480-series): 246 aircraft (engine model) - [Lycoming IO-540-D4A5](https://openairdocs.org/engine/lycoming-io-540-d4a5): 237 aircraft (engine model) - [Lycoming IO-360 series](https://openairdocs.org/engine/lycoming-io-360-series): 217 aircraft (engine model) - [Lycoming IO-360-A1A](https://openairdocs.org/engine/lycoming-io-360-a1a): 196 aircraft (engine model) All 182 models: https://openairdocs.org/ad/73-23-01/models.md Every aircraft: https://openairdocs.org/ad/73-23-01/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.