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FAA orders · airworthiness directive · current

73-23-01: Piston Pin Assembly

FAA order 73-23-01 is an airworthiness directive in force since January 13, 1977. The FAA's subject line: Piston Pin Assembly. It names the Lycoming GO-480-G1D6, Lycoming HIO-360-A1A, Lycoming HIO-360-B1A, Lycoming HIO-360-B1B, Lycoming HIO-360-C1A, Lycoming HIO-360-C1B, Lycoming HIO-360-D1A, Lycoming IGO-540-A1C, Lycoming IGO-540-B1A, Lycoming IGSO-480-A1E6, Lycoming IGSO-540-B1A, Lycoming IO-320-A1A, Lycoming IO-320-B1A, Lycoming IO-320-B1C, Lycoming IO-320-B2A, Lycoming IO-320-C1A, Lycoming IO-320-D1A, Lycoming IO-320-D1B, Lycoming IO-320-E1A, Lycoming IO-320-E2A, Lycoming IO-320-E2B, Lycoming IO-320 series, Lycoming IO-360-A1A, Lycoming IO-360-A1B, Lycoming IO-360-A1B6, Lycoming IO-360-A1B6D, Lycoming IO-360-A1D, Lycoming IO-360-A1D6, Lycoming IO-360-A2B, Lycoming IO-360-B1A, Lycoming IO-360-B1B, Lycoming IO-360-B1C, Lycoming IO-360-B1D, Lycoming IO-360-B1E, Lycoming IO-360-B1F, Lycoming IO-360-B1F6, Lycoming IO-360-B2E, Lycoming IO-360-B2F, Lycoming IO-360-B4A, Lycoming IO-360-C1A, Lycoming IO-360-C1C, Lycoming IO-360-C1D6, Lycoming IO-360-C1F, Lycoming IO-360-D1A, Lycoming IO-360-E1A, Lycoming IO-360-F1A, Lycoming IO-360 series, Lycoming IO-540-A1A5, Lycoming IO-540-B1A5, Lycoming IO-540-C4B5, Lycoming IO-540-D4A5, Lycoming IO-540-E1A5, Lycoming IO-540-E1B5, Lycoming IO-540-G1D5, Lycoming IO-540-J4A5, Lycoming IO-540-K1A5, Lycoming IO-540-K1B5, Lycoming IO-540-K1C5, Lycoming IO-540-K1E5, Lycoming IO-540 series, Lycoming IO-720, Lycoming IO-720-A1B, Lycoming LIO-360-C1E6, Lycoming O-320-A1A, Lycoming O-320-A1B, Lycoming O-320-A2A, Lycoming O-320-A2B, Lycoming O-320-A2C, Lycoming O-320-A2D, Lycoming O-320-A3A, Lycoming O-320-A3B, Lycoming O-320-A3C, Lycoming O-320-B1A, Lycoming O-320-B1B, Lycoming O-320-B2A, Lycoming O-320-B2B, Lycoming O-320-B2C, Lycoming O-320-B3B, Lycoming O-320-C1A, Lycoming O-320-C2A, Lycoming O-320-C3B, Lycoming O-320-D1A, Lycoming O-320-D1F, Lycoming O-320-D2A, Lycoming O-320-D2B, Lycoming O-320-D2C, Lycoming O-320-E1A, Lycoming O-320-E1F, Lycoming O-320-E2A, Lycoming O-320-E2B, Lycoming O-320-E2C, Lycoming O-320-E2D, Lycoming O-320-E2G, Lycoming O-320-E3D, Lycoming O-320-E3H, Lycoming O-320 series, Lycoming O-360-A1A, Lycoming O-360-A1D, Lycoming O-360-A1F, Lycoming O-360-A1F6, Lycoming O-360-A1F6D, Lycoming O-360-A1G, Lycoming O-360-A1G6, Lycoming O-360-A1H, Lycoming O-360-A1LD, Lycoming O-360-A2A, Lycoming O-360-A2D, Lycoming O-360-A2F, Lycoming O-360-A2G, Lycoming O-360-A3A, Lycoming O-360-A4A, Lycoming O-360-A4G, Lycoming O-360-B1A, Lycoming O-360-B1B, Lycoming O-360-B2A, Lycoming O-360-C1A, Lycoming O-360-C2A, Lycoming O-360-C2C, Lycoming O-360-C2D, Lycoming O-360-D1A, Lycoming O-360-D2A, Lycoming O-360 series, Lycoming O-540-A1C5, Lycoming O-540-A1D5, Lycoming O-540-B1A5, Lycoming O-540-B2B5, Lycoming O-540-B2C5, Lycoming O-540-B4B5, Lycoming O-540-E4A5, Lycoming O-540-E4B5, Lycoming O-540-E4C5, Lycoming O-540-G1A5, Lycoming TIGO-541-E1A, Lycoming TIGO-541 series, Lycoming TIO-360-C1A6D, Lycoming TIO-360 series, Lycoming TIO-540-A2B, Lycoming TIO-540-A2C, Lycoming TIO-540-C1A, Lycoming TIO-540-J2BD, Lycoming TIO-541-A1A, Lycoming TIO-541-E1C4, Lycoming TIO-541 series, Lycoming VO-540-B1B3, Lycoming VO-540-C2A, Lycoming VO-540 series engines: about 50,372 aircraft on the U.S. register today across them, though an order usually covers particular versions or serial numbers rather than every one. System: engine.

What it applies to as the FAA lists it

Kind of product
Engine
Makes
Lycoming Engines; Textron Lycoming, AVCO Corporation
Models
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, IGO-540-A1A, IGO-540-A1B, IGO-540-A1C, IGO-540-B1A, IGO-540-B1B, IGO-540-B1C, IGSO-480-A1E6, IGSO-540-A1A, IGSO-540-A1C, IGSO-540-A1D, IGSO-540-A1E, IGSO-540-A1F, IGSO-540-B1A, IGSO-540-B1C, IO-320-A1A, IO-320-A2A, IO-320-B1A, IO-320-B1B, IO-320-B1C, IO-320-B1D, IO-320-B2A, IO-320-C1A, IO-320-D1A, IO-320-D1B, IO-320-E1A, IO-320-E2A, IO-320-E2B, IO-360-A1A, IO-360-A1B, IO-360-A1B6, IO-360-A1B6D, IO-360-A1C, IO-360-A1D, IO-360-A1D6,...
Engine series
Lycoming GO-480-G1D6 7 aircraft
Lycoming HIO-360-A1A 5 aircraft
Lycoming HIO-360-B1A 16 aircraft
Lycoming HIO-360-B1B 2 aircraft
Lycoming HIO-360-C1A 6 aircraft
Lycoming HIO-360-C1B 1 aircraft
Lycoming HIO-360-D1A 41 aircraft
Lycoming IGO-540-A1C 1 aircraft
Lycoming IGO-540-B1A 9 aircraft
Lycoming IGSO-480-A1E6 1 aircraft
Lycoming IGSO-540-B1A 48 aircraft
Lycoming IO-320-A1A 2 aircraft
Lycoming IO-320-B1A 55 aircraft
Lycoming IO-320-B1C 2 aircraft
Lycoming IO-320-B2A 1 aircraft
Lycoming IO-320-C1A 7 aircraft
Lycoming IO-320-D1A 57 aircraft
Lycoming IO-320-D1B 6 aircraft
Lycoming IO-320-E1A 3 aircraft
Lycoming IO-320-E2A 11 aircraft
Lycoming IO-320-E2B 4 aircraft
Lycoming IO-320 series 1,707 aircraft
Lycoming IO-360-A1A 195 aircraft
Lycoming IO-360-A1B 52 aircraft
Lycoming IO-360-A1B6 141 aircraft
Lycoming IO-360-A1B6D 844 aircraft
Lycoming IO-360-A1D 15 aircraft
Lycoming IO-360-A1D6 191 aircraft
Lycoming IO-360-A2B 2 aircraft
Lycoming IO-360-B1A 49 aircraft
Lycoming IO-360-B1B 67 aircraft
Lycoming IO-360-B1C 6 aircraft
Lycoming IO-360-B1D 2 aircraft
Lycoming IO-360-B1E 184 aircraft
Lycoming IO-360-B1F 8 aircraft
Lycoming IO-360-B1F6 3 aircraft
Lycoming IO-360-B2E 3 aircraft
Lycoming IO-360-B2F 1 aircraft
Lycoming IO-360-B4A 969 aircraft
Lycoming IO-360-C1A 7 aircraft
Lycoming IO-360-C1C 45 aircraft
Lycoming IO-360-C1D6 14 aircraft
Lycoming IO-360-C1F 2 aircraft
Lycoming IO-360-D1A 4 aircraft
Lycoming IO-360-E1A 3 aircraft
Lycoming IO-360-F1A 3 aircraft
Lycoming IO-360 series 8,560 aircraft
Lycoming IO-540-A1A5 16 aircraft
Lycoming IO-540-B1A5 4 aircraft
Lycoming IO-540-C4B5 179 aircraft
Lycoming IO-540-D4A5 236 aircraft
Lycoming IO-540-E1A5 4 aircraft
Lycoming IO-540-E1B5 4 aircraft
Lycoming IO-540-G1D5 26 aircraft
Lycoming IO-540-J4A5 9 aircraft
Lycoming IO-540-K1A5 44 aircraft
Lycoming IO-540-K1B5 17 aircraft
Lycoming IO-540-K1C5 1 aircraft
Lycoming IO-540-K1E5 5 aircraft
Lycoming IO-540 series 4,218 aircraft
Lycoming IO-720 119 aircraft
Lycoming IO-720-A1B 8 aircraft
Lycoming LIO-360-C1E6 6 aircraft
Lycoming O-320-A1A 20 aircraft
Lycoming O-320-A1B 2 aircraft
Lycoming O-320-A2A 9 aircraft
Lycoming O-320-A2B 180 aircraft
Lycoming O-320-A2C 1 aircraft
Lycoming O-320-A2D 13 aircraft
Lycoming O-320-A3A 5 aircraft
Lycoming O-320-A3B 12 aircraft
Lycoming O-320-A3C 1 aircraft
Lycoming O-320-B1A 17 aircraft
Lycoming O-320-B1B 3 aircraft
Lycoming O-320-B2A 11 aircraft
Lycoming O-320-B2B 92 aircraft
Lycoming O-320-B2C 55 aircraft
Lycoming O-320-B3B 22 aircraft
Lycoming O-320-C1A 1 aircraft
Lycoming O-320-C2A 2 aircraft
Lycoming O-320-C3B 1 aircraft
Lycoming O-320-D1A 116 aircraft
Lycoming O-320-D1F 7 aircraft
Lycoming O-320-D2A 72 aircraft
Lycoming O-320-D2B 18 aircraft
Lycoming O-320-D2C 1 aircraft
Lycoming O-320-E1A 3 aircraft
Lycoming O-320-E1F 5 aircraft
Lycoming O-320-E2A 98 aircraft
Lycoming O-320-E2B 4 aircraft
Lycoming O-320-E2C 11 aircraft
Lycoming O-320-E2D 257 aircraft
Lycoming O-320-E2G 32 aircraft
Lycoming O-320-E3D 65 aircraft
Lycoming O-320-E3H 2 aircraft
Lycoming O-320 series 27,316 aircraft
Lycoming O-360-A1A 600 aircraft
Lycoming O-360-A1D 1,057 aircraft
Lycoming O-360-A1F 4 aircraft
Lycoming O-360-A1F6 13 aircraft
Lycoming O-360-A1F6D 18 aircraft
Lycoming O-360-A1G 1 aircraft
Lycoming O-360-A1G6 1 aircraft
Lycoming O-360-A1H 8 aircraft
Lycoming O-360-A1LD 1 aircraft
Lycoming O-360-A2A 38 aircraft
Lycoming O-360-A2D 5 aircraft
Lycoming O-360-A2F 13 aircraft
Lycoming O-360-A2G 3 aircraft
Lycoming O-360-A3A 50 aircraft
Lycoming O-360-A4A 63 aircraft
Lycoming O-360-A4G 2 aircraft
Lycoming O-360-B1A 13 aircraft
Lycoming O-360-B1B 2 aircraft
Lycoming O-360-B2A 3 aircraft
Lycoming O-360-C1A 7 aircraft
Lycoming O-360-C2A 19 aircraft
Lycoming O-360-C2C 6 aircraft
Lycoming O-360-C2D 2 aircraft
Lycoming O-360-D1A 6 aircraft
Lycoming O-360-D2A 4 aircraft
Lycoming O-360 series 1,066 aircraft
Lycoming O-540-A1C5 4 aircraft
Lycoming O-540-A1D5 18 aircraft
Lycoming O-540-B1A5 1 aircraft
Lycoming O-540-B2B5 27 aircraft
Lycoming O-540-B2C5 13 aircraft
Lycoming O-540-B4B5 40 aircraft
Lycoming O-540-E4A5 9 aircraft
Lycoming O-540-E4B5 21 aircraft
Lycoming O-540-E4C5 15 aircraft
Lycoming O-540-G1A5 6 aircraft
Lycoming TIGO-541-E1A 1 aircraft
Lycoming TIGO-541 series 37 aircraft
Lycoming TIO-360-C1A6D 3 aircraft
Lycoming TIO-360 series 15 aircraft
Lycoming TIO-540-A2B 4 aircraft
Lycoming TIO-540-A2C 6 aircraft
Lycoming TIO-540-C1A 9 aircraft
Lycoming TIO-540-J2BD 24 aircraft
Lycoming TIO-541-A1A 1 aircraft
Lycoming TIO-541-E1C4 9 aircraft
Lycoming TIO-541 series 273 aircraft
Lycoming VO-540-B1B3 3 aircraft
Lycoming VO-540-C2A 6 aircraft
Lycoming VO-540 series 110 aircraft

Dates and paperwork

In force since
January 13, 1977
Docket
Unknown
Status
Current
The FAA's document
Read the order on the FAA's site

The order itself the regulatory text, as published

Show the full text (7,262 characters)
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.

Source: FAA Dynamic Regulatory System, airworthiness directives. The FAA's document is the authority; the register counts are this site's, from the FAA register of October 5, 2026. Connections as data: /graph/directive/73-23-01.json · aircraft systems.