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68-08-08: Hydraulic Valve

FAA order 68-08-08 is an airworthiness directive in force since May 19, 1968. The FAA's subject line: Hydraulic Valve. It names the Lycoming IGSO-480-A1E6, Lycoming IVO-360-A1A, Lycoming TVO-435-A1A, Lycoming TVO-435-B1A, Lycoming TVO-435-D1A, Lycoming TVO-435-F1A, Lycoming TVO-435-G1A, Lycoming TVO-435-GIA, Lycoming VO-435-A1D, Lycoming VO-435-A1F, Lycoming VO-435-B1A, Lycoming VO-435 series, Lycoming VO-540-B1B3, Lycoming VO-540-C2A, Lycoming VO-540 series engines: about 431 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
Models: IGSO-480-A1A6, IGSO-480-A1B6, IGSO-480-A1C6, IGSO-480-A1F6, IVO-360-A1A, 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, VO-360-A1A, VO-360-A1B, VO-360-B1A, VO-435-A1A, VO-435-A1B, VO-435-A1C, VO-435-A1D, VO-435-A1E, VO-435-A1F, VO-435-B1A, VO-540-A1A, VO-540-A2A, VO-540-B1A, VO-540-B1B, VO-540-B1B3, VO-540-B1C, VO-540-B1D, VO-540-B1E, VO-540-B1F, VO-540-B1H3, VO-540-B2A, VO-540-B2C, VO-540-B2D, VO-540-B2E, VO-540-B2G, VO-540-C1A, VO-540-C1B, VO-540-C1C3, VO-540-C2A, VO-540-C2B, VO-540-C2C
Engine series: Lycoming IGSO-480-A1E6 1 aircraft
Lycoming IVO-360-A1A 2 aircraft
Lycoming TVO-435-A1A 1 aircraft
Lycoming TVO-435-B1A 2 aircraft
Lycoming TVO-435-D1A 2 aircraft
Lycoming TVO-435-F1A 1 aircraft
Lycoming TVO-435-G1A 1 aircraft
Lycoming TVO-435-GIA 88 aircraft
Lycoming VO-435-A1D 3 aircraft
Lycoming VO-435-A1F 15 aircraft
Lycoming VO-435-B1A 6 aircraft
Lycoming VO-435 series 190 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: May 19, 1968
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 (1,175 characters)

68-08-08	LYCOMING:  Amendment 39-584.  Applies to VO, IVO-360 Series: VO, TVO-435 Series; IGSO-480 Series excluding models IGSO-480-A1D6, -A1E6, -A1G6; VO, IVO, TIVO-540 Series engines which incorporate the P/N 76289 hydraulic valve lifter. 
	Compliance required as indicated. 
	To prevent further valve failures replace hydraulic lifter P/N 76289 with P/N 78289 at the time in service specified below: 
	(a)	TVO-435, VO-540, IVO-540, and TIVO-540 Series engines shall comply within 50 hours' time in service after the effective date of this AD. 
	(b)	VO-360, VO-435, and IGSO-480 Series engines with less than 600 hours' time in service on P/N 76289 as of the effective date of this AD, shall comply prior to the accumulation of 650 hours' time in service on P/N 76289. 
	(c)	VO-360, IVO-360, VO-345, and IGSO-480 Series engines with 600 or more hours' time in service on P/N 76289 as of the effective date of this AD shall comply within the next 50 hours' time in service. 
	(NOTE: Lycoming Service Bulletin No. 314A provides serial numbers of new and factory remanufactured engines which have the P/N 76289 hydraulic valve lifter.) 
	This amendment effective May 19, 1968.

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/68-08-08.json · aircraft systems.