Fuel Pump Leak Inspection and Diaphragm Replacement, Hartzell Engine Tech (HET) Alert Service Bulletin No.233
This Mandatory Service Bulletin (MSB) transmits HET Alert Service Bulletin No. 233 to ensure that
owners, operators, and maintenance providers of Lycoming engines are aware of the necessity to inspect and
replace affected Fuel Pump Diaphragms.
Parts affected by this Service Bulletin include HET P/N 063F-0001 diaphragms in inventory or installed in
Fuel Pumps with a cure date of 02/25 through 02/26. Affected Fuel Pumps contain Serial Numbers HCEN001FP
through H-DFN010FP. Table 1 in HET Alert Service Bulletin No. 233 lists affected HET Fuel
Pump P/N’s. Affected Lycoming P/N’s are listed below in Table 1.
Table 1
See attached PDF
