Service Bulletin No. 594

Reprint of Hartzell Engine Technologies LLC Mandatory Service Bulletin 040A


DATE: January 10, 2011


All Lycoming new, overhauled, or rebuilt turbocharged or turbo normalized engines, shown in Table 1, shipped before October 27, 2010 with HET or Kelly turbocharger installed and has less than 50 hours of service time (Refer to the attached Table 2 of HET Mandatory Service Bulletin 040 A) HET or Kelly turbocharger shipped as a spare part from Lycoming Engines before October 27, 2010 (Refer to the attached Table 1 and 1b of HET Mandatory Service Bulletin 040 A.)


Turbochargers with 0 to 10 hours of time in service, before further flight; for turbochargers with 10 to 50 hours of time in service, do this check within the next 10 hours of time in service.

Lycoming Service Bulletin No. 594 applies only to Lycoming engines with Hartzell Engine Technologies LLC (HET) or Kelly turbochargers with Lycoming part numbers identified in Table 1 below and Table 1b of the attached HET Service Bulletin 040 A. The part numbers are on the data tag of the turbocharger.

Get It Exchanged

Use our Engine Exchange Program to order a new, rebuilt, or overhauled engine to experience more airtime and less downtime.