Aircraft Alternator
Maintenance Manual
ES1031
24-30-01
Rev. B: 20 Apr. 2022
Page: 4-1
© 2022 - Hartzell Engine Technologies - All rights reserved
CHAPTER 4 - CHECK
4.1 General
A.
This section defines the various checks and inspections needed to assure reliable and safe operation of the
alternator while in service. They are listed in hours time in service (TIS) or in calendar time, whichever is applicable
and are the first to occur when offered a choice. Some maintenance is one time initial and others are recurring.
B. HET recommended maintenance and checks including TIS may be superseded by the aircraft or engine
manufacturer’s established time limits and schedules based on experience and/or unique requirements
under engine or airframe Type Certificate.
4.2 Inspection Checks
100 Hours TIS & each 100 hours thereafter. (or each annual/event, the first to occur)
Perform a check of the alternator assembly. Note through bolt security and proper safety wire application.
Re-torque if bolts are found loose. Check the alternator to engine mounting bolts for proper torque per
aircraft, rotorcraft and/or engine service instructions or maintenance manual. Inspect area around the brush
holder for soot. If a large amount of soot appears, remove each brush and check for wear or damaged
brushes. If severe wear has occurred, check slip rings for gouges or scratches. Check all terminal hardware
for tightness and insulators for condition.
500 Hours TIS & each 500 hours thereafter. (or each two years, the first to occur)
Remove each brush and check for wear or damaged brushes. If brush shows more than 50% wear or has
chips or damage, replace brushes (brushes must be replaced as a set only). New brushes are 0.50 inch
(12.7 mm) long. With the alternator removed, check the drive coupling or visually check belt and belt drive
line components. Adjust belt tension to proper values per engine/aircraft service instructions or maintenance
manual. Examine the alternator insulators and replace if cracked or burnt. Inspect the aluminum housing
for surface corrosion, clean and treat. Inspect housings for cracks around through bolt holes and ears.
TBO Unlimited Hours TIS
Overhaul or replacement is based on the condition of the alternator.
Overhaul time may vary based on
cooling, electrical load and general service. When published, the aircraft OEM TBO shall supersede this
HET recommendation.
