Aircraft Alternator
Maintenance Manual
ES1031
24-30-01
Rev. B: 20 Apr. 2022
Page: 6-17
© 2022 - Hartzell Engine Technologies - All rights reserved
(3) If a strike has occurred, (especially if arc burns appear on the propeller) remove the alternator and
inspect for arc marks. If gear driven, observe the drive coupling teeth as an arc here may leave
raised metal which will also cause further damage when running. If belt driven, the most likely
damage will occur within the alternator or it’s attachments or mounting brackets. Observe the
mounting points and bracketry for arc marks at joints and attachments. Use the appropriate engine
and/or aircraft, manufacturers maintenance manuals or service instructions to accomplish this task.
(4) If evidence of a strike is observed and the alternator is being overhauled or replaced due to this
evidence or due to malfunction, it is advised that the entire aircraft/rotorcraft electrical system be
inspected. Use the appropriate engine and/or aircraft/rotorcraft manufacturers maintenance manuals
or service instructions to accomplish this task.
(5) If there is no indication of arcing or other damage and a lightning strike cannot be confirmed,
reinstall the alternator and check per the applicable airframe and engine manufacturers
maintenance or service instructions.
(6) Upon completion, test run the engine per the POH or AFM prior to returning the aircraft to service.
Make an appropriate logbook entry concerning the lightning strike.
6.17 Storage and Shelf Life
:
A. Storage
When storing a new, overhauled or repaired alternator, there are several categories to consider. Short term
storage or long term storage on or off the aircraft. Short term storage will be considered as storage up to but
not exceeding twenty-four (24) calendar months. Long term storage will be considered as storage up to but
not exceeding twelve (12) calendar years. There are different methods for each type of storage.
(1) Short term, if on the shelf, requires only that the unit be kept inside in the original packaging. If unit
is on the aircraft (or unmounted engine) no additional action other than that required for the engine or
aircraft is needed.
(2) Long term, if on the shelf, requires that the alternator be removed from the box and from the plastic
bag as originally packaged. Discard the bag. Wipe or lightly spray outside and all openings with
electrically friendly preservative oil. Wrap tightly with a waxed type paper (new bags may be used if
specifically formulated for the storage of metal products). Place back into original shipping container
and store in a cool dry environment.
(3) If it is anticipated or determined that the aircraft (or unmounted engine) will be in a long term storage
situation, as soon as practicable, lightly spray outside and all openings with electrically friendly
preservative oil. No additional action other than that required for the engine or aircraft is needed.
(4) At the expiration of twelve (12) calendar years from date of manufacture or overhaul, regardless of
storage or usage, the unit must be overhauled.
B. Shelf Life
(1) All alternators (HET, Kelly, ESI, Prestolite or others now manufactured by HET) have a shelf life of up to,
but not to exceed, twelve (12) calendar years at which time the unit must be overhauled.
Shelf life time
applies only if storage requirements are observed.
