INSPECTION AND CHECK
61-00-39
Page 5-31
Rev. 17 Apr/20
Propeller Owner’s Manual
139
C. Foreign Object Strike/Ground Strike
(1) General
(a) A foreign object strike can include a broad spectrum
of damage, from a minor stone nick to severe ground
impact damage.
1 A conservative approach in evaluating the
damage is required because there may be hidden
damage that is not readily apparent during an
on-wing, visual inspection.
(b) A foreign object/ground
strike is defined as:
1 Any incident, whether or not the engine is
operating, that requires repair to the propeller
other than minor dressing of the blades.
a Examples of foreign object/ground strike
include situations where an aircraft is
stationary and the landing gear collapses
causing one or more blades to be significantly
damaged, or where a hangar door (or other
object) strikes the propeller blade(s).
b These cases should be handled as foreign
object/ground strikes because of potentially
severe side loading on the propeller hub,
blades, and retention bearings.
2 Any incident during engine operation in which
the propeller impacts a solid object that causes
a drop in revolutions per minute (RPM) and
also requires structural repair of the propeller
(incidents requiring only paint touch-up are not
included). This is not restricted to propeller strikes
against the ground.
3 A sudden RPM drop while impacting water, tall
grass, or similar yielding medium, where propeller
blade damage is not normally incurred.
(c) In the event of a foreign object/ground strike, an
inspection is required before further flight.