ENSTROM F-28F/280F SERIES MAINTENANCE MANUAL
Rev.
5
MM-4-61
Nov
5/13
B. Blade damage exceeds limits of paragraph 9-9, but has not contacted the airframe or
other rigid object and shows no visible kinks, ripples in the skin or trailing edge. Perform the
following:
(1) Replace the blade(s).
(2) Refer to the latest revision of Textron-Lycoming Service Bulletin 533 for the
recommended engine inspection.
(3) Check the main rotor shaft run out. Maximum allowed is .012 inches/.305 mm FIM.
(4) Inspect the tail rotor driveshaft taper pins (para. 10-6, H) and flex packs (para. 10-6,
C).
NOTE
If the main rotor shaft run out, taper pins, or flex packs do not meet inspection
requirements, proceed to paragraph 4-59.
4-58. Main Rotor Blade Strike/Sudden Stoppage (Major) – Special Instruction
A. Obvious blade damage exceeding the limits of paragraph 9-9. Perform the following:
(1) Replace the damaged blade(s) and inspect the remaining blade(s).
(2) Remove the main rotor transmission including the upper pulley and tail rotor drive
shaft hub and return to Enstrom Helicopter Corporation for inspection and
overhaul/replacement.
(3) Remove the main rotor hub and inspect by liquid penetrant inspection and in
accordance with the inspection tables in para. 9-1, D, or return to Enstrom
Helicopter Corporation for inspection and overhaul/replacement.
(4) Inspect all flight control push-pull rods and torque tubes for sheared/damaged rivets
at the fittings, damaged rod ends, or sheared/damaged roll pins.
(5) Inspect all flight control bellcranks for buckling and elongated bolt holes.
(6) Inspect the lower swashplate for warped or cracked casting and for bent or
damaged guidetubes in the upper swashplate. Inspect the tie rod and universal rod
for straightness. Inspect the bolt holes for elongation.
(7) Replace all tail rotor driveshaft taper pins.
(8) Inspect the tail rotor driveshafts for complete or partial failure at the taper pin holes.
(9) Magnetic particle inspect the tail rotor driveshafts.
(10) Inspect the pylon structure at the gearbox mounting areas for broken or bent tubes.
Check the trueness of the four gearbox attachment points.
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