TB 1-1520-240-20-150
(1) Lock out the Rotor Heads: H--47D/F per TM 55--1520--240--23; Task 11--28, Install Servocy-
linder Safety Blocks and Task 5--97, Remove Pitch Link (Pitch Link Lockpins installed). MH--47E per TM
1--1520--252--23; Task 11--33, Install Servocylinder Safety Blocks and Task 5--145, Remove Pitch Link (Pitch
Link Lockpins Installed).
NOTE
Prior to removing hardware, thoroughly wipe clean all upper seal
surfaces (only), by hand with a lint free cloth. Remove only the Upper
Seal, P/N 114R3428--1. Do not remove the Upper Bearing Retainer, P/N
114R3126--4. Only 12 bolts and washers (Aft) or nuts and washers (Fwd)
need to be removed.
(2) Remove Forward and Aft Swashplate Upper Seal, P/N 114R3428--1, per TM
55--1520--240--23, Task 5--122, paragraphs 1a and 2a (H--47D/F) or TM 1--1520--252--23, Task 5--175, para-
WARNING
If this inspection is performed on aircraft, ensure no FOD enters
the bearing. Do not attempt to clean or wipe the bearing prior to
performing the next step.
(3) Use a flashlight or other suitable light source to visually inspect for raised, overlapping or bro-
ken cage segments. Inspect for orange/red pieces of debris. The lower grease seal is elastomeric orange/red
in color: therefore this type of rubber debris may be indicative of damage to this lower seal.
WARNING
Do not use cloths or rags to clean the bearing area, as this may
snag or catch on the bearing cage and disturb the balls.
(4) Wipe away excess grease in cavity using fingers. Use a flashlight or other suitable light source
to visually inspect for raised, overlapping or broken cage segments or multiple adjacent uncaged ball bearing.
Inspect for orange/red pieces of rubber debris.
NOTE
The design of the bearing allows for up to 3 individual cage segments
with each segment separated by one uncaged ball.
(5) If any of these conditions are found, except for those in the note above, the Swashplate As-
sembly shall be considered unserviceable and disposition is in accordance with paragraph 11d of this mes-
sage. This inspection will now be required every 100 flight hours for all H--47 aircraft.
NOTE
If replacement self--locking nuts are not available, re--use of the original
nuts is authorized provided they meet the following torque requirement.
The torque required to start the nut rotating with a minimum of one full
thread extending from the end of the nut shall be at least 7 inch--pounds.
The standard procedure of using new nuts at each removal and
reinstallation shall be followed as soon as new nuts are available.
(6) If the bearing passes the inspections of 3 and 4, install the Swashplate Upper Seal, P/N
114R3428--1, per TM 55--1520--240--23, Task 5--125, Paragraphs 7b and 8e--h (H--47D/F) or TM
1--1520--252--23, Task 5--179, Paragraphs 7b and 8e--h (MH--47E). If nuts were reused on forward swash-
plate, apply a torque stripe to all nuts for visual inspection reference. A Daily Inspection will be required until
new nuts are installed.
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