TB 1--1520--237--20--236
(2) Ferry Status - Same as paragrah 1.a..
d.
Maintenance Trainers (Category A, and B). Same as paragraph 1.a..
e.
Component/Parts in Stock at All Levels (Depot Level and Others), including War Reserves. N/A.
f.
Components/Parts in Work (Depot Level and Others). N/A.
NLT 27 August 2001and report IAW para 14.a.(2) NLT 29 August 2001.
4.
Summary of Problem.
a. A main rotor expandable pin was found fractured during a routine spindle cuff inspection. The air-
craft had undergone a recent Preventive Maintenance Service (PMS-1). The fracture was discovered during
a spindle lug NDI inspection. This is the third reported occurence of a potentially catastrophic failure event.
Recent changes to applicable PMS-1 checklists were made to specifically address inspection of the blade
pin condition and security.
b.
Manpower/downtime and funding impacts see para 12.
c.
The purpose of this TB is to:
(1) Implement changes to all H-60 series maintenance manuals increasing built in tension of
main rotor expandable pins and expand Preventive Maintenance Service (PMS-1) scheduled blade pin in-
spection requirements.
(2) Conduct a fleetwide one-time inspection to determine and adjust as necessary, main rotor
blade pin tension per this TB and appropriate maintenance installation procedures..
End Items to be inspected . All H-60 series aircraft.
6.
Assembly Components to be Inspected. N/A
7.
Parts to be Inspected.
NOMENCLATURE
PART NUMBER
NSN
Pin, Expanding Grip
70103-08107-102
Pin, Expanding Grip
70103-08107-103
No NSN assigned
Inspection Procedures.
NOTE
Main rotor blades and blade pins do not have to be removed for this inspection. However, it is
critical that all tension be removed from the pin by lifting the blade to perform proper tension check.
a. Utilizing proper procedures, carefully raise the main rotor blade to remove all tension on the expand-
able blade pins.
b.
Release expandable pin handle from the lower nut and open handle.
c.
Check expandable pin tension as follows:
(1) Using spring scale, place end of spring scale in the handle nut hole and pull down in closing
direction.
(2) Keeping the spring force perpendicular to the long, riveted section of the handle, the force
to close the handle shall now be 25 pounds minumim.
(3) If force is 25 pounds or above, close and secure handle. Ensure that at least two threads
extend beyond the nut. The inspection is complete, proceed to paragraph 9.a.(3)..
2
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