Summary of the Problem. - TB-1-1520-237-20-2140002

TB 1152023720214

e. Maintenance Trainers (Category A, and B). Same as paragraph 1.a.

Component/Parts in Stock at All Levels (Depot and Others) Including War Reserves .

(1) Wholesale Stock. Report receipt of this message IAW paragraph 14c(1).

(2) Retail Stock. Report receipt of this TB IAW paragraph 14c(2). Upon receipt of this TB, com-

manders and others maintaining retail stock at installation level and below shall contact the support aviation

unit to perform the inspection required by paragraph 8 and the correction procedures of paragraph 9 on dis-

crepant materiel. Disposition of discrepant materiel will be IAW paragraph 10d. Report compliance with this

message IAW paragraph 14d(2).

g. Component/Parts In Work (Depot Levels and Others). N/A.

Task/Inspection Suspense Date. Within next 10 flight hours/14 days.

Reporting Compliance Suspense Date. No later than 19 August 1999 IAW 14.a of this TB.

Summary of the Problem.

a. During routine maintenance, a main rotor blade expandable pin, P/N 7010308107102, was found

to have an expandable "outer" segment without the slot that allows expansion and contact with the hole when

the handle is rotated. Structural analysis revealed that the lack of a slot in one or more of the segments could

impact the service life of the blade cuff and spindle. The amount of service life degradation is dependent upon

the location of the discrepant segment of the pin, the location of the pin (i.e. lead or lag), the number of hours

the discrepant pin has been installed, and the manufacturers specific pin configuration. A review of the

manufacturing process revealed that all pins manufactured for the H60 aircraft are suspect. A onetime

inspection of all pins is necessary to locate any additional discrepant pins. For each nonconforming pin

found, an engineering analysis is necessary to determine the impact on the fatigue life of the mating spindle

and main rotor blade cuff. This impact can range, depending upon the previously mentioned factors, from

no impact to a reduced life for the specific parts.

b. For manpower/downtime and funding impacts, see paragraph 12.

c. The purpose of this message is to implement a onetime inspection of H60 main rotor expandable

pin, P/N 7010308107101/102/103, for conformation and to implement a process to apply reduced service

life on specific main rotor blade, blade cuff and spindle where appropriate and to remove P/N

7010308107101 expandable pins from service.

End Items to be inspected. All H60 aircraft.

Assembly components to be Inspected. N/A.

Parts to be Inspected.

NOMENCLATURE

PART NUMBER

NATIONAL STOCK NUMBER

Pin, Expandable Grip

7010308107101

5315010969173

Pin, Expandable Grip

7010308107102

5315013290707

Pin, Expandable Grip

7010308107103

NO NSN

Inspection Procedures.

a. Remove main rotor blade expandable pins IAW TM 1152023723 or TM 1152025023 from

each rotor blade, one at a time.

b. Visually inspect each P/N 7010308107101/102/103 expandable pin for nonconforming outer

segments. Between each "outer" segment is and "inner" segment that does not have a slot and appears to

be a solid washer. When the handle is closed the inverted cone shaped outer (slotted) segments ride up on

the cone shaped inner (unslotted) segments causing the outer segments to expand. Expandable pins have

a slot in every outer segment. Any missing, broken, solid, or partially slotted outer segments are cause for