Modification.

TB 1-1520-238-20-91

If no cracks are found proceed to paragraph 9, modification. Visually inspect the aft end of the

Longerons during each Phased Maintenance Inspection.

9. Modification.

Locate and drill a

diameter drain hole at the aft end of each

per fig. 1. Deburr.

Treat with MIL-C-81706 Corrosion Resistant Coating per Ref. 13.d. and rinse with distilled water.

Allow to dry.

Coat with MIL-P-23377 primer per Ref.

10. Repair Procedures.

Safe the helicopter IAW task 1.57 of reference 14.a.

Remove the Engine Nacelle IAW task 2.133 (LH) or 2.134 (RH) of ref. 14.a.

Remove all fasteners attaching the

to the Engine Nacelle. Also remove the four

fasteners shown in fig. 2. Note the location of all removed fasteners for later reinstallation,

Carefully pull back the Nacelle Skins until it clears the pin in the

and remove the

Longeron.

NOTE

Pin rivets (HI-Loks) may be reused if replacements are not available. If reused, install wet with

MIL-P-23377 primer. The collars cannot be reused.

Rework the

by trimming 0.17 inch from the aft end of the Fitting (Ref. figure 3). Clean

up the inside radii as required. Route out any remaining crack that extends into the center web.

Remove paint from the aft 1 .OO inch of the

using MIL-R-81294 Paint Remover per ref.

14.d.

Fluorescent Penetrant Inspect (Type I, Method C, Level 2) the aft 1 .OO inch of the Fitting per ref.

No cracks allowed.

Measure and note distance "A" on

to be repaired (Ref. figure 3).

Fabricate two Fittings from 1 .OO inch thick 303 CRES, hard, per QQ-S-766, to the dimensions

shown in figure 4 and using distance "A" measured in step 10.g. above, to fit in the

(Ref.

Figures 4 5). A maximum gap

between the Fittings and the

may be

shimmed. A shim is not required if the Longeron/Fitting gap is less than 0.002 inch.

Fabricate shims, if required. Use shim per MIL-S-22499 composition 1, Class 1 or 2, Type I, II, or

III.

Passivate the fabricated Fittings per QQ-P-35 by applying Pasa-Jell

(1) Clean fittings by solvent wiping with an oil free solvent.