AD/HU 369/94 Amdt 2 - Main Rotor Blade Doublers (Cth)

McDonnell Douglas (Hughes) and Kawasaki 369 Series Helicopters

AD/HU 369/94 Amdt 2

Main Rotor Blade Doublers 11/98

Applicability: Model 369A, 369D, 369E, 369F, 369FF, 369H, 369HE, 369HM, 369HS, 500N, 600N, and OH-6A helicopters with the following main rotor blades installed: part number (P/N) 369A1100-507, with serial number (S/N) D139 through D203, D209 through D223; P/N 369D21100-517 with S/N H664, H665, H667, H669, H671, H672, H674, H676, H679, H680, H683 through H724, H726 through H999, J000 through J039, J041 through J055; or P/N 369D21102-517 with S/N 1976 through 2100, 2106 through 2115.

Requirement: 1. For applicable Model 369, 500N, and OH-6 helicopters:

1. With each blade lifted off the droop stop, using a 10x or higher magnifying glass, visually inspect the blade for any chordwise cracking emanating from the root fitting edge on the blade lower surface doubler and skin or cracks on the doubler adjacent to the root end fitting (Figure 1), as specified in the Accomplishment Instructions in Boeing McDonnell Douglas Helicopter Systems Service Bulletin (SB) SB369H-243R3, SB369E-088R3, SB500N- 015R3, SB369D-195R3, SB369F-075R3, or SB 600N-007R2, as applicable. If any cracking is discovered, remove the blade and replace it with a serviceable blade.

b. With each blade lifted off the droop stop, inspect the lower surface for missing or cracked adhesive or paint at the root end fitting-to-doubler bond line (Figure 1 of the SB Accomplishment Instructions). If any missing or cracked adhesive or paint is discovered, remove and inspect the blade in accordance with paragraph 3.E. of Part II of the Accomplishment Instructions in McDonnell Douglas Helicopter Systems Service Information Notice HN-239, DN-188, EN- 81, FN-67, or NN-008, as applicable. If there is any disbonding in excess of the allowable margins specified in paragraph 3E of Part II of the applicable service information notice, remove the blade and replace it with a serviceable blade.