AD/R44/10 Amdt 1 - Main Rotor Blade (Cth)

Robinson R44 Series Helicopters

AD/R44/10 Amdt 1

Main Rotor Blade 14/98 DM

Applicability: Model R44 helicopters, serial numbers 0002 through 0486, with main rotor blades part number (P/N) C016-1 installed.

Requirement: 1. Inspect the main rotor blade skin around both inboard trim tab alignment rivets as follows, referring to Figure 1 of this Directive:

(a) Remove all paint around both rivets, exposing an area of approximately ¾ inch in diameter, at the inboard trim tab on the top and bottom of each blade (four places per blade). Use 180 grit or finer abrasive paper, followed by 600 grit or finer paper to eliminate course sanding marks. Sand only in a spanwise direction. Do not use chemical paint strippers.

(b) Inspect the blade skin around the rivets on the blade upper and lower surfaces (four locations) using a dye penetrant method.

Note 1: Chordwise cracks in the paint up to 2 inches long which are located along either inboard or outboard edge of the trim tab are acceptable.

(c) Clean the sanded areas prepared with 111-trichloroethane or methyl ethyl ketone and then apply clear lacquer to seal the unpainted areas.

Note 2: Do not bend the inboard main rotor blade tabs from their present position or utilise them for any subsequent blade tracking adjustment.

2. Thereafter, using a 5-power or higher magnifying glass, visually inspect the upper and lower blade skin surfaces around the inboard trim tab rivets (four locations) for cracks.

3. Replace main rotor blades P/N C016-1 with main rotor blades P/N C016-2.

Note 3: Robinson Service Bulletin SB-28, dated 18 June 1998, refers.

Note 4: Installation of a set of main rotor blades, P/N C016-2, constitutes terminating action for the requirements of this Directive.