Applicability: Model R44 helicopters, serial numbers (S/N) 0002 thru 0486, with main rotor blades, part number (P/N) C016-1, installed, certificated in any category

Effective date: Upon receipt

Compliance : Required as indicated in FAA PL AD 98-12-19

Priority Letter issued on June 2, 1998. Docket No. 98-SW-25-AD.

Applicability: Model R44 helicopters, serial numbers (S/N) 0002 thru 0486, with main rotor blades, part number (P/N) C016-1, installed, certificated in any category.

NOTE 1: This AD applies to each helicopter identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For helicopters that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must use the authority provided in paragraph (f) to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any helicopter from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To detect main rotor blade skin fatigue cracks which originate from the inboard trim tab alignment rivet holes, that could result in failure of the main rotor blade and subsequent loss of control of the helicopter, accomplish the following:

(a) Within the next five hours time-in-service (TIS), perform a dye penetrant inspection of the blade skin around both inboard trim tab alignment rivets as follows, referring to Figure 1.

(1) Remove all paint around both rivets, exposing an area of approximately 3/4” in diameter, at the inboard trim tab on top and bottom of each blade (4 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.

(2) Inspect the blade skin around the rivets on the upper and lower surfaces (4 locations) using a dye penetrant method.

NOTE 2: 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.

(b) Clean the sanded areas prepared in accordance with paragraph (a) of this AD with 111-Trichloroethane or methyl ethyl ketone (MEK) and then apply clear lacquer to seal the unpainted areas.

NOTE 3: Do not bend the inboard main rotor blade tabs from their present position or utilize them for any subsequent blade tracking adjustment.

(c) Thereafter, prior to the first flight of each day, or at intervals not to exceed 5 hours TIS, whichever occurs first, using a 5-power or higher magnifying glass, visually inspect the upper and lower blade skin surfaces around the inboard trim tab rivets (4 locations) for cracks.

(d) If a crack is found, replace the main rotor blade with an airworthy main rotor blade before further flight.

(e) Installation of a set of main rotor blades, P/N C016-2, constitutes terminating action for the requirements of this AD.

(f) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Los Angeles Aircraft Certification Office, FAA. Operators shall submit their requests through an FAA Principal Maintenance Inspector, who may concur or comment and then send it to the Manager, Los Angeles Aircraft Certification Office.

NOTE 4: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Los Angeles Aircraft Certification Office.

(g) Special flight permits will not be issued.

NOTE 5: Robinson Helicopter Company R44 Service Bulletin SB-27A, revised May 29, 1998, pertains to the subject of this AD.

(h) Priority Letter AD 98-12-19, issued June 2, 1998, becomes effective upon receipt.

FOR FURTHER INFORMATION CONTACT: Mr. Fred Guerin, Aerospace Engineer, FAA, Los Angeles Aircraft Certification Office, Airframe Branch, 3960 Paramount Blvd., Lakewood, California 90712, telephone (562) 627-5232, fax (562) 627-5210.

FOR A COPY OF FIGURE 1, CALL AFS-610 AT (405) 954-4103 or CAA CZ AT (420) (2) 2011 2521.