AD/R44/22 Main Rotor Blade Leading Edge and Tip Cap Area Skin (Cth)

AIRWORTHINESS DIRECTIVE

For the reasons set out in the background section, the CASA delegate whose signature appears below issues the following Airworthiness Directive (AD) under subregulation 39.001(1) of CASR 1998.  The AD requires that the action set out in the requirement section (being action that the delegate considers necessary to correct the unsafe condition) be taken in relation to the aircraft or aeronautical product mentioned in the applicability section: (a) in the circumstances mentioned in the requirement section; and (b) in accordance with the instructions set out in the requirement section; and (c) at the time mentioned in the compliance section.

Robinson R44 Series Helicopters

AD/R44/22 Main Rotor Blade Leading Edge
and Tip Cap Area Skin 3/2008 DM

Applicability:

Model R44 helicopters, serial numbers 0001 through 1670, and R44 II helicopters, serial numbers 10001 through 11570.

Requirement:

1.    a.     Using a 10x or higher magnification, visually inspect for skin separation along the leading edge of any exposed (bare metal) blade skin aft of the skin-to-spar bond line on the lower surface of each main rotor blade.  If there is any skin separation, before further flight, replace the blade with a serviceable blade.

b.    Perform a “tap test” to detect any separation or void on the skin-to-spar bonded areas on the lower blade skin aft of the skin-to-spar bond line of each main rotor blade using a suitably weighted coin.  If there is any separation or any void, before further flight, replace the blade with a serviceable blade.

c.     Remove both main rotor blade tip covers.  Using a 10x or higher magnification, visually inspect the blade tip area exposed when the blade tip covers were removed.  “Tap test” the skin-to-cap bond joints on both upper and lower surfaces.  If corrosion, separation, or any void is detected, before further flight replace the blade with a serviceable blade.

d.    Repaint any exposed area of the main rotor blade according to the Compliance Procedure, paragraphs 3 through 7, of Robinson R44 Service Letter SL-32 Revision A, dated 29 March 2007.

2.    Thereafter, if the main rotor blade has been found serviceable by the Requirement 1 inspections, visually check for any exposed (bare metal) skin-to-spar bonded area on the lower surface of each blade within the outboard
24-inches, paying particular attention to the last 10-inches before the tip.

If a pilot finds any area of skin bare metal in the outboard 24-inches of either blade, before further flight, an appropriately qualified person must accomplish Requirement 1 of this Directive.

Note: FAA AD 2007-26-12 Amdt 39-15314 refers.

Compliance:

1.    Within 10 hours time in service after 18 January 2008, unless already accomplished.

2.    Before each flight.

This Directive shall be entered on the maintenance release as maintenance required.  The Requirement 2 visual inspection may be performed and certified by the Pilot in Command who has been trained to do the inspection by an appropriately qualified person.  In this case, a copy of this Directive is to be carried in the aircraft.

This Airworthiness Directive becomes effective on 18 January 2008.

Background:

The FAA received eleven reports of main rotor blade debond, some occurring in flight causing the pilot to experience excessive vibrations and land as a consequence, and some found during routine maintenance.  The actions specified in this Directive are intended to detect blade skin debond and to prevent blade failure and subsequent loss of control of the helicopter.

David Punshon
Delegate of the Civil Aviation Safety Authority

7 January 2008