AD/AS 355/94

Load Compensator Levers

7/2007 TX

Applicability:

AS 355 N and AS 355 F2 helicopters.

Requirement:

1.    Verify the part number (P/N) of the load compensator lever installed on the rotorcraft together with the P/N of the hydraulic actuator assembly as detailed in the accomplishment instructions of EUROCOPTER AS 355 Alert Service Bulletin (ASB) No. 67.00.29 revision 1, dated 27 April 2007 or later NAA approved revision.

Note 1:  Instead of inspecting the rotorcraft, a review of the helicopter maintenance records along with any other applicable data (rotorcraft logbook, Components list, etc...) is acceptable if each P/N can be positively determined from that review.

2.    When a P/N cannot be identified, do all actions as detailed in paragraph 2.B.2.of the accomplishment instructions of AS 355 ASB No. 67.00.29 revision 1 or later NAA approved revision to determine the relevant part numbers.

3.    For helicopters Pre-MOD 072065 (i.e. with hydraulic actuator assembly
355A75-1370-01 or 355A75-1370-03) on which a compensator lever P/N 355A27-0082-00 is found.

a.     Provided the rotorcraft has not been operated with the lever P/N
355A27-0082-00 installed, replace the lever with a lever P/N
355A27-0072-00 as instructed in paragraph 2.B.3.a. of the accomplishment instructions of ASB No. 67.00.29 revision 1 or later NAA revision.

b.    If the rotorcraft has been operated with the lever P/N 355A27-0082-00 installed, do all actions as instructed in paragraph 2.B.3.b. of the accomplishment instructions of ASB No. 67.00.29 revision 1 or later NAA revision.

4.    For helicopters Post-MOD 072065 (i.e. with hydraulic actuator assembly 355A75-1370-02 or 355A75-1370-04) on which a compensator lever P/N 355A27-0072-00 is found.

a.     Provided the rotorcraft has not been operated with the lever P/N
355A27-0072-00 installed, replace the lever with a lever P/N
355A27-0082-00 as instructed in paragraph 2.B.3.a. of the accomplishment instructions of ASB No. 67.00.29 revision 1 or later NAA revision.

b.    If the rotorcraft has been operated with the lever P/N 355A27-0072-00 installed, do all actions as instructed in paragraph 2.B.3.b. of the accomplishment instructions of ASB No. 67.00.29 revision 1 or later NAA revision.

5.    Do not install:

-      Load compensator lever P/N 355A27-0082-00 on any AS 355 N and F2 helicopters Pre-MOD 072065.(i.e. with hydraulic actuator assembly
355A75-1370-01 or 355A75-1370-03 installed); or

-      Load compensator lever P/N 355A27-0072-00 on any AS 355 N and F2 helicopters Post-MOD 072065 (i.e. with hydraulic actuator assembly 355A75-1370-02 or 355A75-1370-04 installed).

Note 2:  EASA AD 2007-0131-E dated 11 May 2007 refers.

Compliance:

1.    Before further flight, after the effective date of this AD.

2.    Before further flight, after the effective date of this AD.

3.    a.     Before further flight, after the effective date of this AD.

b.    Within 10 flight hours after the effective date of this AD.

4.    a.     Before further flight, after the effective date of this AD.

b.    Within 10 flight hours after the effective date of this AD.

5.    From the effective date of this AD.

This Airworthiness Directive becomes effective on 18 May 2007.

Background:

This emergency AD is issued following a report of yaw control restricted travel in operation following the replacement of the load compensator.  If not corrected, this condition could lead to the loss of control of the helicopter.  Investigation revealed that the load compensator lever was incorrectly referenced in the Illustrated Parts Catalogue (IPC).  Levers on helicopters Post-MOD 072065 (replacement of the load compensator hydraulic actuator) should be Part Number (P/N) 355A27-0082-00 and levers on helicopters Pre-MOD 072065 should be P/N 355A27-0072-00.  This AD mandates inspection to identify the load compensator lever and the hydraulic actuator assembly installed on helicopters, to verify their compatibility and replacement of improper P/Ns when an incompatibility is found.