AD/Dauphin/83 Amdt 1 Tail Rotor and Tail Gearbox Support Inspection (Cth)

AIRWORTHINESS DIRECTIVE

On the effective date specified below, and for the reasons set out in the background section, the CASA delegate whose signature appears below revokes Airworthiness Directive (AD) AD/DAUPHIN/83 and issues the following 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.

Eurocopter SA 360 and SA 365 (Dauphin) Series Helicopters

AD/DAUPHIN/83 Amdt 1 Tail Rotor and Tail Gearbox
Support - Inspection 12/2006

Applicability:

SA 365 N1, AS 365 N2 and AS 365 N3 helicopters.

Requirement:

1.    Check that the Tail Gear Box (TGB) oil level is at maximum, in accordance with paragraph 2.B.1. of EUROCOPTER AS 365 Alert Service Bulletin (ASB)
No. 05.00.54 or later DGAC approved revisions.

2.    Carry out a check of the TGB to ensure that there are no chips at the magnetic plug, in accordance with paragraph 2.B.2 of EUROCOPTER AS 365 ASB
No. 05.00.54 or later DGAC approved revisions.

a.     If there are no chips, resume flights.

b.    If there are chips, carry out the actions to be applied after chip detection at the magnetic plug, in accordance with paragraph 2.B.2.b of EUROCOPTER AS 365 ASB No. 05.00.54 or later DGAC approved revisions.

c.     If the quantity of chips is above the removal criteria, replace the TGB with a TGB in airworthy condition.

d.    If the quantity of chips is below the removal criteria, carry out a tactile check for absence of axial play in the Tail Rotor Hub (TRH) pitch change spider, in accordance with paragraph 2.B.2.b.2 of EUROCOPTER AS 365 ASB
No. 05.00.54 or later DGAC approved revisions as is applicable.

(i)    If there is no axial play in the TRH pitch change spider, resume flights.

(ii)   If axial play is found in the TRH pitch change spider, replace the bearing of the pitch control rod, in accordance with paragraph 2.B.2.b.2 of EUROCOPTER AS 365 ASB No. 05.00.54 or later DGAC approved revisions as is applicable.

Note:  EASA EAD 2006-0258-E R1 dated 24 August 2006 refers.  This AD supersedes EASA EAD 2006-0051-E.

Compliance:

1.    During the check after the last flight of the day (ALF-check) or during each flight-related check (15 hours or 7 days), according to the helicopter version.

2.    For TGBs not equipped with a magnetic plug with electrical indicating, at the latest at the next scheduled check of the magnetic plug following the effective date of this AD and then every 25 flying hours.

For TGBs equipped with a magnetic plug with electrical indicating, at the latest at the next scheduled check of the magnetic plug, or after illumination of the TGB “CHIP” warning light, following the effective date of this AD, and then every 100 flying hours and after each illumination of the TGB ‘CHIP” warning light.

This Amendment becomes effective on 23 November 2006.

Background:

This AD was in response to an event where tail rotor pitch control loss occurred during the landing phase of the helicopter.  Failure of the pitch control rod bearing can lead to loss of control of the tail rotor and subsequent loss of control of the helicopter.

This amendment introduces the following actions:

-    maintaining TGD oil level at the maximum level,

-   checking of axial play in the tail rotor pitch control rod bearing, in case of metallic particle(s) detected at the TGB magnetic plug.

The original issue of this AD became effective on 27 February 2006.

James Coyne
Delegate of the Civil Aviation Safety Authority

12 October 2006