AD/At/24 Amdt 2 Overturn Skid Plate (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/AT/24 Amdt 1 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.

Airtractor AT-300, 400 and 500 Series Aeroplanes

AD/AT/24 Amdt 2 Overturn Skid Plate 3/2009

Applicability:

Group 1 aircraft Models AT-300, AT-301, AT-302, AT-400, AT-400A, AT-401,
AT-401A, AT-402, AT-402A, and AT-402B, with serial numbers -0001 through
-1196, and; Models AT-501, AT-502, AT-502A, and AT-502B with Serial Numbers
-0001 through -2620.

Group 2 aircraft Model AT-401B, with serial numbers -0952 through -1196.

Requirement:

For Group 1 aircraft:

If overturn skid plate kit part number (P/N) 11411-1-500 or an FAA-approved equivalent part number is already installed, then install P/N 11411-1-501 modification kit; in accordance with Snow Engineering Co. Service Letter (SL) No. 97, revised 7 November 2007, or SL No. 97, revised 19 September 2008.

If there is no overturn skid plate installed, then install overturn skid plate modification kit P/N 11411-1-502 or an FAA-approved equivalent part number; in accordance with SL No. 97, revised 7 November 2007, or SL No. 97, revised 19 September 2008.

For Group 2 aircraft:

Install P/N 11411-1-501 modification kit in accordance with SL No. 97, revised 19 September 2008.

Note:  FAA AD 2008-26-01 Amdt 39-15767 refers.

Compliance:

For Group 1 aircraft:

Within 180 days after 31 July 2008.

For Group 2 aircraft:

Within 180 days after 12 March 2009, unless already accomplished.

The compliance time for Requirement 1 remains unchanged by this issue of the Directive.

This Amendment becomes effective on 12 March 2009.

Background:

The FAA received accident reports on Model AT-301 and AT-401 aircraft which indicate that the aircraft skids tail first during an overturn.  As a result, the windshield and curved overturn tube act as a scoop, foreign material enters the cockpit if the canopy is damaged; and this foreign material then enters into the cabin area and possibly contributes to pilot deaths.  The actions required by this Directive are intended to minimise the possibility of dirt or mud penetrating the cockpit during an overturn skid and causing pilot asphyxia or injury.

Since the original issue of this Airworthiness Directive, there have been reports of the bolts that attach the forward end of the original design overturn skid plate breaking in an overturn accident.  This allowed the skid plate to rotate around the rear attach point and the forward end of the plate to enter the cockpit area.

Amendment 1 was issued in order to prevent the front and rear connections of the overturn skid plate to the airframe from breaking.

Amendment 2 is issued in response to a new FAA AD, which retains the current actions required by this Directive but adds the requirement to modify the overturn skid plate installed Model AT-401B aircraft.

David Punshon
Delegate of the Civil Aviation Safety Authority

7 January 2009