AD/At 600/8 Overturn Skid Plate (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.

Airtractor 600 Series Aeroplanes

AD/AT 600/8 Overturn Skid Plate 8/2008

Applicability:

Air Tractor AT-602 with Serial Numbers -0337 through -1153.

Requirement:

If overturn skid plate kit part number (P/N) 11411-1-500 or an FAA-approved equivalent P/N is already installed, then install P/N 11411-1-501 modification kit.

If there is no overturn skid plate installed, then install overturn skid plate kit
P/N 11411-1-502 or an FAA approved equivalent part number.

Note:  FAA AD 2008-11-17 and Snow Engineering Service Letter #97, revised
7 November 2007 refers.

Compliance:

Within 180 days after the effective date of this AD.

This Airworthiness Directive becomes effective on 31 July 2008.

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 manufacturer installed an overturn skid plate which was intended to minimise the possibility of dirt or mud penetrating the cockpit during an overturn skid and causing pilot asphyxia or injury.

There have subsequently 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.  This Airworthiness Directive is issued to ensure overturn skid plates are installed and, if already installed, prevent the front and rear connections of the overturn skid plate to the airframe breaking.

David Villiers
Delegate of the Civil Aviation Safety Authority

13 June 2008