AD/ATR 42/26 Amdt 1 Windows Cockpit Forward Side Windows (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/ATR 42/26 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.

Avions de Transport Regional ATR 42 Series Aeroplanes

AD/ATR 42/26 Amdt 1 Windows - Cockpit Forward Side Windows 17/2011

Applicability:

Model ATR 42-200, 42-300, 42-320, 42-400 and 42-500 aeroplanes that are equipped with PPG Aerospace cockpit forward side glass windows part number (p/n) NP158862-1 and/or p/n NP158862-2.

Requirement:

As per EASA Emergency Airworthiness Directive 2009-0159-E, dated 20 July 2009.

Compliance:

As per EASA Emergency Airworthiness Directive 2009-0159-E, dated 20 July 2009.

This Amendment becomes effective on 19 August 2011.

Background:

The investigation revealed some anomalies on the forward side window at the level of the z-bar on the windows external side and at the level of the inner retainer on the windows internal side.  These anomalies are considered as precursors of this failure.

Air or water leakages between the z-bar and the outer glass ply, or between the inner retainer and inner glass ply indicates the presence of deteriorating structural components in the window.

It must also be noted that neither ATR nor PPG Aerospace authorizes repairs on the window Z-bar / Z-bar sealant.

Any attempted repairs on these forward side window Z-bars/Z-bar sealants could lead to a similar event that has originated this AD.

An in-flight loss of a forward side window could have catastrophic consequences for the aeroplane and/or cause injuries to people on the ground.  The loss of the forward side window while the aeroplane is on the ground with a positive differential cabin pressure could also cause injuries to people inside or around the aeroplane.

This amendment is issued to remove ATR 72 aircraft from the applicability.

The original issue of this Airworthiness Directive became effective on 22 July 2009.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

12 August 2011