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

Avions de Transport Regional ATR 42 Series Aeroplanes

AD/ATR 42/26 Windows - Cockpit Forward Side Windows 10/2009 DM

Applicability:

Model ATR 42-200, 42-300, 42-320, 42-400 and 42-500 aeroplanes, and Model
ATR 72-101, 72-102, 72-201, 72-202, 72-211, 72-212 and 72-212A 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 Airworthiness Directive becomes effective on 22 July 2009.

Background:

A recent event occurred during which the LH forward side glass window of an
ATR 72-212 aeroplane blew out while performing a ground pressure test.

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.

Accordingly, this AD mandates initial and repetitive inspections of LH and RH cockpit forward side glass windows and in case of discrepancies, the replacement of the window(s).

James Coyne
Delegate of the Civil Aviation Safety Authority

21 July 2009