AD/EMB-145/15 APU Exhaust Duct Cracks (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.

Embraer EMB-135 and EMB-145 Series Aeroplanes

AD/EMB-145/15 APU Exhaust Duct Cracks 8/2008

Applicability:

Embraer EMB-145( ) aircraft, serial numbers 145601, 145614 and 145626, fitted with APU cowling exhaust assembly P/N 145-52460-401, which forms part of APU cowling assembly P/N 145-52979-401.

Requirement:

1.    Carry out a detailed visual inspection with a magnifying glass of 8X minimum in all APU exhaust gusset strap area, with emphasis in the spot weld points.  If any crack is found, replace the exhaust duct with another bearing or cut the damaged duct P/N 145-50348-001 after the gusset strap area, preserving all not affected welded points.

2.    Repeat the inspection until the exhaust duct is replaced with another bearing with a different P/N not affected by this AD.

The detailed instructions and procedures to accomplish this AD are described in the Embraer Alert Service Bulletin No. 145-49-A023, original issue, or further revisions approved by the CTA.

Note:  SERVIÇO PÚBLICO FEDERAL DEPARTAMENTO DE AVIAÇÃO CIVIL AD 2002-11-02 dated 28 November 2002 refers.

Compliance:

For Requirement 1 - Within 50 flight hours after the effective date of this AD, unless previously accomplished.

For Requirement 2 - At intervals not exceeding 50 flight operating hours.

This Airworthiness Directive becomes effective on 31 July 2008.

Background:

Two cases of cracks in the non-silenced APU exhaust duct extension have been found which could lead to a duct separation during flight.

James Coyne
Delegate of the Civil Aviation Safety Authority

20 June 2008