AD/B767/216 Frequency Converters Medical and Galley Utility Outlets (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.

Boeing 767 Series Aeroplanes

AD/B767/216 Frequency Converters - Medical
and Galley Utility Outlets 2/2006

Applicability:	Model 767-300 series aeroplanes, identified in Boeing Service Bulletin (SB) 767-25-0334, Revision 1, dated 19 June 2003.
Requirement:	1.    If not previously accomplished, either:
a.     Replace the frequency converters used to supply power for medical and galley utility outlets with modified frequency converters in accordance with the Accomplishment Instructions of SB 767-25-0334 Revision 1.
or
b.    Remove and deactivate the frequency converters used to supply power for medical and galley utility outlets, and cap and stow the frequency converter wire bundles, in accordance with paragraphs B.1. through B.6. of the Accomplishment Instructions of SB 767-25-0334 Revision 1.
Actions accomplished before the effective date of this Directive in accordance with SB 767-25-0334, dated 7 November 2002, are acceptable for compliance with Requirement 1.
Later revisions of the above SB, approved by the United States Federal Aviation Administration (FAA) as an Alternate Method of Compliance (AMOC) to FAA AD 2005-24-04, are considered acceptable for compliance with the equivalent Requirements of this Directive.
2.    Frequency converters that have not been modified in accordance with the Accomplishment Instructions of the service bulletin may not be installed as a replacement spare.
Note:  FAA AD 2005-24-04 Amdt 39-14384 refers.
Compliance:	For Requirement 1 - Within 18 months after the effective date of this Directive.
For Requirement 2 - As of the effective date of this Directive.
This Airworthiness Directive becomes effective on 16 February 2006.

Background:

The FAA has received a report indicating that a hard short circuit condition between the output of certain frequency converters and their downstream circuit breakers will produce a continuous output current that could cause the undersized output wiring to overheat when the frequency converters fail to shut off.

This Directive is issued to prevent overheating of the output wiring of the frequency converters, which could result in the failure of a wire bundle and consequent adverse effects on other systems sharing the affected wire bundle.  This Directive requires either the replacing of the frequency converters used to supply power for medical and galley utility outlets with modified frequency converters or their deactivation.

Charles Lenarcic
Delegate of the Civil Aviation Safety Authority

16 December 2005