AD/B747/370 Heat Exchanger Shells (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 747 Series Aeroplanes
| AD/B747/370 | Heat Exchanger Shells | 3/2008 |
Applicability: | Boeing Model 747-400 series aeroplanes, as identified in Boeing Service Bulletin (SB) 747-21A2439, Revision 2, dated 24 May 2007. |
Requirement: | 1. Do the actions sspecified in 1a) and 1b) of this AD by accomplishing all the actions specified in the Accomplishment Instructions of the service bulletin. a) Do repetitive general visual inspections to detect discrepancies (i.e., cracks, creases, deformation, deflection, and interference with the rudder and/or elevator cables) of the forward and rear heat exchanger shells of the air distribution system of the crew rest area, and do the applicable corrective actions, until the actions required by 1b) of this AD are done. b) Do an inspection to identify the part number, shop code, and build date of the forward and rear heat exchanger shells of the air distribution system of the crew rest area, and do the applicable corrective actions. Accomplishing the actions in Requirement 1b) ends the repetitive inspections as detailed in Requirement 1a) of this AD. Actions done before the effective date of this AD in accordance with Boeing Alert Service Bulletin 747-21A2439, dated 3 November 2005; or Boeing Service Bulletin 74721A2439, Revision 1, dated 24 July 2006; are acceptable for compliance with the corresponding actions specified in this AD. If a forward heat exchanger shell, part number 65B41601-52, is found installed during the replacement required by AD/B747/232 Amdt 1, or was installed during the inspection required by AD/B747/232 Amdt 1 (AD/B747/232 Amdt 1 refers to Boeing Alert Service Bulletin 747-21A2412, dated 20 January 2000; or Revision 2, dated 2. Do not install a heat exchanger shell having a part number identified in the “Existing Part Number” column of the table specified in paragraph 2.C. of Boeing Service Bulletin 747-21A2439, Revision 2, on any aeroplane. Note: FAA AD 2007-25-19 Amdt 39-15301 dated 30 November 2007 refers. |
Compliance: | 1. At the applicable times specified in the Table 1 of paragraph 1.E. of Boeing Service Bulletin 747-21A2439, Revision 2, except where Boeing Service Bulletin 747-21A2439, Revision 2, specifies a compliance time “after the release date of the service bulletin” or “after the date of Revision 02 of the service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD. The applicable corrective actions must be done before further flight. 2. From the effective date of this AD. |
| This Airworthiness Directive becomes effective on 13 March 2008. | |
Background: | The FAA has received a report of an uncommanded up and down pitch movement of an aeroplane in flight and resistance in the elevator controls on the ground during taxi. The issuing of this AD is intended to prevent cracking and buckling of the forward or rear heat exchanger shell of the air distribution system of the crew rest area, which could result in jamming of the rudder and/or elevator control cables and consequent reduced controllability of the aeroplane. |
Charles Lenarcic
Delegate of the Civil Aviation Safety Authority
21 January 2008
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