AD/Convair/1 Horizontal Stabiliser Attachment Fitting Lugs (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.

Kelowna Flightcraft (General Dynamics/Convair) Series Aeroplanes

AD/CONVAIR/1 Horizontal Stabiliser Attachment Fitting Lugs 4/2006

Applicability:

All model 340, 440, and all such model aircraft converted to turbopropeller power.

Requirement:

1.    Perform a visual inspection of the upper and lower, forward and aft, horizontal stabiliser attachment fitting lugs in accordance with the Accomplishment Instructions of General Dynamics, Convair Division, Service Bulletin
640 (340D) 55-3A, Revision 1.

2.    Perform an ultrasonic inspection of the upper and lower, forward and aft, horizontal stabiliser attachment fitting lugs in accordance with the Accomplishment Instructions of Service Bulletin 640 (340D) 55-3A.

If cracks are found during any above inspection, replace with a new part before further flight.

3.    Install bushings in the horizontal stabiliser attachment fitting lug holes in accordance with the Accomplishment Instructions of Service Bulletin
640 (340D) 55-3A.

4.    Perform an internal visual inspection for cracks in the horizontal stabiliser attachment fittings, upper and lower, forward and aft, and associated structure outboard of the lugs and butt rib in the area surrounding the fasteners, in accordance with the Accomplishment Instructions of Service Bulletin
640 (340D) 55-4 Revision 1.  Inspect for evidence of loose rivets or fasteners in the stabiliser attachment fittings with particular attention given to those just outboard of the butt rib which fasten the upper forward fittings to the spar web and rail.

If cracks are found in the stabiliser attachment fittings or associated structure, and/or if loose fasteners are detected in the stabiliser attachment fitting: replace the fitting with a new part, repair structure, and/or replace the fasteners in accordance the Accomplishment Instructions of Service Bulletin
640 (340D) 55-4, before further flight.

5.    Perform an x-ray inspection for cracks in the upper forward and upper aft horizontal stabiliser attachment fittings in the area outboard of the lugs in accordance with the Accomplishment Instructions of Service Bulletin
640 (340D) 55-4.  Only the four upper fittings are required to be x-ray inspected as they are the most highly loaded in tension and therefore most susceptible to fatigue cracking.  If cracks are found, replace with a new part before further flight.

6.    Replace the first three steel rivets outboard of the butt rib through the two forward upper horizontal stabiliser attachment fittings in accordance with the Accomplishment Instructions of Service Bulletin 640 (340D) 55-4.

Note:  FAA AD 82-19-02 Amdt 39-4458 refers.

Compliance:

1.    Within 250 hours time in service after 13 April 2006, unless previously accomplished within 450 hours before 13 April 2006; thereafter at intervals not to exceed 700 hours time in service.

2.    Within 250 hours time in service after 13 April 2006, unless previously accomplished within 1150 hours time in service before 13 April 2006; thereafter at intervals not to exceed 1400 hours time in service.

3.    Unless already accomplished, within 10,000 hours time in service after 16 September 1982 (the effective date of FAA AD 82-19-02).  Continue to inspect after bushing replacement in accordance with Requirement 1 and 2.

4.    Within 250 hours time in service after 13 April 2006, unless previously accomplished within 450 hours time in service before 13 April 2006; thereafter at intervals not to exceed 700 hours time in service.

5.    Within 250 hours time in service after 13 April 2006, unless previously accomplished within 1150 hours time in service before 13 April 2006; thereafter at intervals not to exceed 1400 hours time in service.

6.    Unless already accomplished, within 10,000 hours time in service after 16 September 1982 (the effective date of FAA AD 82-19-02).  Continue to inspect after rivet replacement in accordance with Requirement 4 and 5.

This Airworthiness Directive becomes effective on 13 April 2006.

Background: The FAA requires certain inspections to prevent the possible loss of the horizontal stabiliser due to failure of the stabiliser attachment fittings (part numbers
340-8510150 and 340-8510151), caused by fatigue cracks.

David Punshon
Delegate of the Civil Aviation Safety Authority

1 March 2006