AD/Convair/23 Fuselage Stringer and Beltframe Attachment between Stations 140 and 889 (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/23 Fuselage Stringer and Beltframe Attachment between Stations 140 and 889 6/2006

Applicability:

Model 340 and 440 series aircraft, including all such model aircraft converted to turbopropeller power.

Requirement:

1.    For aircraft with more than 52,000 hours time in service, perform an initial detailed visual, above floor level, inspection of the stringers and beltframes for evidence of cracks at all stringer to beltframe attach points between stations 140 and 889; and,

a.     Aircraft certificated at a maximum gross weight of 55,000 lbs or less, and without a main cargo door, perform a detailed visual inspection of all stringer to frame attachment, above and below floor level, for evidence of cracks between stations 140 and 889; and thereafter,

(i)    Perform a detailed visual inspection of all stringer to frame attachment for evidence of cracks below the floor between stations 681 and 889; and,

(ii)   Perform a detailed visual inspection of all stringer to frame attachment for evidence of cracks between stations140 and 889 above the floor and between stations 140 and 681 below the floor.

b.    Aircraft with a main deck cargo door and aircraft certificated at a maximum gross weight of more than 55,000 lbs, perform a detailed visual inspection of all stringer to frame attachment, above and below floor level, for evidence of cracks between stations 140 and 889.

2.    For aircraft with more than 42,000 hours time in service, up to and including 52,000 hours time in service, perform an initial detailed visual, above floor level, inspection of the stringers and beltframes for evidence of cracks at all stringer to beltframe attach points between stations 140 and 889.  Repetitively inspect in accordance with Requirement 1.a. or 1.b.

3.    For aircraft with more than 35,000 hours time in service, up to and including 42,000 hours time in service, perform an initial detailed visual, above floor level, inspection of the stringers and beltframes for evidence of cracks at all stringer to beltframes attach points between stations 140 and 889.  Perform a repetitive detailed visual inspection of all stringer to frame attachment, above and below floor level, for evidence of cracks between stations 140 and 889.  Refer to Requirement 6 for reduction in repetitive inspection interval.

4.    For aircraft with more than 25,000 hours time in service up to and including 35,000 hours time in service, perform an initial detailed visual, above the floor level, inspection of the stringers and beltframes for evidence of cracks at all stringer to beltframe attach points between stations 140 and 889.  Perform a repetitive detailed visual inspection of all stringer to frame attachment, above and below floor level, for evidence of cracks between stations 140 and 889.  Refer to Requirement 6 for reduction in repetitive inspection interval.

5.    For aircraft with less than 25,000 hours time in service, and have not previously been inspected for cracks, perform an initial detailed visual, above the floor level, inspection of the stringers and beltframes for evidence of cracks at all stringer to beltframe attach points between stations 140 and 889.  Perform a repetitive detailed visual inspection of all stringer to frame attachment, above and below floor level, for evidence of cracks between stations 140 and 889.  For those aircraft which have been previously been inspected in accordance with the above initial inspection, accomplish the above repetitive inspections at the intervals required by Requirements 1 through 4.  The first above repetitive inspection must be accomplished before accumulating 28,000 hours time in service or 10,000 additional hours time in service from the above initial inspection, whichever occurs later.

6.    The second inspection, for aircraft affected by Requirements 3 and 4, will be within the 7,500 or 10,000 hours time in service as specified; however, for subsequent inspections, the interval will be based upon the aircraft time in service at the time of the last inspection rather than the total time in service which results in the aircraft reaching the next category.  If the last inspection was accomplished when the aircraft had more than 42,000 hours time in service, all subsequent inspections must be at intervals not to exceed 5,000 hours additional time in service.

If cracks are detected during any inspection, before further flight, repair in accordance with the applicable structural repair manual.

Note:  FAA AD 74-16-01 Amdt 39-1904 refers.

Compliance:

1.    Unless already accomplished, within 300 hours time in service after 8 June 2006, unless accomplished within the last 4,700 hours time in service.

a.     Within 5,000 hours time in service after the initial inspection.

(i)    Within 5,000 hours time in service after the Requirement 1.a. inspection, and thereafter at intervals not to exceed 5,000 hours time in service.

(ii)   Within 7,500 hours time in service after the Requirement 1.a. inspection, and thereafter at intervals not to exceed 7,500 hours time in service.

b.    Within 5,000 hours time in service after the initial inspection, and thereafter at intervals not to exceed 5,000 hours time in service.

2.    Unless already accomplished, within 1,500 hours time in service after 8 June 2006, unless accomplished within the last 3,500 hours time in service.

3.    Unless already accomplished, within 3,000 hours time in service after 8 June 2006, unless accomplished within the last 4,500 hours time in service.  Repetitively inspect thereafter at intervals not to exceed 7,500 hours time in service.

4.    Unless already accomplished, within 3,000 hours time in service after 8 June 2006, unless accomplished within the last 7,000 hours time in service.  Repetitively inspect thereafter at intervals not to exceed 10,000 hours time in service.

5.    Unless already accomplished, within 3,000 hours time in service after accumulating 25,000 hours time in service.  Repetitive inspections must be performed at the intervals required by Requirements 1 through 4.

6.    As specified in Requirement 6.

This Airworthiness Directive becomes effective on 8 June 2006.

Background:

The FAA requires certain actions to prevent loss of structural integrity of the aircraft, due to longitudinal cracks in the stringer or beltframe at the beltframe attach points.

David Villiers
Delegate of the Civil Aviation Safety Authority

11 April 2006