AD/AT-6/1 Wing Attach Angles (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.

Rockwell (N American) & Autair (Noorduyn)
AT-6, BC-1A, SNJ, T-6G, Harvard, & AT-16 Series Aeroplanes

AD/AT-6/1 Wing Attach Angles 8/2005 TX

Applicability:

Models AT-6 (SNJ-2), AT-6A (SNJ-3), AT-6B, AT-6C (SNJ-4), AT-6D (SNJ-5), AT-6F (SNJ-6), BC-1A, Harvard (Army AT-16), SNJ-7, and T-6G aircraft; all serial numbers.

Requirement:

1.    Perform a fluorescent penetrant inspection of all inboard and outboard, upper and lower wing attach angles (except for the nose angles) of both wings for cracks, in accordance with the Appendix to FAA AD 2005-12-51.

If cracks are found, replace cracked angles before further flight.

2.    Report to FAA the results of the initial Requirement 1 inspection even if no damage is found and even if the inspection was previously accomplished.  The report sheet (containing contact information) is part of the FAA AD.

3.    The aircraft may be operated to position to a home base, hangar, maintenance facility, etc., for the purpose of doing the required inspection, with the issue of a special flight permit, subject to the following limitations:

a.     Acrobatic manoeuvres are prohibited.

b.    Flight into known or forecast moderate or severe turbulence is prohibited.

c.     Day visual flight rules (VFR) operation only.

d.    Single pilot operation only (passengers prohibited).

Note 1:  FAA Emergency AD 2005-12-51 refers.

Note 2:  The FAA posts Emergency ADs on the internet at

Compliance:

1.    Before further flight after 11 June 2005, unless previously accomplished within the last 15 hours time in service.  Inspect thereafter at intervals not to exceed 200 hours time in service.

2.    Within 7 days after the Requirement 1 inspection or within 7 days after 11 June 2005, whichever occurs later.

3.    The aircraft may be operated up to 10 hours time in service provided the flight(s) occur(s) no later than 30 days after 11 June 2005.  This is a one-time provision.
This Airworthiness Directive becomes effective on 10 June 2005.
Background:	The FAA received a report of a Model SNJ-6 (AT-6F) aircraft crash that occurred on 9 May 2005, resulting in two fatalities.  The ensuing investigation revealed a large fatigue crack in the failed lower inboard wing attach angle.  The aircraft was used for hire in aerobatic training.  Fatigue cracking may occur in the upper and/or lower attach angles that join the centre and outer wings, and, if allowed to progress, could result in wing failure and consequent loss of control of the aircraft.

David Villiers
Delegate of the Civil Aviation Safety Authority

9 June 2005