Federal Aviation Administration

Special Airworthiness Information Bulletin

- CE-02-03.pdf

Make:
Air Tractor, Inc.

Model:
Air Tractor, Inc. AT-400
Air Tractor, Inc. AT-500
Air Tractor, Inc. AT-800

Product Type:
Aircraft

Product Subtype:
Small Airplane



Full Text of the SAIB

SPECIAL AIRWORTHINESS INFORMATION BULLETIN Aircraft Certification Service Washington, DC

U.S. Department of Transportation Federal Aviation Administration No. CE-02-03 October 16, 2001

We post SAIBs on the internet at "av-info.faa.gov"
This is information only. Recommendations are not mandatory.

Introduction
This Special Airworthiness Information Bulletin (SAIB) informs you, a registered owner or operator, of Air Tractor AT-400, AT-500, or AT-800 series airplanes affected by Airworthiness Directive (AD) 2001-10-04 R1, of the potential that cracks may still be present even after the two part modification listed in the AD has been performed. The FAA has received comments in response to the issuance of the AD stating that airplanes should be inspected immediately prior to incorporation of the modification. We have had no reports of cracks being found on already modified airplanes.

Background
As a result of an in-service wing failure and subsequent re-evaluation of wing spar fatigue life limits, the FAA issued AD 2001-10-04 R1 to lower aircraft wing spar life limits. This AD had provisions for requesting alternative methods of compliance which allowed owners or operators to repetitively inspect using eddy current the outer most bolt holes of the wing spar at the center splice block. The inspections could be performed at 400 hour intervals.

The National Transportation Safety Board has commented on the AD that the FAA mandate an eddy-current inspection immediately prior to the incorporation of the two-part fix listed in the AD.

The FAA is considering superceding AD 2001-10-04 R1, to mandate this inspection.

Recommendation
The FAA recommends that you ensure that when your airplane is modified, the repair facility performs an eddy-current inspection prior to drilling out the outermost bolt holes in accordance with the appropriate service letter. If a crack is present, it will be easier to detect prior to the modification and will give the repair facility an idea of where to concentrate a post modification inspection to ensure that the entire crack has been removed . Failure to ensure this could result in a significant loss of fatigue life of the wing spar.

For airplanes that have already been modified in accordance with the AD, we recommend that you obtain a letter from the repair facility that performed the modification stating whether or not an inspection of this type was performed. If an inspection has not been performed, we recommend that within 400 hours TIS from the time of the modification, you have an eddy current inspection performed on the two outermost bolt holes on each side of the wing spar center splice.

For Further Information Contact
Rob Romero, Aerospace Engineer, FAA Ft. Worth ACO, 2601 Meacham Blvd, ASW-150, Ft. Worth, TX 76193, telephone: (817) 222-5102, fax: (817) 222-5960, e-mail: robert.a.romero@faa.gov




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