# Proposed AD 2001-CE-36-AD: Air Tractor, Inc. AT-400, AT-500, and AT-800 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2002-11-05
- Products: Air Tractor
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: December 27, 2001, 66 FR 66823
- Comments due: February 15, 2002
- Became: [AD 2002-11-05](https://openairdocs.org/ad/2002-11-05)
- Docket: 2001-CE-36-AD
- FR document: 01-31555
- Official PDF: https://openairdocs.org/files/sha256/b3/36/b336f3b0294750b676612920fc12449ed55db0e9cb56900a8ee8034802becdca (from https://www.govinfo.gov/content/pkg/FR-2001-12-27/pdf/01-31555.pdf)
- Federal Register: https://www.federalregister.gov/documents/2001/12/27/01-31555/airworthiness-directives-air-tractor-inc-at-400-at-500-and-at-800-series-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/D32BEAC368996A2486256B2F0068E1BA.0001
- Page: https://openairdocs.org/proposed/2001-CE-36-AD

## Summary

This document proposes to supersede Airworthiness Directive (AD) 2001-10-04 R1, which lowered the safe life for the wing lower spar cap on certain Air Tractor, Inc. (Air Tractor) AT-400, AT-500, and AT-800 series airplanes. AD 2001-10-04 R1 resulted from numerous reports of cracks in the \3/8\-inch bolthole of the wing lower spar cap on the affected airplanes. This proposed AD would maintain the safe life and add a requirement for you to eddy--current inspect the wing lower spar cap immediately prior to the replacement/modification in order to detect and correct any crack in a bolthole before it extends to the modified center section of the wing and repair that crack or replace the wing section. This proposed AD would also further reduce the safe life for certain AT-400 and AT-500 series airplanes that incorporate or have incorporated Marburger Enterprises, Inc. winglets. These winglets are installed in accordance with Supplemental Type Certificate (STC) SA00490LA. The actionsspecified by this proposed AD are intended to prevent fatigue cracks from occurring in the wing lower spar cap before the originally-established safe life is reached. Fatigue cracks in the wing lower spar cap, if not detected and corrected, could result in the wing separating from the airplane during flight.

## Notices in this docket

- Dec 27, 2001: Notice of proposed rulemaking (NPRM). (first notice), FR document 01-31555, comments due Feb 15, 2002 (https://www.federalregister.gov/documents/2001/12/27/01-31555/airworthiness-directives-air-tractor-inc-at-400-at-500-and-at-800-series-airplanes)

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