# Airworthiness Directives; Air Tractor, Inc. Model AT-501 Airplanes
> **Rule** · Final rule; request for comments. · Published 2006-04-17 · Effective 2006-04-21 · 71 FR 19628
## Document
- **Document number:** 06-3614
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 71 FR 19628
- **Publication date:** 2006-04-17
- **Effective date:** 2006-04-21
- **FAA docket:** Docket No. FAA-2006-23647
## Abstract

The FAA is adopting a new airworthiness directive (AD) to revise AD 2002-11-05, which applies to certain Air Tractor, Inc. (Air Tractor) AT-400 series and Models AT-501, AT-802, and AT-802A airplanes. AD 2002-11-05 establishes a safe life for the wing lower spar cap. Since we issued AD 2002-11-05, we have received reports of cracks found prior to the established safe life on AT-400 series airplanes and on Model AT-802A airplanes. We are issuing separate AD actions for AT-400 series and Models AT-802 and AT-802A airplanes to address the unsafe condition of those airplanes. This AD retains the actions required in AD 2002-11-05 for Model AT-501 airplanes and removes AT-400 series and Models AT-802 and AT-802A airplanes from the applicability of AD 2002-11-05.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2006/04/17/06-3614/airworthiness-directives-air-tractor-inc-model-at-501-airplanes)
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