# Airworthiness Directives; Hamilton Sundstrand Power Systems T-62T-46C12 Auxiliary Power Units
> **Rule** · Final rule. · Published 2009-10-16 · Effective 2009-11-20 · 74 FR 53159
## Document
- **Document number:** E9-24396
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 74 FR 53159
- **Publication date:** 2009-10-16
- **Effective date:** 2009-11-20
- **FAA docket:** Docket No. FAA-2009-0247
## Abstract

The FAA is adopting a new airworthiness directive (AD) for Hamilton Sundstrand Power Systems T-62T-46C12 auxiliary power units (APUs). This AD requires upgrading the software in the APU full- authority digital controller (FADEC) from software version 02.01.000 to version 03.00.000. This AD results from two reports of APU compartment explosions due to over-fueling of the APU at low revolutions-per-minute during the start sequence. We are issuing this AD to prevent over- fueling of the APU during the start sequence, which could lead to fuel explosions, injury, and damage to the APU and the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/2009/10/16/E9-24396/airworthiness-directives-hamilton-sundstrand-power-systems-t-62t-46c12-auxiliary-power-units)
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