# Proposed AD 99-NE-34-AD: AlliedSignal Inc. 36-300(A), 36-280(B), and 36-280(D) Series Auxiliary Power Units

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-04-24
- Action: Notice of proposed rulemaking (NPRM).
- Published: September 8, 1999, 64 FR 48723
- Comments due: November 8, 1999
- Became: [AD 2000-04-24](https://openairdocs.org/ad/2000-04-24)
- Docket: 99-NE-34-AD
- FR document: 99-23284
- Official PDF: https://openairdocs.org/files/sha256/d8/2b/d82b8ee5dde7e73d3845ea9ba3a65d687c06a6cbfe08c8c5bf3313b46f454066 (from https://www.govinfo.gov/content/pkg/FR-1999-09-08/pdf/99-23284.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/09/08/99-23284/airworthiness-directives-alliedsignal-inc-36-300a-36-280b-and-36-280d-series-auxiliary-power-units
- Page: https://openairdocs.org/proposed/99-NE-34-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to AlliedSignal Inc. 36-300(A), 36- 280(B), and 36-280(D) series Auxiliary Power Units (APUs). This proposal would require installation of an external load compressor containment shield, or installation of a load compressor impeller with lower stress concentrations. This proposal is prompted by reports of load compressor impeller failures. The actions specified by the proposed AD are intended to prevent an uncontained APU failure and damage to the airplane.

## Notices in this docket

- Sep 8, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-23284, comments due Nov 8, 1999 (https://www.federalregister.gov/documents/1999/09/08/99-23284/airworthiness-directives-alliedsignal-inc-36-300a-36-280b-and-36-280d-series-auxiliary-power-units)

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