# Proposed AD 99-CE-51-AD: Twin Commander Aircraft Corporation 600 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-02-30
- Action: Notice of proposed rulemaking (NPRM).
- Published: October 12, 1999, 64 FR 55191
- Comments due: December 1, 1999
- Became: [AD 2000-02-30](https://openairdocs.org/ad/2000-02-30)
- Docket: 99-CE-51-AD
- FR document: 99-26576
- Official PDF: https://openairdocs.org/files/sha256/db/8b/db8bd7bb4037e17d23ece9064e4b27b5c76f5ff4f7404ab3a5075c5a7c152eda (from https://www.govinfo.gov/content/pkg/FR-1999-10-12/pdf/99-26576.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/10/12/99-26576/airworthiness-directives-twin-commander-aircraft-corporation-600-series-airplanes
- Page: https://openairdocs.org/proposed/99-CE-51-AD

## Summary

This document proposes to adopt a new airworthiness directive (AD) that would apply to all Twin Commander Aircraft Corporation (Twin Commander) 600 series airplanes. The proposed AD would require revising the Airplane Flight Manual (AFM) to include requirements for activation of the airframe pneumatic deicing boots. The proposed AD is the result of reports of in-flight incidents and an accident that occurred in icing conditions where the airframe pneumatic deicing boots were not activated. The actions specified by the proposed AD are intended to assure that flightcrews activate the pneumatic wing and tail deicing boots at the first signs of ice accumulation. This action will prevent reduced controllability of the aircraft due to adverse aerodynamic effects of ice adhering to the airplane prior to the first deicing cycle.

## Notices in this docket

- Oct 12, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-26576, comments due Dec 1, 1999 (https://www.federalregister.gov/documents/1999/10/12/99-26576/airworthiness-directives-twin-commander-aircraft-corporation-600-series-airplanes)

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