# Airworthiness Directives; Raytheon (Beech) Model 400, 400A, 400T, and MU-300-10 Airplanes
> **Rule** · Final rule. · Published 1999-10-18 · Effective 1999-11-22 · 64 FR 56163
## Document
- **Document number:** 99-26867
- **Category:** airworthiness
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 64 FR 56163
- **Publication date:** 1999-10-18
- **Effective date:** 1999-11-22
- **FAA docket:** Docket No. 96-NM-209-AD
## Abstract

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Raytheon (Beech) Model 400, 400A, 400T, and MU-300-10 airplanes, that currently requires a revision to the Airplane Flight Manual (AFM) to provide pilots with special operating procedures during icing conditions. This amendment adds a requirement to modify the airplane ice protection system. This amendment also removes Model MU-300 airplanes from the applicability of the existing AD. This amendment is prompted by the development of a modification that will positively address the unsafe condition. The actions specified by this AD are intended to prevent uncommanded nose-down pitch at certain flap settings during icing conditions.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/10/18/99-26867/airworthiness-directives-raytheon-beech-model-400-400a-400t-and-mu-300-10-airplanes)
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