# Proposed AD 99-NM-185-AD: Airbus Model A330 and A340 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2000-06-08
- Action: Notice of proposed rulemaking (NPRM).
- Published: December 14, 1999, 64 FR 69674
- Comments due: January 13, 2000
- Became: [AD 2000-06-08](https://openairdocs.org/ad/2000-06-08)
- Docket: 99-NM-185-AD
- FR document: 99-32370
- Official PDF: https://openairdocs.org/files/sha256/75/9a/759a7559cabdd6d5c8e1d5766ef77453dd35b2cd69e12863e183b42b8ec29367 (from https://www.govinfo.gov/content/pkg/FR-1999-12-14/pdf/99-32370.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/12/14/99-32370/airworthiness-directives-airbus-model-a330-and-a340-series-airplanes
- Page: https://openairdocs.org/proposed/99-NM-185-AD

## Summary

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Airbus Model A330 and A340 series airplanes, that currently requires repetitive operational tests of the override mechanism of the trimmable horizontal stabilizer (THS) to determine if the system functions correctly; and corrective action, if necessary. This action would require replacement of existing flight control primary computers (FCPC) with improved FCPC's, which would terminate the repetitive operational tests. This proposal is prompted by the issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by this proposal are intended to prevent uncommanded movement of the THS, which could result in reduced controllability of the airplane.

## Notices in this docket

- Dec 14, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-32370, comments due Jan 13, 2000 (https://www.federalregister.gov/documents/1999/12/14/99-32370/airworthiness-directives-airbus-model-a330-and-a340-series-airplanes)

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