# Proposed AD 99-NM-25-AD: Airbus Model A319, A320, A321, A330, and A340 Series Airplanes Equipped With AlliedSignal RIA-35B Instrument Landing System Receivers

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 99-21-28
- Action: Notice of proposed rulemaking (NPRM).
- Published: August 17, 1999, 64 FR 44663
- Comments due: September 16, 1999
- Became: [AD 99-21-28](https://openairdocs.org/ad/99-21-28)
- Docket: 99-NM-25-AD
- FR document: 99-21333
- Official PDF: https://openairdocs.org/files/sha256/3c/7d/3c7ddeee0f6adb92c3ac4c5d2e6b74fd44c97da186f43c045e62b90e10b69d89 (from https://www.govinfo.gov/content/pkg/FR-1999-08-17/pdf/99-21333.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/08/17/99-21333/airworthiness-directives-airbus-model-a319-a320-a321-a330-and-a340-series-airplanes-equipped-with
- Page: https://openairdocs.org/proposed/99-NM-25-AD

## Summary

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Airbus Model A319, A320, A321, A330, and A340 series airplanes, that currently requires revising the Airplane Flight Manual (AFM) to require the flightcrew to discontinue use of any Instrument Landing System (ILS) receiver for which a certain caution message is displayed. It also requires, for certain airplanes, replacing any faulty ILS receiver with a new, serviceable, or modified unit, and provides for optional terminating action for the AFM revisions. That amendment was prompted by a pilot's report of errors in the glide slope deviation provided by an ILS receiver. This action would require accomplishment of the previous optional terminating action. The actions specified by this proposal are intended to detect and correct faulty ILS receivers and to ensure that the flightcrew is advised of the potential hazard of performing ILS approaches using a localizer deviation from a faulty ILS receiver, and advised of the procedures necessary to address that hazard. An erroneous localizer deviation could result in a landing outside the lateral boundary of the runway.

## Notices in this docket

- Aug 17, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-21333, comments due Sep 16, 1999 (https://www.federalregister.gov/documents/1999/08/17/99-21333/airworthiness-directives-airbus-model-a319-a320-a321-a330-and-a340-series-airplanes-equipped-with)

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