# Proposed AD 98-NM-70-AD: de Havilland Model DHC-8-100, -200, and -300 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 97-20-10 R1
- Action: Notice of proposed rulemaking (NPRM).
- Published: June 16, 1998, 63 FR 32771
- Comments due: July 16, 1998
- Became: [AD 97-20-10 R1](https://openairdocs.org/ad/97-20-10-R1)
- Docket: 98-NM-70-AD
- FR document: 98-15885
- Official PDF: https://openairdocs.org/files/sha256/19/f4/19f4d7c981f5f2e1755c8fa97b4d629ff491d9658703d0f8bd64b837967561be (from https://www.govinfo.gov/content/pkg/FR-1998-06-16/pdf/98-15885.pdf)
- Federal Register: https://www.federalregister.gov/documents/1998/06/16/98-15885/airworthiness-directives-de-havilland-model-dhc-8-100--200-and--300-series-airplanes
- Page: https://openairdocs.org/proposed/98-NM-70-AD

## Summary

This document proposes to revise an existing airworthiness directive (AD), applicable to certain de Havilland Model DHC-8-100, - 200, and -300 series airplanes, that currently requires modification of the attitude and heading reference systems (AHRS). That AD was prompted by a report of loss of power to both AHRS's during flight due to a faulty terminal block to which the signal ground for the AHRS's is connected. The actions specified by that AD are intended to prevent simultaneous power loss to both AHRS's, which could result in reduced controllability of the airplane. This action would reduce the applicability of the existing AD.

## Notices in this docket

- Jun 16, 1998: Notice of proposed rulemaking (NPRM). (first notice), FR document 98-15885, comments due Jul 16, 1998 (https://www.federalregister.gov/documents/1998/06/16/98-15885/airworthiness-directives-de-havilland-model-dhc-8-100--200-and--300-series-airplanes)

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