# Proposed AD 98-NM-324-AD: Bombardier Model DHC-8-311 and -315 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 99-21-27
- Action: Notice of proposed rulemaking (NPRM).
- Published: August 12, 1999, 64 FR 43959
- Comments due: September 13, 1999
- Became: [AD 99-21-27](https://openairdocs.org/ad/99-21-27)
- Docket: 98-NM-324-AD
- FR document: 99-20891
- Official PDF: https://openairdocs.org/files/sha256/37/87/3787a4df3b3eec9bcfabeb68d3ff4165cddd4630865c3fe440068c3ca630c7d7 (from https://www.govinfo.gov/content/pkg/FR-1999-08-12/pdf/99-20891.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/08/12/99-20891/airworthiness-directives-bombardier-model-dhc-8-311-and--315-series-airplanes
- Page: https://openairdocs.org/proposed/98-NM-324-AD

## Summary

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-311 and -315 series airplanes, that currently requires replacement of the nitrogen cylinder assemblies that inflate the airplane's ditching dams with improved nitrogen cylinder assemblies. This action would expand the applicability of the existing AD. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent failure of the ditching dams to inflate fully during an emergency water landing, which could result in water entering the airplane.

## Notices in this docket

- Aug 12, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-20891, comments due Sep 13, 1999 (https://www.federalregister.gov/documents/1999/08/12/99-20891/airworthiness-directives-bombardier-model-dhc-8-311-and--315-series-airplanes)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.