# Proposed AD 99-NM-371-AD: Bombardier Model DHC-8-100, -200, and -300 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2001-17-23
- Action: Supplemental notice of proposed rulemaking; reopening of comment period.
- Published: January 5, 2001, 66 FR 1057
- Comments due: January 30, 2001
- Became: [AD 2001-17-23](https://openairdocs.org/ad/2001-17-23)
- Docket: 99-NM-371-AD
- FR document: 01-342
- Official PDF: https://openairdocs.org/files/sha256/cf/05/cf05995a711fb3311ce9fd862764673acd2585e8e8047b82b84c70a4634a2c2c (from https://www.govinfo.gov/content/pkg/FR-2001-01-05/pdf/01-342.pdf)
- Federal Register: https://www.federalregister.gov/documents/2001/01/05/01-342/airworthiness-directives-bombardier-model-dhc-8-100--200-and--300-series-airplanes
- Page: https://openairdocs.org/proposed/99-NM-371-AD

## Summary

This document revises an earlier proposed airworthiness directive (AD), applicable to certain Bombardier Model DHC-8-100, -200, and -300 series airplanes, that continues to require a one-time detailed visual inspection to detect damage of the ladder plates and access cover areas of the upper surface of the wings, repair, if necessary, and installation of new O-ring seals. That proposal was prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. This new action revises the inspection requirements of the proposed rule by correcting a reference to a repair manual. The actions specified by this new proposed AD are intended to prevent damage of the upper wing ladder plates, which could result in displacement of the adjacent channel seals and consequent reduced lightning strike protection of the fuel tanks.

## Notices in this docket

- Feb 10, 2000: Notice of proposed rulemaking (NPRM). (first notice), FR document 00-3133, comments due Mar 13, 2000 (https://www.federalregister.gov/documents/2000/02/10/00-3133/airworthiness-directives-bombardier-model-dhc-8-100--200-and--300-series-airplanes)
- Jan 5, 2001: Supplemental notice of proposed rulemaking; reopening of comment period., FR document 01-342, comments due Jan 30, 2001 (https://www.federalregister.gov/documents/2001/01/05/01-342/airworthiness-directives-bombardier-model-dhc-8-100--200-and--300-series-airplanes)

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