# Proposed AD 96-NM-91-AD: McDonnell Douglas Model DC-9-10, -20, - 30, -40, and -50 Series Airplanes and C-9 (Military) Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 96-21-01
- Action: Notice of proposed rulemaking (NPRM).
- Published: July 10, 1996, 61 FR 36307
- Comments due: August 19, 1996
- Became: [AD 96-21-01](https://openairdocs.org/ad/96-21-01)
- Docket: 96-NM-91-AD
- FR document: 96-17537
- Official PDF: https://openairdocs.org/files/sha256/a2/32/a232b8772dc781aa798c0f1031e83dabe1177cb2ee5338958dd8b10370bbbfb3 (from https://www.govinfo.gov/content/pkg/FR-1996-07-10/pdf/96-17537.pdf)
- Federal Register: https://www.federalregister.gov/documents/1996/07/10/96-17537/airworthiness-directives-mcdonnell-douglas-model-dc-9-10--20---30--40-and--50-series-airplanes-and
- Page: https://openairdocs.org/proposed/96-NM-91-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9 series airplanes and C-9 (military) airplanes. This proposal would require either replacement or modification of the hydraulic damper assembly. This proposal is prompted by reports indicating that insufficient damping of the hydraulic shimmy damper in the main landing gear (MLG) can allow high torsional vibration to occur. The actions specified by the proposed AD are intended to prevent such vibration, which can damage the MLG assembly and lead to its collapse.

## Notices in this docket

- Jul 10, 1996: Notice of proposed rulemaking (NPRM). (first notice), FR document 96-17537, comments due Aug 19, 1996 (https://www.federalregister.gov/documents/1996/07/10/96-17537/airworthiness-directives-mcdonnell-douglas-model-dc-9-10--20---30--40-and--50-series-airplanes-and)

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