# Proposed AD 99-NM-186-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 99-23-08
- Action: Notice of proposed rulemaking (NPRM).
- Published: August 30, 1999, 64 FR 47144
- Comments due: October 14, 1999
- Became: [AD 99-23-08](https://openairdocs.org/ad/99-23-08)
- Docket: 99-NM-186-AD
- FR document: 99-22393
- Official PDF: https://openairdocs.org/files/sha256/c6/3e/c63e3b69c286a1bc21443997c0168f3915394716a49d122e0b48261037bd550a (from https://www.govinfo.gov/content/pkg/FR-1999-08-30/pdf/99-22393.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/08/30/99-22393/airworthiness-directives-mcdonnell-douglas-model-dc-9-10--20---30--40-and--50-series-airplanes-and
- Page: https://openairdocs.org/proposed/99-NM-186-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain McDonnell Douglas Model DC-9-10, -20, -30, -40, and -50 series airplanes, and C-9 (military) airplanes. This proposal would require a one-time general visual inspection to detect certain discrepancies in the wiring of the fuel quantity indicating system (FQIS) in the forward cargo compartment; and corrective actions, if necessary. This proposal is prompted by a report indicating that several discrepancies were found in the wiring of the FQIS due to maintenance or alteration practices. The actions specified by the proposed AD are intended to prevent excessive electrical energy from entering the fuel tanks through the FQIS wiring, which could result in a potential ignition source in the fuel tanks.

## Notices in this docket

- Aug 30, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-22393, comments due Oct 14, 1999 (https://www.federalregister.gov/documents/1999/08/30/99-22393/airworthiness-directives-mcdonnell-douglas-model-dc-9-10--20---30--40-and--50-series-airplanes-and)

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