# Proposed AD 2000-NM-158-AD: Boeing Model 747 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2001-12-21
- Action: Notice of proposed rulemaking (NPRM).
- Published: November 20, 2000, 65 FR 69718
- Comments due: January 4, 2001
- Became: [AD 2001-12-21](https://openairdocs.org/ad/2001-12-21)
- Docket: 2000-NM-158-AD
- FR document: 00-29498
- Official PDF: https://openairdocs.org/files/sha256/bf/b0/bfb0caeeca4651b27d0e5d4013191540859bebee5cfec7f857f9fd38fecf5572 (from https://www.govinfo.gov/content/pkg/FR-2000-11-20/pdf/00-29498.pdf)
- Federal Register: https://www.federalregister.gov/documents/2000/11/20/00-29498/airworthiness-directives-boeing-model-747-series-airplanes
- Page: https://openairdocs.org/proposed/2000-NM-158-AD

## Summary

This document proposes the supersedure of an existing airworthiness directive (AD), applicable to all Boeing Model 747 series airplanes, that currently requires revising the Airplane Flight Manual to include procedures to prevent dry operation of the center wing fuel tank override/jettison pumps and, for certain airplanes, to prohibit operation of the horizontal stabilizer tank transfer pumps in-flight. That AD was prompted by a report indicating that several override/ jettison fuel pumps from the center wing tanks and main tanks had been removed because circuit breakers for the override/jettison fuel pumps were tripped, or low pump output pressure was indicated. For certain airplanes, this action would require installation of improved fuel pumps, which would terminate the requirements of the existing AD. This proposal is prompted by new information received from the fuel pump manufacturer. The actions specified by the proposed AD are intended to prevent contact between the rotating paddle wheel and the stationary end plates within the center wing tank override/jettison fuel pumps or horizontal stabilizer tank transfer pumps, which could cause sparks and/or a hot surface condition and consequent ignition of fuel vapor in the center wing tank or horizontal stabilizer tank during dry pump operation (no fuel flowing).

## Notices in this docket

- Nov 20, 2000: Notice of proposed rulemaking (NPRM). (first notice), FR document 00-29498, comments due Jan 4, 2001 (https://www.federalregister.gov/documents/2000/11/20/00-29498/airworthiness-directives-boeing-model-747-series-airplanes)

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