# Proposed AD 99-NM-18-AD: Boeing Models 737-100, -200, -300, - 400, and -500 Series Airplanes; and Model 727-100 and -200 Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 99-24-06
- Action: Notice of proposed rulemaking (NPRM).
- Published: May 10, 1999, 64 FR 24964
- Comments due: June 24, 1999
- Became: [AD 99-24-06](https://openairdocs.org/ad/99-24-06)
- Docket: 99-NM-18-AD
- FR document: 99-11615
- Official PDF: https://openairdocs.org/files/sha256/19/dd/19dd7935fdef3a6f19f9335014c1d1c99b67082ab2e242880fa86ff268f9bcb6 (from https://www.govinfo.gov/content/pkg/FR-1999-05-10/pdf/99-11615.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/05/10/99-11615/airworthiness-directives-boeing-models-737-100--200--300---400-and--500-series-airplanes-and-model
- Page: https://openairdocs.org/proposed/99-NM-18-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Models 737-100, - 200, -300, -400, and -500 series airplanes, and all Models 727-100 and -200 series airplanes. This proposal would require a one-time inspection to determine the presence and condition of the breather plug in each fuel tank boost pump; and either installation of a new plug or replacement of the boost pump with a new pump, if necessary. This proposal is prompted by a report that breather plugs were missing from fuel tank boost pumps. The actions specified by the proposed AD are intended to prevent possible ignition of fuel vapor in the fuel boost pump, which could result in a fuel tank explosion in the event of a boost pump internal failure.

## Notices in this docket

- May 10, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-11615, comments due Jun 24, 1999 (https://www.federalregister.gov/documents/1999/05/10/99-11615/airworthiness-directives-boeing-models-737-100--200--300---400-and--500-series-airplanes-and-model)

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