# Proposed AD FAA-2010-0676: Learjet Inc. Model 45 Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 2010-21-19
- Products: Learjet
- Product type: Aircraft
- Action: Notice of proposed rulemaking (NPRM).
- Published: July 7, 2010, 75 FR 38941
- Comments due: August 23, 2010
- Became: [AD 2010-21-19](https://openairdocs.org/ad/2010-21-19)
- Docket: FAA-2010-0676 (https://www.regulations.gov/docket/FAA-2010-0676, where comments are filed)
- Project: 2010-NM-095-AD
- FR document: 2010-16514
- Official PDF: https://openairdocs.org/files/sha256/ee/3a/ee3a19c3bacc71d8a1dfc5583f6b8b5cae987f2a529b19b6a36afe53e7d90b7c (from https://www.govinfo.gov/content/pkg/FR-2010-07-07/pdf/2010-16514.pdf)
- Federal Register: https://www.federalregister.gov/documents/2010/07/07/2010-16514/airworthiness-directives-learjet-inc-model-45-airplanes
- FAA DRS: https://drs.faa.gov/browse/excelExternalWindow/7B73705EF0498D5886257759004F2B2C.0001
- Page: https://openairdocs.org/proposed/FAA-2010-0676

## Summary

We propose to adopt a new airworthiness directive (AD) for certain Learjet Inc. Model 45 airplanes. This proposed AD would require replacing aluminum fire extinguisher discharge tubes with new, improved tubes; checking the fire extinguisher container for certain serial numbers; replacing fire extinguisher containers that have affected serial numbers; inspecting the pressure indicator on certain fire extinguisher containers for discrepancies; and performing corrective action if necessary. This proposed AD results from a report of accidental discharge of a fire extinguisher container and damage to an aluminum discharge tube. Investigation revealed that following the discharge an inaccurate pressure indication, due to the indicator dial being incorrectly staked, showed that the container was fully charged. We are proposing this AD to prevent inaccurate pressure readings and subsequent damage to the discharge tubes during operation, which could result in failure of the fire extinguisher system and an uncontained fire in an emergency situation.

## Notices in this docket

- Jul 7, 2010: Notice of proposed rulemaking (NPRM). (first notice), FR document 2010-16514, comments due Aug 23, 2010 (https://www.federalregister.gov/documents/2010/07/07/2010-16514/airworthiness-directives-learjet-inc-model-45-airplanes)

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