# Proposed AD 99-NM-15-AD: Learjet Model 31, 31A, 35, 35A, and 60 Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 99-23-19
- Action: Notice of proposed rulemaking (NPRM).
- Published: August 30, 1999, 64 FR 47148
- Comments due: October 14, 1999
- Became: [AD 99-23-19](https://openairdocs.org/ad/99-23-19)
- Docket: 99-NM-15-AD
- FR document: 99-22396
- Official PDF: https://openairdocs.org/files/sha256/20/c0/20c08e9bcd2621608d90dd4cf2e1e06ef761f4da2647c13e887e86d17c02e0f1 (from https://www.govinfo.gov/content/pkg/FR-1999-08-30/pdf/99-22396.pdf)
- Federal Register: https://www.federalregister.gov/documents/1999/08/30/99-22396/airworthiness-directives-learjet-model-31-31a-35-35a-and-60-airplanes
- Page: https://openairdocs.org/proposed/99-NM-15-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Learjet Model 31, 31A, 35, 35A, and 60 airplanes. This proposal would require a visual inspection of the spoiler actuators to determine the serial number of the spoiler actuators; and replacement of the spoiler actuators with new actuators, if necessary. This proposal is prompted by failure of a spoiler actuator piston rod during the first production flight of a Model 60 airplane due to an incomplete heat treatment process. The actions specified by the proposed AD are intended to prevent failure of the spoiler actuator, which could result in the spoiler panel floating and inducing an uncommanded roll of the airplane.

## Notices in this docket

- Aug 30, 1999: Notice of proposed rulemaking (NPRM). (first notice), FR document 99-22396, comments due Oct 14, 1999 (https://www.federalregister.gov/documents/1999/08/30/99-22396/airworthiness-directives-learjet-model-31-31a-35-35a-and-60-airplanes)

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