# Proposed AD 97-NM-71-AD: Mitsubishi Heavy Industries Ltd. Model YS-11 and YS-11A Series Airplanes

- Type: Proposed airworthiness directive (not in force)
- Status: Became AD 98-13-13
- Action: Notice of proposed rulemaking (NPRM).
- Published: April 9, 1998, 63 FR 17346
- Comments due: May 26, 1998
- Became: [AD 98-13-13](https://openairdocs.org/ad/98-13-13)
- Docket: 97-NM-71-AD
- FR document: 98-9339
- Official PDF: https://openairdocs.org/files/sha256/ac/48/ac48f0c815d593b57d2d7f26b409ba8290481521e231469631812d05be5c75a7 (from https://www.govinfo.gov/content/pkg/FR-1998-04-09/pdf/98-9339.pdf)
- Federal Register: https://www.federalregister.gov/documents/1998/04/09/98-9339/airworthiness-directives-mitsubishi-heavy-industries-ltd-model-ys-11-and-ys-11a-series-airplanes
- Page: https://openairdocs.org/proposed/97-NM-71-AD

## Summary

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Mitsubishi Model YS-11 and YS- 11A series airplanes. This proposal would require revising the airplane flight manual (AFM) to prohibit positioning the power levers below the flight idle stop. This proposal is a result of incidents and accidents involving airplanes equipped with turboprop engines in which the propeller beta was used improperly during flight. The actions specified by the proposed AD are intended to prevent loss of airplane controllability or engine overspeed with consequent loss of engine power caused by the power levers being positioned below the flight idle stop while the airplane is in flight.

## Notices in this docket

- Apr 9, 1998: Notice of proposed rulemaking (NPRM). (first notice), FR document 98-9339, comments due May 26, 1998 (https://www.federalregister.gov/documents/1998/04/09/98-9339/airworthiness-directives-mitsubishi-heavy-industries-ltd-model-ys-11-and-ys-11a-series-airplanes)

---
OpenAirDocs.org is an independent research project of [Contrail Labs](https://contraillabs.com/). It is not affiliated with the FAA or the NTSB. Source documents are U.S. government works in the public domain.