# Airworthiness Directives; AlliedSignal Inc. (Formerly Textron Lycoming) Model ALF502R-5 and ALF502R-3A Turborfan Engines
> **Rule** · Final rule. · Published 1999-07-19 · Effective 1999-09-17 · 64 FR 38557
## Document
- **Document number:** 99-18099
- **Category:** airworthiness
- **Manufacturer:** AlliedSignal Inc. (Formerly Textron Lycoming) Model ALF502R-5 and ALF502R-3A Turborfan
- **Type:** Rule
- **Action:** Final rule.
- **Citation:** 64 FR 38557
- **Publication date:** 1999-07-19
- **Effective date:** 1999-09-17
- **FAA docket:** Docket No. 98-ANE-42-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), applicable to AlliedSignal Inc. Model ALF502R-5 and ALF502R-3A turbofan engines, that requires incorporation of an improved fan core inlet anti-ice system. This amendment is prompted by reports of uncommanded reduction of engine thrust (rollback) and loss of thrust control in icing conditions. The actions specified by this AD are intended to prevent ice accretion on the fan core inlet stator vane surfaces, which can result in engine rollback and loss of thrust control in icing conditions.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/07/19/99-18099/airworthiness-directives-alliedsignal-inc-formerly-textron-lycoming-model-alf502r-5-and-alf502r-3a)
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