# Airworthiness Directives; Boeing Model 747-400 Series Airplanes
> **Rule** · Final rule; request for comments. · Published 1999-10-26 · Effective 1999-11-10 · 64 FR 57553
## Document
- **Document number:** 99-27561
- **Category:** airworthiness
- **Manufacturer:** Boeing Model 747-400 Series
- **Type:** Rule
- **Action:** Final rule; request for comments.
- **Citation:** 64 FR 57553
- **Publication date:** 1999-10-26
- **Effective date:** 1999-11-10
- **FAA docket:** Docket No. 99-NM-178-AD
## Abstract

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-400 series airplanes. This action requires an inspection of the crew rest area heat exchangers to detect deflection or interference with the flight control cables; and various follow-on actions. This action also requires replacement of certain nutplate attachment rivets that attach the heat exchangers to the airframe with stronger rivets. This amendment is prompted by a report of interference between insulation blankets adjacent to the heat exchangers and flight control cables. The actions specified in this AD are intended to prevent a reduction in maximum rudder and elevator surface deflection due to the separation of heat exchangers from the body frame, which could result in reduced controllability of the airplane.

## Source
- [Federal Register document](https://www.federalregister.gov/documents/1999/10/26/99-27561/airworthiness-directives-boeing-model-747-400-series-airplanes)
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