AD 94-26983

Abstract

This amendment supersedes an existing airworthiness directive (AD), applicable to Hamilton Standard 14RF, 247F, 14SF, and 6/5500/F (formerly Hamilton Standard/British Aerospace 6/5500/F) series propellers, that currently requires initial and repetitive inspections of the propeller control unit (PCU) servo ballscrew internal spline (BIS) teeth for wear, and replacement, if necessary, of PCU servo BIS assemblies. This amendment increases the repetitive inspection interval from 500 to 1,500 hours time in service (TIS) since last inspection for propellers that have a ballscrew quill damper installed. This amendment is prompted by the availability of improved hardware that restricts quill motion and enhances the lubrication of the BIS and significantly reduces BIS wear. The actions specified by this AD are intended to prevent inability to control the propeller blade angle due to tooth wear in the PCU servo BIS assembly.

Applicability · by US fleet size

• CONSTRUCCIONES AERONAUTICAS SA CN-235 4 tails

Compliance instructions

Required actions, compliance times, parts/serial numbers and methods of compliance are in the Federal Register publication — not paraphrased here. Read AD on Federal Register ↗