Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all British Aerospace (Jetstream) Model 4101 airplanes. This proposal would require inspection for cracking of the mounting brackets of the hydraulic hand pump at the frame attachment flanges, replacement of any cracked bracket with a new bracket, replacement of all bolts and nuts with new bolts and nuts, and installation of a particular `D' packer. This action is necessary to prevent failure of these brackets, which could result in inability to extend the landing gear in an emergency situation where the main hydraulic system is lost. This action is intended to address the identified unsafe condition.