Summary
This document proposes the adoption of a new airworthiness directive (AD) that is applicable to certain Boeing Model 747 series airplanes. This proposal would require an inspection of the flap drive transmission of the trailing edge flaps at positions 2 and 7 to determine if a wound-spring torque brake is installed, and corrective action, if necessary. This action is necessary to prevent damage to the flap system, adjacent systems, or structural components; or excessive skew of the trailing edge flap, which could result in flap asymmetry and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition.