Federal Aviation Administration December 23, 2015 – Federal Register Recent Federal Regulation Documents

We propose to adopt a new airworthiness directive (AD) for all Airbus Model A318, A319, A320, and A321 series airplanes. This proposed AD was prompted by the discovery of corroded circlips in fuel vent protectors (FVP) having a certain part number. This proposed AD would require an inspection to determine the part number and serial number of the FVP, and replacement if necessary. We are proposing this AD to detect and correct corroded circlips. Corroded circlips could lead to failure of the circlips and consequent movement of the FVP, resulting in a reduction of the flame protector capability of the FVP cartridge, which could result in damage to the airplane in case of lightning impact or fire on the ground.

We propose to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 747-400, 747-400D, and 747-400F series airplanes; Model 757 airplanes; and Model 767 airplanes. This proposed AD was prompted by reports of uncommanded autopilot engagement events resulting in incorrect stabilizer trim adjustment during takeoff. This proposed AD would require, depending on the model/configuration for Model 747 airplanes, installing an on-ground stabilizer autotrim inhibit system, doing routine functional testing of the automatic stabilizer trim inhibit system and corrective actions if necessary; for Model 757 airplanes and Model 767 airplanes, installing relays and related wiring to open and close the flight control computer (FCC) analog output that controls the stabilizer trim adjustment, doing routine functional testing of the automatic stabilizer trim inhibit system, and corrective actions if necessary; and for Model 767-300, and -300F series airplanes, installing new operational program software (OPS) into the FCCs. We are proposing this AD to prevent stabilizer mistrim, which could result in a high-speed rejected takeoff and runway overrun, or reduced controllability of the airplane after takeoff due to insufficient pitch control.

We are revising an earlier proposed airworthiness directive (AD) for all Airbus Model A330-200, A330-200 Freighter, A330-300, A340- 200, and A340-300 series airplanes. The NPRM proposed to require inspecting certain trimmable horizontal stabilizer actuators (THSAs) to determine the number of total flight cycles the THSA has accumulated, and replacing the THSA if necessary. The NPRM was prompted by the results of endurance qualification tests on the THSA, which revealed a partial loss of the no-back brake (NBB) efficiency in specific load conditions. This action revises the NPRM by adding airplanes to the proposed applicability, reducing the proposed compliance times for replacing affected THSAs, and revising the definition of a serviceable THSA. We are proposing this supplemental NPRM (SNPRM) to detect and correct premature wear of the carbon friction disks on the NBB of the THSA, which could lead to reduced braking efficiency in certain load conditions, and, in conjunction with the inability of the power gear train to keep the ball screw in its last commanded position, could result in uncommanded movements of the trimmable horizontal stabilizer and loss of control of the airplane. Since these actions impose an additional burden over those proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.