EASA SIB NM-15-03
Boeing Aeroplanes — Inadvertent Actuation of Flight Deck Controls
Summary
The FAA Special Airworthiness Information Bulletin SAIB: NM-15-03 addresses an airworthiness concern regarding inadvertent actuation of flight deck controls on all Boeing transport category airplanes, specifically highlighting the Boeing 737-700 and 737-500 models. The bulletin informs operators about the risk of confusing the rudder trim switch with the flight deck door control switch, which can lead to unintended aircraft control inputs during flight.
What Changed
This bulletin introduces recommendations for procedural and configuration changes to reduce the risk of inadvertent activation of flight deck controls. It emphasizes standardizing aisle stand configurations within operator fleets and suggests specific placements for the rudder trim and flight deck door control switches to minimize confusion. Boeing also developed new design guidelines for aisle stand layouts in production airplanes to enhance switch differentiation.
Why It Matters
This information is critical for aviation professionals as inadvertent activation of flight controls can lead to significant flight safety risks, including loss of control incidents. Operators, maintenance, and compliance teams must understand and mitigate these risks through proper procedures and cockpit configuration to ensure safe aircraft operation and prevent negative transfer errors between different Boeing 737 models.
What To Do
Operators should review and, if necessary, revise their flight deck procedures to prevent misuse of the flight deck door control switch and ensure positive control of the door. They should also assess and standardize aisle stand configurations across their fleets, placing the rudder trim switch in the center column aft position and the flight deck door control switch in the far right column aft position. The FAA recommends implementing both procedural and configuration changes to effectively mitigate the risk.