When the trim interrupt switch is pushed, the autopilot is disengaged and:

• A. All trim systems including the emergency pitch trim system are interrupted.
• B. All trim systems except the emergency pitch trim system are interrupted.
• C. Only autopilot is interrupted.
• D. Trim remains unchanged.

Answer: (B)

Pushing the trim interrupt switch is about quickly stopping automatic trim actions while preserving a safe manual trim path. When you press it, the autopilot is disengaged and the normal trim systems are interrupted so they no longer respond to trim commands. The emergency pitch trim system, however, has its own independent pathway and remains available, giving you a way to manually trim the aircraft if the regular trim system is unavailable. That’s why the effect is that all trim systems except the emergency pitch trim are interrupted.