Suicide by pilot

Suicide by pilot is an aviation event in which a pilot deliberately crashes or attempts to crash an aircraft in a suicide attempt, sometimes to kill passengers on board or people on the ground. This is sometimes described as a murder–suicide.
Prevention.
U.S. regulations require at least two flight crew members to be in the cockpit at all times for safety reasons, to be able to help in any medical or other emergency, including intervening if a crew member tries to crash the plane. Following the deliberate crash of Germanwings Flight 9525 on March 24, 2015, some European, Canadian and Japanese airlines adopted a two-in-cockpit policy as did all Australian airlines for aircraft with 50 or more passenger seats.