Study of tail rudder deflection angles for stabilizing the twin turboprop small passenger aircraft in critical flight due to one engine failed condition

An aircraft must have durability, whether for normal flight condition and for a critical flight condition. One of the critical flight conditions of a twin-engines aircraft is the failure of one engine while the aircraft is cruising. The aircraft with only one live engine on will still have enough power to generate thrust. However, the aircraft will experience a moment couple due to the thrust on the remaining engine that makes the aircraft to yaw. This yaw effect must be compensated by the flight control in order to maintain a stable flight condition. The rudder as one of the flight control systems manages the aircraft yaw motion. So, therefore the rudder deflection angle must be set properly as a treatment to overcome the moment force of the live engine. Study to determine best approximated optimum rudder deflection angle setting were conducted to get the figures of how the counter side forces generated on the rudder can maintain a stable flight. The result of the study can be applied as important guidance for a pilot to control the aircraft in a critical flight condition due to one engine fails. Considerations on the strength and integrity of the rudder structure especially at the hinge pivot points between the dynamic and the static parts are taken account as well.