Incident Overview
A Vickers Viscount, registration VH-TVA, operated by Trans-Australia Airlines, was destroyed in a crash during a local training flight at Mangalore Airport, Victoria. The aircraft was engaged in a training exercise when, during the takeoff roll on runway 22, after reaching V1 speed, the instructor shut down engine number four (starboard outer) and feathered its propeller to simulate an engine failure. The pilot-in-command continued the takeoff. Shortly after rotation, the aircraft turned to the right and reached a height of 100 feet, at which point it stalled and crashed in flames in a field located less than one kilometer west of the airfield.
Injuries and Damage
Three pilots were killed, and five crew members were injured, three of them seriously. The aircraft was destroyed.
Aircraft Performance Factors
The takeoff was being attempted in the most critical three-engine configuration, with number 4 engine inoperative. In this configuration, with flaps extended 20° and three engines at full power, a minimum speed of 96 knots is necessary to maintain directional control using both rudder and aileron. Below 96 knots, the aircraft cannot be kept from turning. The takeoff safety speed for the conditions at the time of the accident, as given in the flight manual for Viscount VH-TVA, was 106 knots. Trans-Australia Airlines taught its pilots not to lift the aircraft off the ground at speeds below 110 knots in a three-engine takeoff. Calculations indicate that with normal acceleration during a three-engine takeoff, the speed when the aircraft left the runway would have been 85 to 90 knots, which was too low.
Probable Cause
The official finding stated that the cause of the accident was an error of judgment on the part of the pilot-in-command in that he took the aircraft into the air at a speed below the minimum control speed, following loss of directional control during the ground run. Some difficulty in maintaining directional control had been experienced during the takeoff run, but the final loss probably occurred through nose-wheel steering being relinquished as the pilot-in-command took over the controls. A factor probably contributing to this accident was the limited experience of the pilot-in-command on this type of aircraft. Additionally, the report concluded that the injuries sustained by the operating crew indicate that they may have survived if they had been wearing the full safety harness provided for their use in the aircraft.