When any heavy maintenance was carried out on our helicopters, the helicopter had to have a maintenance check test flight with the maintenance test pilot and the maintenance test engineer. Heavy maintenance is when any engines, main, intermediate or tail rotor gearbox, main rotor head or main rotor blade, tail rotor blade, flying control equipment and control runs are replaced. Basically, any large maintenance service period that stopped the helicopter flying for more then a month.
The reason for the test flight was to ensure that all systems are serviceable and that the helicopter will remain serviceable when it is inflated to the edge of its flying envelope. The maintenance test pilot is a very experienced pilot, as is the maintenance test engineer.
The flight test can take from as little as 40 minutes up to an hour depending on how many tests are to be carried out on the equipment that has been changed.
After the maintenance crew, of which the flight test engineer could be one, have completed all their repairs and are satisfied that all non aircraft equipment such as ground equipment and tools are removed from the aircraft and returned to their correct storage places, the aircraft is prepared ready for the flight. The test pilot will only accept the aircraft if all the relevant paper work is signed and the ground crew has signed the aircraft fit to fly.
During the test flight the test engineer will ask the pilot to carry out certain maneuvers of the aircraft and when the pilot carries out these maneuvers the flight engineer will check all the communications from the instrument panel and document them for analysis on the aircraft's performance.
When your pilot that is at the end of the test flight he likes to add his little maneuver by dropping the helicopter out of the sky. This is called autorotation, leaving your stomach and its contents about 500 feet higher than your body. You know then that you have a pilot with a sadistic streak to his behavior