The pilot of an Enstrom 280C helicopter was to conduct about 30
joyflights during the afternoon. Each flight was planned to last
for about 3 minutes and carry two passengers. The flights commenced
at approximately 1330 Eastern Standard Time and were to be finished
by last light, which was 1758. The aircraft was refuelled twice
during the afternoon, with the helicopter shut down and fuel
transferred from jerrycans. The second refuelling was completed at
about 1745.
Passengers then boarded the helicopter for the twenty-seventh
flight of the afternoon. Witnesses reported that transition from
the hover to forward flight appeared normal, and that they had then
stopped watching the helicopter. A short time later they heard the
sound of impact. The helicopter had struck a tree prior to
impacting the ground. The occupants were not injured.
The pilot reported that the helicopter's engine did not appear
to gain full power during the transition and climb and that he
deliberately did not correct a minor out of balance situation to
avoid overpitching the rotor. He assessed that there was sufficient
engine power available to clear the trees and continue the flight.
The area beyond the trees was clear so that if a problem occurred
after he cleared the trees, he could have allowed the helicopter to
descend to gain performance and continue the flight. The pilot said
that the engine turbo-overboost light did not illuminate as it had
done during previous departures.
The air temperature was about 28 degrees C. Witnesses reported
that the wind at ground level had been calm during the day. The
pilot reported that about 20 minutes before the accident,
Archerfield Tower, which was about eight kilometres east of the
accident location, reported the surface wind at Archerfield to have
been easterly at 12 knots. Throughout the afternoon, movement of
the tree tops had indicated a steady wind. However, the pilot said
that he did not have an opportunity immediately before the takeoff
to confirm the wind strength.
The pilot held a Commercial Pilot (Helicopter) Licence and had
accumulated 200 hours total flying experience and 130 hours on the
Enstrom.
A comprehensive examination of the engine found nothing that
might have prevented it from operating normally.
In line with a normal diurnal wind variations, it is possible
that the wind was beginning to die at the time of the accident
(dusk). Because of the added fuel, the helicopter's all up weight
was higher than for the previous takeoff. Both of these changes,
either separately or in combination, would have increased the power
required for the helicopter to maintain the previously flown
departure profile. The pilot would have needed to adjust the
departure path or transition technique to account for the decreased
performance available. The investigation was unable to determine if
maximum engine power had been achieved.
Because no fault could be found with the engine, it was
considered likely that the departure path or transition technique
had not been sufficiently adjusted to account for the changed
conditions. The pilot's low level of experience and the repetitive
nature of the flying may have also been factors in the
accident.