The helicopter company's operations, based at Cairns Airport,
Queensland, included passenger charter flights between The Pier, at
Cairns Harbour (4 km SE Cairns Airport) and Green Island (22 km NE
Cairns Airport).
At about 1035 eastern standard time the pilot departed The Pier
for Green Island in a Bell 206 helicopter with six passengers on
board. Because of the likelihood of mechanical turbulence in the
lee of the high terrain south of Trinity Inlet, he initially
tracked via the Cairns Harbour shipping channel. When he reached
the end of the shipping channel, he was unable to see the island
because of rain so he descended from his cruise altitude of 500 ft
to about 300 ft and was then able to see the island about 9 km
ahead. The helicopter arrived at Green Island at about 1045.
At 1130, the pilot departed Green Island for The Pier with six
passengers on board. There was light drizzle falling at the time
but he assessed that conditions in the area were suitable for
flight utilising external visual reference. The pilot again elected
to track via the shipping channel. Clearance to enter the Cairns
Control Zone was not immediately available because of other
traffic, so the pilot conducted a number of orbits in the
helicopter until he was issued with a clearance at about 1139 to
track to The Pier via the shipping channel, not above 500 ft. The
controllers advised the pilot that, within 7-9 km from The Pier,
the cloud base was 800-1,000 ft, with some showers, and visibility
less than 10 km.
As the pilot continued tracking along the shipping channel,
using the channel beacons as track markers, he noticed that the
weather conditions ahead were deteriorating. A short time later, he
descended the helicopter to about 150 ft to keep the water surface
in sight, and reduced speed. At about 1143, the controller
cautioned the pilot that a para-sail was operating in the Cairns
Harbour area. A short time later, the pilot received a request for
his arrival time from the company's office at The Pier. He
responded that he expected to arrive in 5 minutes.
The pilot later reported that by that time the weather
conditions had deteriorated further, he was flying at 50 ft or less
above the water in light to moderate rain and could no longer see
any channel beacons. He selected the windscreen demister on as
condensation had begun to form on the inside surface. He also armed
the inflatable floats that were fitted to the skid-type landing
gear.
At about 1146, the pilot asked the controller for directions to
The Pier. The tower controller advised that The Pier was on a
bearing of 205 degrees M, at a range of 1.5 NM (3 km). At about
that time, in-flight visibility rapidly deteriorated to an extent
where external visual cues were not available. The pilot, noticing
that the altimeter was indicating 100 feet, placed the helicopter
in a gentle descent in an attempt to keep the surface of the water
in sight. The helicopter contacted the water a short time later and
rolled inverted. The pilot and five passengers quickly escaped from
the fuselage to the surface of the water. One passenger was trapped
in the cabin for a number of minutes and did not survive the
accident.
The helicopter was certified for flight under the Visual Flight
Rules and was equipped with a satellite navigation system receiver.
Inflatable floats were attached to the skid type landing gear.
These could be inflated by the pilot in the event of a water
landing. The helicopter was not fitted with a radio altimeter.
The Cairns area was under the influence of south-easterly stream
weather. The Bureau of Meteorology issued an amended aerodrome
forecast for Cairns at 0808 for the 24-hour period from 1000. The
forecast was for an easterly wind at 15 kt, visibility of 9,000 m,
and light rain. Some cloud patches were expected with a base of 800
ft, a broken layer at 1,800 ft, and overcast at 10,000 ft. Periods
of up to 1 hour of heavy rain, scattered cloud at 800 ft, and
broken cloud at 1,500 ft were expected over the forecast
period.
Controllers on duty in the tower indicated that the weather
conditions had been fluctuating significantly and rapidly
throughout the morning. There were periods when conditions met the
criteria for VFR flight. This contrasted with intervals of low
cloud and very heavy rain, amongst the worst conditions they had
seen at Cairns. Radar images and rainfall rates suggested that
visibility in the area of the accident could have been reduced to a
few hundred metres or less. Personnel who were at The Pier at the
time of the accident described the rainfall as torrential, with
visibility as low as one car length.
A weather radar system operated by the Bureau of Meteorology was
located at Saddle Mountain, approximately 11 km north-west of
Cairns Airport. The weather radar data recorded at 1150 showed an
area of moderate rainfall centred over Cairns Harbour, adjacent to
Cairns City. It extended about 5.4 km north-south and about 3.6 km
east-west.
The weather information the controller passed to the pilot was
based on his visual assessment of the weather in Cairns Harbour as
he saw it from the control tower. When the controller issued the
caution to the pilot regarding the para-sail, the radar indicated
altitude of the helicopter was 100 ft.
The Bureau of Meteorology advised that conditions of minimum
visibility at Cairns Airport occurred during the period between
about 1155 and 1210. The recorded rainfall of 5.8 mm between 1150
and 1210 at Cairns Airport was similar to that which would be
encountered in thunderstorms. Although there was an automatic
weather station at Green Island it was not equipped to measure
rainfall.
Examination of recorded Air Traffic Services radar data provided
information on the track, altitude, and ground-speed of the
helicopter for a portion of the flight. The data indicated that the
helicopter was initially tracking via the Cairns Harbour shipping
channel at about 100 kts and an altitude of 200 ft above mean sea
level. At about 7 km from The Pier, the speed gradually decreased
to 55-60 kts and then to below 40 kts. The last recorded speed was
31 kts. The recorded altitude during the final 2 minutes of the
recording was 100 ft, apart from one value of 200 ft. The last
recorded position of the helicopter was 2.4 km north east of The
Pier at about 1148.
Examination of the wreckage confirmed that the helicopter struck
the water in a slight left skid-low, nose-low attitude, and at low
forward and vertical speeds. All seats and safety harnesses
retained their integrity. There was evidence of flexing of the roof
frame on the right forward side of the cabin, immediately behind
the pilot's seat resulting from induced stresses following main
rotor blade contact with the water.
The post mortem examination report stated that the non-surviving
passenger had received a minor head injury that may have had
sufficient effect to prevent her from releasing her safety harness.
The examination established that the passenger died as a result of
drowning. The flexing of the cabin roof occurred above the seating
position of the passenger who was trapped in the helicopter. It is
possible that the roof flexed sufficiently to cause the head injury
to that passenger.
Company ground staff who worked at Green Island conducted a
safety briefing (in Japanese) for the passengers. Those staff had
completed proficiency testing in emergency procedures applicable to
Bell 206 helicopters. The operation of the life jackets, seat
belts, and emergency exit procedures was demonstrated. The
information was summarised on safety information cards (in English
and Japanese) in the helicopter. Each passenger wore a life jacket
contained in a belt-mounted bag.
The pilot said that, after the cabin filled with water, he was
able to easily egress from the helicopter. When he surfaced, he saw
2 or 3 passengers on the opposite (left) side of the upturned
fuselage. He dived and attempted to open the passenger door on the
right side of the helicopter but was unable to do so. When he next
surfaced, there were 5 passengers on the surface. He made a number
of further attempts to open the right side door but could not. Two
passengers had made a few dives from the opposite side of the
helicopter and they brought the injured passenger to the
surface.
The pilot reported that, during an earlier positioning flight to
The Pier, the airspeed indicator (ASI) was not functioning normally
in that it did not indicate above 40 kts. He thought that the fault
was probably due to water in the pitot-static system and expected
it to clear during the flight to Green Island. However, the fault
remained. After landing at Green Island, the pilot sucked then blew
into the pitot head in an attempt to remove any blockage that might
be in the system. Because there were no maintenance facilities on
the island, there was no means of assessing the serviceability of
the instrument before the subsequent flight. The ASI did not
function during the accident flight. The pilot said that he relied
on the ground speed display on the GPS for speed information during
the flight. He did not consider that this had any meaningful affect
on his cockpit workload during the flight.
The opinion of other experienced helicopter pilots spoken to
during the investigation was that the absence of an ASI would have
increased the pilot's workload, particularly in view of the weather
conditions. The erroneous indication on the ASI and the need to
refer to the GPS display would have disrupted the pilot's normal
instrument scan pattern. Further, the GPS displayed ground speed,
not "airspeed", so the speed information the pilot was receiving
was not appropriate to some flight regimes. Civil Aviation Order
Part 20, Section 18 specifies that, for VFR charter operations, a
helicopter must be equipped with a serviceable ASI prior to
take-off.
The company advised that periods of poor weather usually
generated higher demand for helicopter flights because rough seas
and/or rain discouraged some tourists from returning to Cairns by
boat. The pilot indicated that the company expected the pilots to
"give it a go" in the case of bad weather. The company indicated
that pilots were expected to "have a good look before turning back"
during operations away from the departure area, but that there was
no pressure placed on pilots to complete flights in unsuitable
weather conditions.
The pilot was programmed to conduct a number of other flights
later in the day. However, he stated that the schedule had no
bearing on his decision to depart Green Island. The pilot reported
that the usual routes from Green Island to Cairns were via the
shipping channel, or coastal via False Cape. Wind from the south or
south east at about 15 knots or greater caused mechanical
turbulence in the lee of the high terrain on the southern side of
Trinity Inlet. Under such conditions he usually avoided the False
Cape/coastal route because of passenger comfort considerations. The
accident flight was one such instance.
The pilot said that when he departed Green Island, the weather
conditions easily met the VFR criteria. His technique in conditions
of deteriorating visibility was to descend, maintain a visual
reference outside the cockpit and to reduce speed. He applied this
technique on the accident flight. Although visibility was poor, he
continued, in part because of his experience in operating in
similar conditions, but also because the advice from the controller
indicated that the weather would improve as he neared Cairns.
However, the pilot emphasised that he had turned back on a number
of previous occasions because of unsuitable weather conditions.
The pilot stated that, even though he held a night VFR rating it
was not current. In addition, he disliked instrument flight and had
undertaken minimal instrument flying since achieving the rating in
1992. In any event, the helicopter was not certified for IFR
flight. Against this background, he did not consider turning at low
level to fly back towards better conditions as a safe option.
The pilot reported that the visibility conditions during the
return flight from Green Island were the worst that he had
experienced. The sea surface became flat and featureless and
blended completely with the precipitation. By that time, it was too
late to turn around. He reflected that he might have been better
placed by tracking coastal because vegetation and other land
features would have provided a higher level of visual contrast
against the rain/cloud and may have enabled him to safely continue
the flight. Alternatively, he would have been able to land the
helicopter and await passage of the weather.
The aerodrome controller activated the Cairns Airport Emergency
Plan at 1147 after the helicopter disappeared from radar and the
pilot did not respond to radio calls. The police, ambulance,
Queensland Emergency Service (QES) helicopter, and Cairns Aviation
Rescue and Fire Fighting (ARFF) unit responded. The ARFF response
involved dispatching a vehicle towing a trailer mounted rescue boat
to Marlin Marina boat ramp, near The Pier. The vehicle arrived at
the boat ramp at 1204 and the boat reached the crash scene at 1209.
By that time, a tourist vessel and a seaplane were in attendance
and the QES helicopter was overhead. All persons involved in the
accident were placed aboard the tourist vessel and taken to the
Marlin Marina boat ramp. The ARFF later commented that had a
launching facility been available at the Barron River adjacent to
the airport, they would have arrived on the scene much quicker.
