Collision with water in dark night conditions involving Robinson R22 helicopter, VH-YLY, 6 km south of Cape Tribulation, Queensland, on 7 April 2016

On the morning of 7 April 2016, the pilot of a Robinson Helicopter Company R22 helicopter, registered VH-YLY (YLY) flew from Mareeba to Mossman, Queensland, to join the pilot of another R22 for a fishing trip (Figure 1). Both pilots were qualified to operate the helicopters on private‑category operations by day under the visual flight rules^[1].

The two pilots departed Mossman at about 0800 EST^[2] with a passenger in each of the two‑seat helicopters. The pilots tracked north to Cooktown to refuel then continued northward to Pipon Island, landing at various coastal locations so they and the passengers could do some fishing. At one of the landing sites the pilots were able to fill the helicopter fuel tanks from a drum of fuel.

By the time the helicopters arrived at Pipon Island, the occupants had caught between 20 and 30 kg of fish, which were carried in a non-standard container attached to the left skid of YLY. After spending some time at Pipon Island, the pilots departed separately somewhere between 1600 and 1700 to return to Mossman. The pilots had used GPS route information and local weather conditions, rather than the required aviation Area Forecast,^[3] to decide that they had sufficient fuel and daylight to make it to Mossman, a direct-track distance of 148 NM (274 km).

Figure 1: Location of Pipon Island with Cooktown and Mossman destinations showing position of VH-YLY accident site south of Cape Tribulation. The inset shows Cape Tribulation relative to far north Queensland

Source: Google Earth and modified by ATSB

During the return flight, squalls and headwinds of about 20 kt were encountered that slowed progress and necessitated a landing at Cooktown to refuel. Relative to the other helicopter, YLY was slower likely due to the aerodynamic drag of the skid‑mounted container, the additional weight of the fish, and doors-off operation.

Recorded fuel transaction information showed the time of fuel uplift at Cooktown occurred at 1836. Given last light for Cooktown was calculated to be 1838 (based on ideal conditions), night conditions existed by the time the pilots were ready to depart. Neither pilot was qualified to fly at night or in low visibility conditions that would require instrument flying. Additionally, the helicopters were not equipped with an artificial horizon instrument and lacked other equipment required for flight at night under Australian regulations.

The passenger in YLY reported he was concerned about the available light and weather conditions and queried the pilot’s intention to continue the flight after Cooktown. Without elaborating, the pilot indicated he intended to continue and the flight (direct-track distance of 60 NM) would only take 45 minutes. None of the pilots or the passengers reported any specific reason to arrive at Mossman that evening. The pilots did not discuss staying in Cooktown.

Both helicopters departed Cooktown at about 1840. A witness who observed the departure reported it was getting dark, which was consistent with it being after last light and no moonlight (local moon-set was 1811). Due to the slower speed of YLY, the other helicopter drew ahead. Every 10 minutes or so, the pilot of the lead helicopter, who was the more experienced pilot, checked in with the pilot of YLY by radio.

According to the pilot in the lead helicopter, and as had been discussed, they flew close to the coast intending to keep an outline of the mountains as a visual reference. In ‘bad conditions’, the proposed method was to ensure the altimeter was accurate relative to sea level and use it to fly not below 250 ft above the water. If the conditions got ‘really bad’, in that it got too dark and the outline of the mountains or sight of the water was being affected, the plan discussed between the pilots was to land on a beach. The pilot of the lead helicopter advised they had done this on previous occasions due to bad weather, though only in daylight.

The coastal route between Cooktown and Mossman has few settlements and from halfway, most of the coastline is part of the Cape Tribulation section of the Daintree National Park. It is a remote area and, as such, there is little or no ground lighting.

Initially, the weather conditions were reported to be clear but about 15-20 minutes into the flight, the pilot of the lead helicopter encountered small squalls with a bit of cloud. After passing Cape Tribulation, the pilot of the lead helicopter radioed the pilot of YLY who advised he had just passed the cape and did not report any difficulties.

The passenger in YLY recalled that at one stage the helicopter descended close to the water before the pilot corrected and climbed. He further stated that visibility decreased until it was dark and the pilot dimmed the cockpit lights to reduce glare off the windscreen. The passenger recalled passing the Cape Tribulation campgrounds and was aware that there were people on the beach as indicated by campfires and a spotlight being waved at the passing helicopters.

To the passenger, it got ‘really dark’ and concerning so he suggested landing on the beach. The pilot did not respond verbally but it appeared to the passenger that they might be descending to land. Suddenly the passenger saw the ocean more clearly followed almost immediately by a ‘massive bang’ as the helicopter impacted the water.

When the passenger regained consciousness, he was strapped into the helicopter on the ocean floor. He was able to release himself, reach the surface, and tread water in a heavy swell. Injuries to a leg and arm restricted swimming but the tide carried him to the beach where he was able to make contact with campers and notify the authorities. Campers had heard an impact and already reported it to police.

About 10 minutes after the radio call near Cape Tribulation, the pilot in the lead helicopter tried unsuccessfully to contact the pilot of YLY. He recalled that, at the time, there was light cloud, mist, showers, and strong winds. The lead pilot said he was concerned about YLY and wanted to turn back but was prevented by limited time, strong winds, and marginal visibility. So the pilot continued to Mossman.

A search was mounted but the missing pilot was not found.

Queensland Police with the assistance of specialist divers located the empty wreckage about 400 m seaward of Noah Beach. The wreckage was not recovered but divers examined the wreckage and recorded underwater video imagery, which was provided to the ATSB (Figure 2).

Figure 2: Underwater image of VH-YLY showing significant damage to the nose and belly panel of the helicopter particularly to the right forward section and loss of the cockpit upper portion

Extensive damage to the right side of the helicopter, including the pilot’s seat belt fitting found torn from its mount, indicated a significant right‑side impact with the water. The main rotor blades and transmission were present and similarly damaged. The tailboom was not identified in the footage and it likely became detached during the accident sequence. The damage to the helicopter and rotor system was consistent with powered flight into the water.

A maintenance release had been issued for YLY authorising VFR Day operation only. A check calibration of the aircraft pitot-static system and altimeter was due in October 2015 and had yet to be certified as complete. As such, the accuracy of the airspeed indicator, vertical speed indicator and altimeter was not assured. A review of the helicopter logbooks did not find any reference to installation of the container to the left skid.

Based on the reported loading of YLY, on departure from Cooktown for Mossman the helicopter was estimated to be at least 35 kg over the maximum gross weight limitation. Although there was no weight and balance data for the skid-mounted container, the longitudinal and lateral centre of gravity were estimated to be outside limits on departure or as fuel was consumed.

Although some of the flying that day included flight over water, the pilots and passengers did not wear life jackets. This was contrary to the regulatory requirement for the occupants of single‑engine aircraft being operated beyond gliding/autorotation distance of land and while below 2,000 ft.

According to the applicable area forecast required for flight planning, in the area of operation east of the ranges and coast, there would be isolated showers with associated low cloud and reduced visibility. The wind was expected to be from the east to south-east at 15 to 20 kt. From 2300, isolated areas of low cloud were expected east of the ranges and coast. This was broadly consistent with the aerodrome forecasts for Cooktown and Cairns, except that the showers and low cloud were due at Cairns from 1700.

The closest official weather observation site to the accident location was at Low Isles, 15 NM (28 km) to the south. At the approximate time of the accident, the wind was from the south-east at 20 kt. No precipitation was recorded during the hour before and after the accident. The extent of cloud coverage was not measured at the site.

The recorded imagery from the Cairns weather radar showed a small area of light rain inland near Cape Tribulation and patches of light to moderate rain off the coast no closer than 15 NM (28 km).

For aviation purposes, night is defined as the period of darkness from last light (end of evening civil twilight) to first light (beginning of morning civil twilight). At last light, in ideal conditions, there will be enough light from the sun for large objects to be seen but no detail. As time passes, light from the sun further diminishes to reach a point where it is insufficient to allow a horizon to be seen at sea level. This point (end of evening nautical twilight) at Cape Tribulation was calculated to be 1919 but high terrain to the west would tend to make it effectively earlier.

The time of the accident was estimated to be 1930, which was about 10 minutes after end of evening nautical twilight.

__________

1. Visual Flight Rules (VFR) are a set of regulations which allow a pilot to only operate an aircraft in weather conditions generally clear enough to allow the pilot to see where the aircraft is going.
2. Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.
3. Area forecast (ARFOR): routine forecasts for designated areas and amendments when prescribed criteria are satisfied. Australia is subdivided into a number of forecast areas.

From the evidence available, the following finding is made with respect to the collision with water of a Robinson Helicopter Company R22 helicopter, registered VH-YLY that occurred near Cape Tribulation, Queensland, on 7 April 2016. These findings should not be read as apportioning blame or liability to any particular organisation or individual.

Contributing factor

• The pilot of YLY, who was only qualified to operate in day-VFR conditions, departed on a night flight and continued towards the destination in deteriorating visibility until inadvertently allowing the helicopter to descend into water.

Sources of information

The sources of information during the investigation included the:

• surviving occupants of the two helicopters
• Cairns Forensic Crash Unit, Queensland Police
• the Bureau of Meteorology
• the Civil Aviation Safety Authority (CASA)
• Airservices Australia
• Geoscience Australia

References

ATSB (2013), Avoidable Accidents No. 7. Visual flight at night accidents: What you can’t see can still hurt you, ATSB, Canberra, Australia.

Robinson Helicopter Company (Rev. 1994), Safety Notice SN-13 Do not attach items to the skids.

Robinson Helicopter Company (Rev. 1994), Safety Notice SN-18 Loss of visibility can be fatal.

Robinson Helicopter Company (Rev. 1994), Safety Notice SN-26 Night flight plus bad weather can be deadly.

Robinson Helicopter Company (2001), Safety Notice SN-37 Exceeding approved limitations can be fatal.

Submissions

Under Part 4, Division 2 (Investigation Reports), Section 26 of the Transport Safety Investigation Act 2003 (the Act), the Australian Transport Safety Bureau (ATSB) may provide a draft report, on a confidential basis, to any person whom the ATSB considers appropriate. Section 26 (1) (a) of the Act allows a person receiving a draft report to make submissions to the ATSB about the draft report.

A draft of this report was provided to the other R22 pilot and CASA.

Submissions were received from the other R22 pilot and CASA. The submissions were reviewed and where considered appropriate, the text of the report was amended accordingly.