The selection of the wrong destination on a global positioning system (GPS) unit probably contributed to a pilot’s spatial disorientation in the seconds before his Eurocopter AS355 F2 crashed in dark night conditions after departing from a South Australia island, the Australian Transport Safety Bureau (ATSB) says.
The 16,000-hour pilot and his two passengers — members of a film crew working on a television documentary — were killed in the crash 145 km (78 nm) north of Marree, South Australia, at 1902 local time Aug. 18, 2011. The helicopter was destroyed.
In its final report, released in November 2013, the ATSB said that the pilot probably became spatially disoriented seconds after he intentionally began a gentle right turn at 1,500 ft (Figure 1).
“Factors contributing to the disorientation included dark night conditions, high pilot workload associated with establishing the helicopter in cruise flight and probably attempting to correct the fly-to point in a GPS unit, the pilot’s limited recent night flying and instrument flying experience, and the helicopter not being equipped with an autopilot.”
The report said that the accident flight was one in a series that began Aug. 17 in Sydney, New South Wales. The helicopter landed that evening in Parachilna, South Australia, and departed at 0716 the next day for the first filming flight of the day. Other flights in the Lake Eyre region followed, and the helicopter landed early in the afternoon at Muloorina Station, 48 km (26 nm) north of Marree, where luggage was offloaded and the helicopter was refueled (Figure 2). The helicopter left Muloorina Station at 1418, and, after the first stop, flew to an island in the Cooper Creek inlet, landing around 1715. Plans called for the crew to return to Muloorina Station after completing their work on the island.
When the helicopter departed from the island site at 1859, it “initially climbed vertically while moving rearwards … most likely to maintain a visual reference to the campfire, which was the only available ground light source,” the report said.
At 500 ft, the helicopter turned left to a heading of 035 degrees, then climbed to 1,500 ft. The helicopter flew east, then northeast, “contrary to what [witnesses] expected, as they understood that the crew were returning to their accommodation at Muloorina Station (96 km [52 nm] away on a southerly bearing),” the report said.
One witness radioed the helicopter pilot to question the flight path, but there was no response. Investigators could not determine whether the helicopter’s radio had been turned on, but they noted that, as expected, there were no radio communications with air traffic services during the brief flight.
The helicopter was not equipped with a flight data recorder or a cockpit voice recorder, and neither was required. Data recovered from the helicopter’s GPS unit showed that the helicopter entered a shallow right turn and, 12 seconds later, began a downward spiral that continued for 38 seconds, until the helicopter crashed into the ground at high speed and a bank angle of about 90 degrees.
The report said witnesses at the departure site — members of a tour group on the island — had watched the helicopter’s descent, “followed by a fireball and an orange glow.” They notified authorities and began a search, locating the wreckage about 3 km (1.6 nm) east-northeast of the departure site at 2040.
The report said that the initial departure path, with the turn at 500 ft, was “consistent with the pilot using one or both of the helicopter’s … GPS units … and tracking to a destination selected prior to departure.”
The 035-degree outbound track “can best be explained by the pilot having selected an incorrect destination on one or both of the GPS units,” the report added, noting that data for another planned landing site, which had been programmed into at least one GPS, called for the helicopter to fly within about one degree of the 035-degree track.
“Errors in selecting a waypoint on a GPS unit are not uncommon, and are potentially more likely to occur during preflight planning in low-light situations,” the report said. Even if the pilot did not hear the radioed question about his departure path, “the data-entry error would probably have become evident to the pilot at some stage during the climb or soon after reaching 1,500 ft. … It is likely that the right turn after reaching 1,500 ft was intentional, and it was initiated in order to correct an unintended problem with the initial departure track to the northeast.”
In the last seconds of the flight, “given that the pilot was probably manipulating the flight controls but not apparently recognising the descent and increasing bank angle in sufficient time to recover, it is likely that he was spatially disoriented,” the report said. “The circumstances of the flight included limited perceptual cues of a problem, elevated workload and potential for distraction, a pilot with limited instrument flying recency and an aircraft with no autopilot. These types of factors have been associated with many previous spatial disorientation accidents, including accidents involving a gradually increasing bank angle and descent over a significant time period.”
Owner and Chief Pilot
The accident pilot was the owner, managing director and chief pilot of the third-party operator hired by the helicopter’s owner, a Sydney media organization, to take charge of its helicopter operations. The pilot had provided services to the media organization for more than 20 years, the report said.
He had obtained a commercial pilot license for helicopters in 1977, while he was a pilot for the Australian Army, and a night visual flight rules (VFR) helicopter rating (which included approval for the use of nondirectional beacons and VHF omnidirectional radios) in 1979. He had never held a civil command instrument rating, which had more stringent requirements and was required for night aerial work and charter flying, or GPS navigation approval. He was endorsed in several helicopter types, including the AS355.
According to the last entry in the pilot’s logbook, not quite two months before the accident, he had 16,353 flight hours, most of them in helicopters. That flight time included 484 hours at night, including 3.4 nighttime hours in the previous year.
Accident investigators found “no relevant records” for the period between June 27, 2011, and Aug. 17, and family members and colleagues could not remember whether he had flown during those months.
To carry passengers at night, the pilot was required to have flown three night takeoffs and landings in the previous 90 days; there was a record of one night landing, at the operator’s base in Sydney, during that period.
A May 2009 operator’s proficiency check was the pilot’s last recorded biennial flight review, although an April 2010 proficiency check was “conducted to the same standard and by the same approved testing officer as the May 2009 check,” the report said.
The pilot turned 60 in October 2010 and was required by civil aviation regulations to complete an annual proficiency check or flight review in order to serve as pilot-in-command on any passenger-carrying commercial flight. Because the last proficiency check had been conducted April 27, 2010, he was ineligible to conduct commercial flights with passengers after April 27, 2011.
The 2010 proficiency flight included 0.7 hours of night flying, and the check pilot found no problems with the pilot’s performance. The flight did not include dark night conditions, however, and the check pilot noted that the accident pilot’s next check flight “should address night flight in marginal VMC [visual meteorological conditions] to revise instrument scan skills.”
Previous check flights had revealed “no significant concerns” about the pilot’s instrument flight skills.
Because the operator’s flights were conducted by single pilots, the accident pilot’s colleagues had limited opportunity to observe his performance, the report said. Media personnel who had flown with him said that their operations rarely required night flights, although one previous passenger reported a flight that had involved about 30 minutes of night flying and no problems.
“Overall, it was considered likely that most of the pilot’s night flying in recent years would have been near built-up areas with a significant amount of terrestrial lighting,” the report said.
The report said that the week before the accident, the pilot had been vacationing in an area located three time zones away from Sydney, but he returned five days before his flight duties began Aug. 17 and was considered well rested. He flew 7.5 hours on Aug. 17, landing at 1637, and began flying at 0716 the next morning, after a period of time off that gave him an opportunity for eight hours of sleep. Before the accident flight, he had conducted eight flights in 4.3 flight hours.
The pilot had a Class 1 medical certificate and had undergone an aviation medical assessment, including a routine stress electrocardiogram, in November 2010; no problems were found.
The helicopter was manufactured in 1988 and registered in Australia in 1989. When the accident occurred, it had accumulated 11,920 hours total time. It was maintained in accordance with manufacturer requirements and certified for day and night charter operations under night VFR. The pilot had told maintenance personnel during the flight to the Lake Eyre region that the helicopter was operating normally.
The helicopter had two GPS units — a Garmin GPS400W on the center pedestal below the instrument panel and a portable Garmin GPSMAP 495, which was mounted above the instrument panel on the center pillar of the windscreen.
The helicopter also had a radar altimeter system that indicated height above ground level up to 2,000 ft; however, at more than 30 degrees of bank and more than 20 degrees of pitch, the device displayed an altitude greater than the actual height above ground level.
The helicopter was not equipped with a ground proximity warning system, and one was not required. The helicopter also lacked an autopilot — a factor that the report said “increased the likelihood that an unusual attitude would develop during the right turn” — but, an autopilot was not required for night VFR flight.
Light From a Campfire
Members of the island tour group said there were no clouds and minimal winds before the takeoff, about one hour after sunset, and they classified the ambient illumination level as “dark.”
“Apart from the tour group’s campfire on the island, there were no other known sources of terrestrial lighting cues available in the vicinity of the helicopter’s flight path,” the report said, adding that the moon was not visible at the time of the crash, and stars would have been the only source of light.
A pilot who had flown in the area several years earlier for the same media organization said the stars had not been visible because of glare from the instrument lights, and there was no visible horizon. “The pilot said the darkness was ‘frightening,’ and he had to fly the helicopter by flight instruments for the flight to Marree,” the report said.
The departure site lacked markings, lighting and wind indicators that were specified by Civil Aviation Advisory Publication (CAAP) 92-2 (1) as necessary for night operations, the report said, noting that the operator’s operations manual told pilots to comply with the CAAP.
The report credited the operator with using a system of risk control for night VFR flight that in some cases exceeded regulatory requirements. However, the operator “did not effectively manage the risk associated with operations in dark night conditions,” the report said.
In addition, the operator did not require a written risk assessment before each flight.
The Australian Civil Aviation Safety Authority (CASA) said, in a May 2011 safety trend indicator assessment of the operator, that it was advising the chief pilot to adopt a formal safety management system and to consider implementing a fatigue risk management system, although neither was required.
Noting that VFR flights were permitted in dark night conditions — “effectively the same as instrument meteorological conditions” — the report said the ATSB had identified the following safety issues:
- The absence of “sufficient requirements for proficiency checks and recent experience to enable flight solely by reference to instruments”; and,
- The absence of requirements for “autopilots and similar systems that are in place” for flights conducted under instrument flight rules.
In response, CASA noted that pilot licensing rules that took effect in December 2013 require pilots to “demonstrate competency during biennial night [VFR] assessments.” The agency said it would provide additional guidance material on night VFR operations, consider related rules changes, clarify its definition of nighttime “visibility” and promulgate a regulation requiring either an autopilot or an IFR-qualified two-pilot crew in passenger-carrying night air transport flights in helicopters.
The report said that another issue involving the operator’s risk control systems was rendered moot because the company stopped conducting flight operations after the accident.
This article is based on ATSB Transport Safety Report AO-2011-102, “VFR Flight Into Dark Night Involving Aerospatiale AS355F2, VH-NTV.” Nov. 14, 2013.
LOC-I in Helicopters
Preventing, recognizing and responding to rotorcraft upsets must evolve in a manner similar to the prevention of loss of control–in flight (LOC-I ) involving large commercial jets, according to Geoff Connolly, a captain and consultant experimental test pilot, FlightExperimentations. Speaking at the Royal Aeronautical Society’s 8th International Flight Crew Training Conference in London in September 2013, he said, “LOC-I in helicopters is most often because of spatial disorientation–positional awareness. Very often, a combination of … factors [aggravated by pilot errors in airspeed and power control] can lead to loss of control and subsequently [to] semi-controlled flight into the terrain.”
Various LOC-I causal factors have been proposed, but a few have been cited repeatedly in U.K. investigations, he said, adding, “The lack of automatic stabilization or autopilots, particularly in VFR [visual flight rules] operations, is a particular factor.”
He identified commonalities among seven of many reports he reviewed, suggesting that future mitigations be more integrated from an LOC-I perspective. The commonalities were degraded visual environment (including dark night conditions and low visibility in weather); visual illusions (“a particular problem offshore where things can be very black,” he said); human factors; crew resource management, including pilot monitoring; cockpit design/human-machine interface; system performance/handling qualities; depth of pilot understanding of automation/lack of automation; and unexpected transitions from visual meteorological conditions (VMC) to instrument meteorological conditions (IMC).
“I have sat in simulators and seen the startle effect on an experienced pilot sitting alongside me who inadvertently enters IMC,” Connolly said. “He’s not expecting it, and the startle effect is real.”
One of the helicopter LOC-I threats, incipient vortex ring state, requires attention to fundamental rotary-wing aerodynamics. On the plotted lift/drag curve for a helicopter, “we can come all the way back up the curve, as speed reduces, until we end up in the hover,” he said. “So we have a large area of our flight envelope where we can be in a low airspeed–high power demand area. … Vortex ring state [is] effectively the helicopter equivalent of the [airplane wing] stall. … The good news: We can recover. And, funny old thing, recovery is stick forward, select an accelerative attitude, allow the airspeed to increase and you will get out of the condition.”
Discussing the seven reports with possible LOC-I elements, Connolly noted that sometimes pilots with the highest levels of flight experience failed to recognize or recover from upset situations, including incipient vortex ring state. In a 1991 offshore ship-to-helideck approach by two such pilots in night VMC, the helicopter lost airspeed and descended at a high rate into the water.1 In a 1992 case, the crew was flying a shuttle between oil rigs at night in snow showers, rough seas and with the wind gusting 55 kt while turning downwind (with possible downdraft effects).2 “The pilot flying reduced power and raised the nose, airspeed reduced to zero and the rate of descent started to increase; full power failed to stop the aircraft entering the water,” he said.
A 2006 accident involved a night approach to an oil rig platform in poor visibility and rain (ASW, 1/09). “The copilot … got into an unusual attitude and lost control. … The aircraft was 12 degrees nose down, 20 degrees right roll and at 126 kt when it went into the water,” Connolly said. In a 2009 accident, the helicopter flew into the sea in a near-level attitude during visual approach to an oil rig in poor visual conditions at night (ASW, 11/11). “There were no stabilized approach criteria — something we’ve learned from our fixed-wing brethren,” he said.
Although an accident on Aug. 23, 2013, in the Shetland Islands, North Sea, remains under investigation, Connolly said that preliminary facts from official sources — “the airspeed reduced, the aircraft started to descend and then ended up descending rapidly into the water” — imply a need to consider LOC-I scenarios (ASW, 10/13).
Mitigation efforts so far — such as revised weather limitations for night operations under VFR; electronic flight instrument systems; synthetic vision aids (including head-up displays and forward-looking infrared) to counteract visual illusions; new autopilot capabilities and limitations; enhanced helideck lighting standards; standard operating procedures for pilots (including stabilized approach criteria); and greater fidelity in simulation modeling — should be viewed as steps toward even better operating methodology and flight procedures. He also proposed practicing hands-on flying skills and scenarios involving “disorientation, loss of control, decision making and judgment — thinking about energy management and vortex ring.”
“Our synthetic training devices have improved immensely,” Connolly added. ”There are still deficiencies in the mathematical modeling of some emergencies — like vortex ring, tail rotor failures and so on. But they are what we’ve got, and we must use them as best as we can. … We should be educating ourselves and going beyond just training. … We need improved and greater depth of knowledge of automated systems.”
— Wayne Rosenkrans
- Australian Bureau of Air Safety Investigation (BASI). “Puma SA 330J Helicopter VH-WOF, Mermaid Sound, Western Australia, 12 May 1991.” BASI Report B/915/1020.
- AAIB. “Report on the accident to AS 332L Super Puma, G-TIGH, near the Cormorant ‘A’ platform, East Shetland Basin [North Sea], on 14 March 1992.” Aircraft Accident Report 2/93. 1993.