The pilot of a Eurocopter AS350 B3 had never operated from a helideck at sea when he took off from an Antarctic supply ship and descended below a low cloud layer to fly as low as 30 ft above the Antarctic. The helicopter crashed into pack ice, killing all four people aboard, the French Bureau d’Enquêtes et d’Analyses (BEA) says.
In its final report on the Oct. 28, 2010, accident, the BEA said that the probable cause was “the decision to undertake the flight and to continue it in unfavourable meteorological conditions in a hostile environment that offered few alternatives to the plan of action.”
The decision “probably resulted in the loss of visual references in whiteout conditions,” the report added.
Three contributing factors were cited:
- The “context of the campaign” — the pilot’s awareness of the urgency of the delivery of personnel and equipment to an Antarctic research base — which “gave particular importance to achieving the mission’s goals.”
- The “absence of operational documentation” with specific instructions for flights in an area of the Antarctic known by the French as Adélie Land, where the French Dumont d’Urville scientific research base is located.
- The failure of the operator, SAF Helicopteres, to submit to the regulatory authority the section of its operations manual dealing with instructions for Adélie Land flights.
In addition, the report said that the pilot’s use of anti-seasickness medication, which had a sedative effect, “may have contributed to the accident.”
The AS350 and a second helicopter were on the ship l’Astrolabe, along with replacement personnel and materials destined for the Dumont d’Urville base. The original plan called for l’Astrolabe to proceed to a point about 43nm (80 km) from the base, where supplies and personnel would be transferred to the two helicopters for the remainder of the journey.1
However, the ship’s propeller was damaged on Oct. 27, when it was 207 nm (129 km) from the Dumont d’Urville base. The vessel was unable to proceed. “For maintenance purposes, the ship had to turn back no later than the morning of 31 October,” the report said.
“On 28 October, the pilots of the two helicopters on board the ship agreed to transport the passengers and any equipment that could fit into the cabin to the Dumont d’Urville base,” the report said. “The flights would relieve the personnel from the base for the first time after nine months’ winter residence.”
The first helicopter took off from the ship’s helideck about 1630 local time, carrying supplies and three passengers. About 1645, the accident helicopter departed with three passengers, including a maintenance technician, and additional supplies.
Soon after 1750, the accident pilot made a 360-degree turn, descending from 2,500 ft to about 800 ft and telling the other pilot that the maneuver was intended to allow him to fly the helicopter below the cloud layer. About 1800, he made a second 360-degree turn, flying between 300 ft and 50 ft and reducing the helicopter’s speed from 130 kt to 40 kt.
At 1809, the first helicopter landed at Dumont d’Urville.
At 1815, the last data point was recorded for the accident helicopter, showing it at 30 ft. Two minutes earlier, the report said, “two speeds recorded 30 seconds apart were less than 8 kt.”
At 1828, the alarm from the helicopter’s emergency locator beacon was detected. Because of adverse weather, the wreckage was not found until two days later, when the crew of an Australian search and rescue Lockheed P-3 Orion located the crash site. The bodies of the pilot and his three passengers were recovered by helicopter.
Because of risks associated with the breakup of the pack ice, a close examination of the wreckage was not possible. An aerial observation by the pilot of the other SAF helicopter, however, indicated that it had been moving at a low vertical speed and a high horizontal speed when it struck the ice, the report said.
The pilot, 36, had accumulated 3,122 flight hours, including 1,664 hours in type. In 1998, he received a commercial pilot license, which was converted to a flight crew license in 2009. He also had a flight instructor rating and type ratings in the AS350, AS355 SP and SA316/319/315. He had a Class 1 medical certificate and, at one time, had held an instrument flight rules rating, obtained in Canada, but it expired in 2000. Before the accident, he had flown two hours in the previous 30 days and 130 hours in the previous six months.
The pilot of the first helicopter told investigators the accident pilot had “expressed his concerns … regarding taking off from and landing on the helideck,” the report said. “He had never previously performed these maneuvers.”
The accident pilot was hired in 2004 by SAF Helicopteres, which operates worldwide, including in “hostile environments,” the report said. SAF was awarded a contract in August 2010 by the Paul-Émile Victor French Polar Institute (IPEV), operator of the Dumont d’Urville base and a second Antarctic scientific research base, to provide helicopter transportation of personnel and supplies several times over the coming year and to station one AS350 B3, a pilot and a mechanic at Dumont d’Urville for short flights throughout the year.
SAF had planned to amend its operations manual — as required for renewal of its aircraft operator certificate — to include “instructions specific to missions conducted in Adélie Land,” the report said. When the accident occurred, the changes had not been made, and the new operations base at Dumont d’Urville had not been reported.
The report noted two points from the SAF Helicopteres operations manual: that pilots “will fly at 500 ft above the ground or above water” and that “since no flight is to be performed at altitudes of less than 500 ft AGL [above ground level] during the day and 1,000 ft AGL at night, the low-altitude index [on the radio altimeter] is to be set to one or [the] other of these values during the cruise flight phase.”
The helicopter had accumulated 1,857 hours since entering service in 2007. It was equipped for day or night flight under visual flight rules. The helicopter had been flown 245 hours since its last 600-hour inspection in February 2010 and one hour since a 100-hour inspection in August 2010.
The Turbomeca Arriel 2B1 engine had accumulated 245 hours (and 301 cycles) since its installation in March 2010 and had recorded 735 hours total time.
The only weight-and-balance documents were kept in the helicopter and could not be recovered after the accident. The pilot of the other helicopter said that the loads carried by both aircraft were similar and that his helicopter’s weight-and-balance documents showed that it was within the manufacturer’s limits.
The accident helicopter was equipped with a radio altimeter, but investigators were unable to determine what alert height had been selected by the pilot before the accident. The pilot of the first helicopter said that, as the clouds lowered, he had set his radio altimeter index to 30 ft.
Low Clouds, Low Visibility
According to weather observations from Météo France personnel and Dumont d’Urville equipment, visibility early on the day of the accident was about 40 km (25 mi), but by late afternoon, high clouds developed. In the evening, weather conditions deteriorated, with visibility falling to 8 km (5 mi) and then to 3 km (2 mi), lowering clouds and strong winds; ultimately, a storm reduced visibility to 40 m (131 ft).
A Météo France satellite map about seven hours before the accident indicated that there was “very low cloud” — which can include stratus and fog banks — between the ship and the Dumont d’Urville base.
As the pilots prepared for the flight, however, neither they nor anyone at the Dumont d’Urville base had access to the satellite images or data describing weather conditions between the ship and the base. The pilots knew only that an Oct. 27 forecast had called for “a little cloud, with the sky clouding over in the afternoon” on the 28th and “unsettled weather” on Oct. 29, and that a 1530 observation at Dumont d’Urville had noted visibility of 40 km, with the sky “covering slowly” and “confirmation of an expected deterioration,” the accident report said.
The pilot of the first helicopter, who had flown the previous year for the company that held the IPEV contract, said that actual weather conditions after departure were good and that the forecasts were accurate for about the first 150 nm (278 km) of his flight.
Then, “53 nm [98 km] from Dumont d’Urville, he encountered difficult conditions associated with a cloud ceiling of about 200 ft and visibility of 1,500 m [slightly less than 1 mi] for about 15 nm [28 km],” the report said, describing the conditions as “whiteout-type.”
The pilot said that he did not consider landing on the pack ice, which would have been too weak to be safe, and that, although fuel reserves would have been sufficient for him to reverse course, he did not turn back because he was “not sure that he could locate the ship again quickly,” the report said.
After about 15 nm, weather conditions improved, and the weather was good for the remainder of his flight. He said that he suggested to the accident pilot that he keep the helicopter at 3,000 ft to remain above the low clouds, but the accident pilot said he preferred to fly beneath the cloud layer.
At 1925, when he left the base to search for the second helicopter, he found “very poor” weather conditions which “forced him to turn back when approximately 18 nm [33 km] from the accident site,” the report said.
Adélie Land has no radio-navigation aids, so pilots use the global positioning system (GPS). A GPS unit was installed in the accident helicopter, and the pilot also carried a portable unit.
Pilots of the two SAF helicopters communicated throughout their flights using aircraft very high frequency (VHF) radios; the pilot of the first helicopter said, however, that transmission quality was poor for the last 30 nm (56 km) of his flight. The radio transmissions were not recorded.
The accident helicopter was not equipped with flight recorders, which were not required by regulations. Investigators were unable to recover the memory card from the helicopter’s data tracking system from the crash scene; instead, they used flight-following data that had been transmitted by satellite to the operator to determine the helicopter’s flight path.
While on the ship, the pilot had taken medication to fight seasickness, according to one witness and a laboratory analysis of the pilot’s blood samples. One side effect is the drug’s “significant sedative effect,” the report said, noting that the packaging includes a warning that, because the medication can cause drowsiness, users should “be very careful” about driving or using other heavy machinery.
“Certain side effects, notably the sedative effect, reduce a pilot’s ability to adapt to flying conditions when there are few visual references,” the report added.
The report said it was unclear if the pilot had taken the medication on the day of the accident, and the lab analysis could not determine how much of the medication was in the pilot’s bloodstream during the flight.
A February 2010 audit of SAF by the Direction de la Sécurité de l’Aviation Civile (DSAC) “identified several deficiencies” in the quality assurance system and flight safety that “constituted a major deviation,” the report said, noting that the DSAC also found that the operator had not responded to previous agency requests for action on minor deviations, including deviations associated with the operations manual, initial training and practice sessions for the flight crew and operation of the accident prevention and flight safety program.
Some items were discussed orally with no written record of the comments, the report said.
The DSAC was informed of SAF’s activities in Adélie Land only after the accident, and as a result, the agency suspended the passenger transport flights, “pending the necessary amendments by the operator to its operations manual,” the report said. The manual was amended in December 2010, prompting the DSAC to rescind its suspension and renew the company’s aircraft operator certificate.
The report noted several reasons for the pilots’ “powerful incentive to undertake the flight” — including the damage to the ship and the need for repairs, the poor weather forecast for the following day and the “expectations of the over-wintered personnel on the Dumont d’Urville base.”
If the pilots had known about the area of clouds visible on the satellite map, they could have planned for the weather or canceled their flight, the report said.
Instead, they took off from the ship, and as weather conditions deteriorated, the accident pilot “changed direction several times, on one occasion in order to fly under the cloud layer,” the report said. “These actions may have been motivated by his fear of not being able to land at his destination or by it being impossible to fly above the cloud layer. … His frequent changes of direction appear to be indicative of his search for visual reference points or better meteorological conditions.”
The report said that the pilot might have been reluctant to turn back to the ship because of “his concerns regarding landing on a helideck at sea.”
The report added, “In addition, the fact that the first pilot had managed to negotiate the area of bad weather by flying at low altitude was a strong but effective incentive to continue with the flight.”
His search for visual references may have delayed his responses to radio messages from the other pilot, the report said, adding that, because there was no indication of a technical problem, “it is likely that … the pilot had to fly in whiteout conditions and as a result was disorientated by losing all his visual references. … Since the pilot was flying at a very low altitude, the helicopter probably hit the pack ice during a descent that the pilot failed to notice due to his preoccupation with searching for visual reference points.”
The report said that the operations manual did not prescribe objective criteria to help pilots decide whether to accept Adélie Land flights, and that SAF had not told DSAC about the new base in Adélie Land or requested an exemption from the agency to permit flights from a helideck at sea.
“The relationship between the authority and the operator was not sufficient to ensure that SAF Helicopteres operated flights safely,” the report said.
This article is based on the English translation of the BEA report, “Accident on 28 October 2010 off Adélie Land (Antarctica) to the AS 350 B3 Squirrel, Registered F-GJFJ, Operated by SAF Helicopteres.” September 2012.