Operators look to default use of cockpit automation in over-water helo operations
Helicopter operator CHC Scotia is encouraging greater use of automation in its flights in the wake of the Aug. 23 crash of a Super Puma as it approached a Shetland Islands airport.
CHC is urging crews to “default” to the use of onboard automated systems after U.K. air-accident investigators reported a loss of airspeed during the approach of aAS332L2 Super Puma, G-WNSB, was “unobserved” by the pilot and co-pilot moments before it crashed into the North Sea.
Four oil workers died when the Super Puma ditched while on approach to Sumburgh Airport after a flight from the Borgsten Dolphin drilling platform on behalf of oil company Total.
Eurocopter's analysis of the aircraft's flight data recorder found that the aircraft's nose-high attitude, low airspeed, high rate of descent and high power levels had placed the AS332L2 into vortex-ring conditions. Using that data, modeling demonstrated that with reduced helicopter performance and limited height available, the “impact with the sea was unavoidable,” said the U.K. Air Accidents Investigation Branch (AAIB) in a special bulletin published on Oct. 18.
Such a recommendation to favor automation, however, appears to fly in the face of recent accidents such as the crashes of an-200 in San Francisco, or an over the Atlantic Ocean, where it has been suggested that pilots had become overreliant on automation in the cockpit. CHC's thinking is in line with that of helicopter manufacturers, who are advocating the increased use of automation into the cockpit.
Eurocopter points to operations of its EC225, which, despite its recent grounding due to the bevel-gear vertical-shaft issues that forced two aircraft to ditch into the North Sea in 2012, now include wide use of automation with a TCAS II (traffic-alert and collision-avoidance system) linked to the aircraft's autopilot.
also has been working to enhance automation in the cockpit, having earlier this year introduced an application into the avionics of the S-92 to reduce the workload of pilots approaching oil platforms. The system has been under development since 1997 but was only approved by the last May. While the rig-approach app flies the route automatically, the crew can spend more time looking outside for visual clues, particularly during bad weather.
The subject of automation will also be studied in a joint safety review announced by CHC and the other two major North Sea operators: Avinicis, the parent of Bond Offshore Helicopters; and Bristow Group.
The helicopter in the Aug. 23 crash had been flying an approach into Sumburgh's Runway 09. The aircraft's commander had prepared for a non-precision approach with the co-pilot monitoring the vertical-descent profile, referencing the airport approach chart. Visibility was 4,000 meters (2.1 nm) but in haze with an 18-kt. surface wind.
At 2.3 nm from the airport, the Super Puma's airspeed fell below 80 kt. and “continued to reduce, unobserved by the crew,” says the AAIB report.
The aircraft was also below the altitude expected along the approach. The report states that the cockpit issued two “check height” automated warnings to the crew. The second warning was followed by a “100 feet” automated call, 2 sec. before the aircraft hit the water. “At some point the commander saw the sea, but he was unable to arrest the helicopter's descent and it struck the surface shortly thereafter, at 1717 hr.,” investigators note.
The report says CHC's standard procedures state that the pilot not flying is required to monitor the approach and look outside to acquire visual references for landing, while the other pilot flies the approach on instruments. If a visual reference is not acquired, then a missed-approach profile should be flown.
Moments before the Super Puma ditched, the co-pilot realized the helicopter was about to enter the water and activated the flotation system. Once in the water, the helicopter rapidly inverted, but remained afloat, for 14 of the 18 passengers to escape along with the pilot and co-pilot.
The AAIB says the survivability aspects of the crash are subject to ongoing inquiries, but that investigators have recommended the airport owner, Highlands & Islands Airports Ltd., provide a water rescue capability that can be used in all tidal conditions.
The accident, the fifth in four years in the North Sea, sparked an outcry over safety, including a Facebook page—”Destroy the Super Pumas”—although much of this furor has died down since the AAIB report stated the cause was not a technical issue with the aircraft.
Nonetheless, the accident has prompted a total of at least five inquiries and reviews from the Oil and Gas U.K. trade association, U.K. and Norwegian aviation regulators, the U.K. government's transport committee, the Helicopter Safety Steering Group—an offshore safety committee—as well as the North Sea operators.