Airbus Helicopters is integrating sensors to enable hands-off platform approaches
For offshore helicopter pilots, the approach to oil and gas platforms is one of the most work-intensive periods of the flight.
During bad weather, pilots can struggle with high winds, while low visibility and clouds sometimes obscure heli-decks that often sit hundreds of feet above the sea level, and obstacles such as cranes and gas flares create challenges in the final moments before touchdown.
But, formerly Eurocopter, is working to reduce that workload—at least during the approach phase—down to just a single button push, allowing pilots to keep their heads up during this critical phase of flight. The company is working on its Rig N'Fly approach system, destined for installation in a new version of its EC225 heavy helicopter, called EC225e (“e” for “enhanced”), which is due to fly for the first time in 2015.
's system, undergoing flight testing in the south of France, differs from 's approach system by integrating feeds from other sensors on the helicopter. Like the Sikorsky system, it uses GPS points to provide it with an approach fix to the platforms. Key to its introduction is the use of Navtech's regularly updated oil and gas platform data that can be fed into the EC225e's new EuroNav 7 situational awareness system. Rig N'Fly also receives data from the traffic collision-avoidance system (TCAS II) integrated into the helo's autopilot and the Automatic Identification System (AIS), which will be standard to the EC225e.
“The principle is that all the systems are working together in an integrated way during the final approach,” says Rupert Hibbert, a senior manager working on the marketing of the Rig N'Fly Approach system, who demonstrated the system to Aviation Week at Heli-Expo 2014 in Anaheim, Calif., last month.
With rig data already in the flight management system (FMS), as the crew enter the turning point, they push the “Alt A” button on the autopilot controls, activating the system. At 3,000 ft., the system activates the AIS system used to track surface ships, which notes their heading and speed as well as ships in the area near the platform and checks whether any ships are likely to be close or converge with the helicopter's flight path.
“There is often a lot of shipping around any platform, and sometimes these vessels are carrying other oil platforms, some of which are a significant height above the water,” Hibbert says. “The AIS provides awareness and early warning ahead of the final approach, giving the crew the option to go into the hold until the vessel has passed or to fly around the obstacle.”
The helicopter will then descend toward 1,500 ft. and the initial approach fix (IAF), and the autopilot will use its flight envelope and power protection to maintain course and height, ready for a single-engine failure at any time during the approach. At the IAF, the system activates the TCAS II, which is able to make avoidance maneuvers should it detect any conflicts.
During the period between the IAF, the final approach fix (FAF) and the minimum descent altitude, the helicopter can be flown entirely hands-off and the speed is not limited. “Pilots can enter the FAF at 120 knots, if they wish,” says Hibbert.
As the helicopter reaches the missed approach point, the crew then have the option of flying a missed approach using the “takeoff, go-around” button and starting again or “flying the disk” down onto the heli-deck of the platform. Airbus is looking at introducing a control mode that puts the helicopter into a straight and level hover that would enable the pilot to slew the helicopter horizontally above the pad and reduce power, bringing the helo safely onto the deck.
Part of Airbus's work to develop the system was prompted by the February 2009 incident involving an EC225 operated by Bond Offshore. As the crew approached a North Sea platform during a night-time operation, poor visibility hindered their view of the platform, while visual illusions degraded the crew's visual cues. Meanwhile, the helicopter's audio height warnings did not activate because, according to accident investigators, the helicopter's Terrain Awareness Warning System (TAWS) had malfunctioned and the crew had suspended the warnings. While all 16 passengers and two crew managed to escape the helo safely, the EC225 was damaged beyond repair.
To prevent controlled flight into terrain incidents such as this during approach, Rig N'Fly will use power and envelope protections to stop the aircraft from dipping below 150 ft.
Fifteen EC225e models were ordered by the helicopter arm of Dublin-based Lease Corporation International during Heli-Expo 2014.