Helicopter operators continue to voice concern about sharing airspace with remotely piloted aircraft systems (aka RPAS/UAS/drones), highlighting the danger of a midair and stressing the need for better regulation of and more research into RPAS operations.
Drones present a particular danger to helicopters because they occupy the same lower airspace, Thomas Rüder, an expert with the European Cockpit Association (ECA), said at the EASA’s rotorcraft symposium in December. Annually in Germany, manned aircraft make an estimated one million flights below 500 feet.
Spotting drones in time is hard for helicopter operators: the ECA asserts that a small drone, visible only at 65 feet out, is just 0.3 seconds away from a helicopter flying at 130 knots.
Just as the drone is difficult for the helicopter crew to see, modern helicopters–with their low noise signatures–can be hard for the drone operator to hear, possibly preventing the operator from perceiving the manned aircraft until it is too late for collision avoidance, Rüder noted. In terms of kinetic energy, a microdrone weighing 170 g (less than half a pound) can collide with a helicopter with more than 585 J, for a punch harder than that of a 9mm bullet.
Drones already affect operations, Rüder said, citing conflicts that have forced firefighters to ground aircraft. In the Netherlands, RPAS flights in the vicinity of the airport delayed the takeoff clearance of anEMS helicopter by three minutes, according to a study by Dutch aerospace research center NLR.
The ECA is calling for research on collision avoidance systems. Geo-fencing, static and dynamic, might be a solution, Rüder suggested. As for regulation, he believes “the responsibility to see and avoid manned aircraft must be placed solely on the RPAS pilot.”
The NLR made a number of recommendations, among them instilling in RPAS operators a culture of airmanship and safety and organizing meetings for each side to educate the other about its operations. Incident reporting should be improved and the consequences of an RPAS strike–such as a battery fire–must be studied, the NLR said.