The Eurocopter EC225 medium twin now has a traffic collision avoidance system (Tcas) II integrated into its autopilot, eliminating the need for pilot input in emergency avoidance maneuvers. The first such standard-equipped EC225 was delivered earlier this year. Offshore operator Bristow previously STC’d a Tcas II installation on the AS332 Super Puma; Eurocopter claims to go one step further, with more integration.
Rockwell Collins supplied the Tcas II itself and Eurocopter developed the integration in-house. The system was EASA-certified under a special condition, according to Eurocopter test pilot Hervé Jammayrac. “CS-29 rules have nothing about helicopter Tcas II,” he said.
In case of conflicting trajectories and a traffic alert, the Tcas II may have to issue a resolution advisory (RA). The autopilot will react to an RA immediately, without waiting five seconds for the pilot to take evasive action. The autopilot will command a climb or descent to ensure safe separation from other aircraft, and then return the aircraft to its original attitude, altitude and heading.
The system performs better than a non-automated Tcas II, according to Eurocopter. Because RAs are rare, pilots have limited experience dealing with them, Jammayrac explained, and consequently they sometimes overreact and climb too steeply, triggering a second RA.
The automated system keeps the pilot in the loop. “The crew should not be surprised, thanks to indications on the main displays, including the vertical-speed scale, and the RA comes after an aural traffic alert,” Jammayrac said. Finally, he emphasized that helicopter autopilots are always “transparent,” in that the pilot can overrule the autopilot with normal control inputs. He can also disengage the Tcas mode of the autopilot.
The system will probably not be adapted to lighter aircraft. While it looks useful for scheduled offshore operations, it would be less suited to operations such as EMS or aerial work. “Below 1,000 feet, Tcas II does not provide RAs, only positions and traffic alerts,” Jammayrac pointed out.
According to Jammayrac, the only other aircraft to have Tcas II integrated into the autopilot is the Airbus A380. Next in line at Eurocopter for this automation is the in-development EC175 medium twin.