VICTORIA -- The Canadian military's fleet of Cyclone helicopters will return to the skies "in the coming days," officials announced Tuesday, less than two months since a crash off the coast of Greece killed six service members.
The announcement came as the military revealed new details about what led to the crash of the helicopter known as Stalker 22 while attempting to land aboard the Halifax-class frigate HMCS Fredericton in the Ionian Sea.
Analyzing data recovered from the aircraft wreckage, National Defence officials say a conflict arose between the helicopter's autopilot software and the flight crew's maneuvers in the moments before the crash.
Pilot inputs were "overtaken by other data," said Lt.-Gen. Alain Pelletier, commander of the 1st Canadian Air Division. "In that term, the pitch channel was no longer responding to the pilot."
The helicopter was passing along the port side of the Fredericton from stern to bow at low altitude when the aircraft "did not respond as the crew would have anticipated," said Col. John Alexander, National Defence's Director of Flight Safety and Airworthiness Investigative Authority.
Investigators say they were able to recreate the doomed flight's maneuvers using a simulator and found the aircraft responded "almost identically," Alexander said.
"The accident was unavoidable based on their low altitude and consequently the lack of time that they had to realize that the aircraft was not responding to their inputs," he added.
The entire Cyclone fleet was put on an "operational pause" immediately after the crash as a precaution. That pause was lifted Tuesday, though officials said it may take several days before the Cyclones return to the skies.
"I assure you this decision was not taken lightly," Pelletier said of the aircraft's return to operations.
The investigation continues into what the military described as "aircraft systems and human factors" that led to the crash.
The remains of Sub-Lt. Abbigail Cowbrough and partial remains of Capt. Brenden Ian MacDonald were recovered shortly after the helicopter went down during a NATO training mission on April 29.
The remains of the four other Canadian Armed Forces members on board – Capt. Kevin Hagen, Capt. Maxime Miron-Morin, Sub-Lt. Matthew Pyke, and Master Cpl. Matthew Cousins – have not been identified.
Officials said Tuesday they have "full confidence" in the Sikorsky-made aircraft and said new flight procedure training will address the autopilot bias issue.
The crash of Stalker 22 was the third publicly known incident involving a Cyclone helicopter since the military accepted delivery of the aircraft in 2015.
A software problem in the flight control system of one Cyclone in March 2017 caused the helicopter to suddenly drop during a test flight. Another had a “hard landing” on board a navy support ship while deployed in the Pacific in February 2019.
"The information we have received from the investigation so far indicates that the accident that happened on the 29th of April is absolutely unrelated to any previous issues that you would have heard concerning the Cyclone," said Brig.-Gen. Nancy Tremblay, Director-General of Aerospace Equipment Program Management and Technical Airworthiness Authority.
The resumption of flights for the Cyclones, which are based in Patricia Bay, B.C. and Shearwater, N.S., will be accompanied by updates to flight manuals so pilots know about the software override problem and how to respond if it arises, as well as restrictions on certain flight activities, officials said.
