Cyclone returns to service for first time since deadly crash

The air force has conducted its first flight of a CH-148 Cyclone since last spring's deadly crash — and the Department of National Defence is signalling it is ready to resume delivery of the remaining maritime helicopters still on order.

A Cyclone belonging to 423 Squadron, based in Shearwater, N.S., conducted a training flight near Halifax Harbour on Monday — almost one week after the military cleared the aircraft to resume operations.

Aircrew are being given refreshed training on avoiding the flight control software problem that brought down a Cyclone off the coast of Greece on April 29, an accident that killed six members of the military.

Jessica Lamirande, a spokeswoman for the Department of National Defence (DND), said CH-148 deliveries will resume shortly after the new flight procedures are formally approved and all aircrew have received their additional training.

Out of the air force's original order of 28 helicopters, roughly eight aircraft have not yet been delivered. Throughout the delivery process, the military has been sending some of its already delivered helicopters back to the manufacturer, the Sikorsky Aircraft Corporation, for software upgrades.

The final aircraft with the final software configuration is due to be delivered by the end of 2021, according to Lockheed Martin, which now owns Sikorsky.

The investigation into the crash is still ongoing, but flight safety investigators and the senior commander in charge of joint flying operations said last week a combination of a software "bias" and the crew's inability to react to the unexpected moves of the flight control computer likely contributed to the tragedy on April 29.

The lead investigator, Col. John Alexander, said the crash and the software issue were "completely unforeseen."

Sikorsky was asked to review the flight control system for other potential problems and DND said Tuesday that the company has investigated and confirmed that all flight director control biases are "known and understood."

Lamirande also insisted that — despite the accident, the flight restrictions and the questions around software — the Cyclone continues to meet the air force's performance requirements.

"The CH148 Electronic Flight Control System (EFCS) provides the functionality required" by the maritime helicopter specifications, Lamirande said in an email to CBC News.

The "revised operating procedures and improved training will ensure that aircrew avoid" the kind of flight conditions that caused the crash and will teach them to "recover from unexpected helicopter behaviour that may be associated with flight director control bias," she said.

A defence expert and long-time critic of the Cyclone program said he was astounded by that statement.

"They're asking pilots to fly around the defect and not to trigger it," said Michael Byers, a professor at the University of British Columbia who has tracked the Cyclone project.

"The defect that brought the aircraft down in the Ionian Sea caused fatalities and now pilots must try to avoid the fault. It's unacceptable."

He also questioned the claim that Sikrosky has caught all of the software "biases," arguing the company didn't know about the fatal problem until after the crash.

"I don't have much confidence they have thought of everything," he said, noting the Cyclone is a combat aircraft and may be pushed beyond its limits in its capacity as a submarine-hunting helicopter.

Byers said he questions whether the Cyclones should be allowed back in the air so soon — or at all.