The CH-148 Cyclone helicopter has what the Air Force calls a “triple redundant” flight control system – and during a training mission in 2017 off Nova Scotia, these three computers have momentarily broken down.
It was a major software problem, alarming enough to ground the fleet for nine weeks.
At the time, the military described the incident publicly as a “serious bump” that reset the controls and caused the aircraft to lose altitude briefly and suddenly. The pilot successfully recovered and landed safely.
A defense expert now says that this incident could turn out to be of vital importance while investigators are investigating the cause of last month’s cyclone accident in the Ionian Sea. The accident, which occurred while the helicopter was participating in NATO operations, claimed the lives of six Canadian soldiers – four crew members and two sailors.
Chopper “flew into the ocean,” sources say.
Multiple defense sources tell CBC News that at the time of the crash, the cyclone was performing a low-speed and high-speed photographic pass of HMCS Fredericton, a maneuver known to the Air Force as “Brownie Run” after a NATO camera. .
Without warning, the helicopter suddenly pitched forward and “flew into the ocean,” said the sources, who received anonymity due to the sensitivity of the investigation.
The incident of March 9, 2017 involving a software problem on board a cyclone is a public subject. What wasn’t fully revealed at the time, the sources say, is that the three interconnected computers all inexplicably reset – which could have led to a catastrophic crash.
When the fleet grounding ended three years ago, the Cyclones continued to operate for a period of time under a series of flight restrictions while their manufacturer, Sikorsky Aircraft, resolved the software problem with a pre-planned upgrade.
These and other restrictions prevented the aircraft from operating near the ground, sloping landings, and lifting equipment and personnel.
The limitations were designed to correct the aircraft’s pitch and roll and were only applied at certain altitudes and in specific flight control modes.
“This is more of a technical restriction and avoiding parts of the code, really, in the software, making sure we don’t induce fault,” said Colonel Peter Allan, commander of the 12 Wing Shearwater, Nova Scotia. . (It was cited in the aeronautical publication Global Flight.)
“Sikorsky clarified very precisely which code elements are affected in the software and how we could trigger these code elements.”
A tight schedule
Cyclone software has been upgraded on at least 14 of 28 cyclones ordered by the Air Force, including one that crashed off the coast of Greece in late April. Work on the aircraft was on a tight schedule because the Air Force had begun to withdraw the CH-124 Sea King maritime helicopters after more than five decades of service.
The Department of National Defense (DND) was recently asked if restricted flight certificates were still outstanding or if the Cyclones had restrictions on their operations.
“There were no additional restrictions added to the fleet after the crash, as the investigation is still underway,” said Dan LeBouthillier, media relations manager, in an email.
“However, as with all other aircraft in the RCAF inventory, the CH-148 Cyclone is subject to the technical limits imposed by the original aircraft manufacturer as well as to the operational limits imposed by the CRA.”
LeBouthillier listed some of these technical limitations – which cover things like the inappropriateness of operating the aircraft in climates where the temperature exceeds 47 degrees Celsius, and the proper way to bend its rotors.
An “operational break”
DND also declined to say whether the aircraft was observed pitching forward and accelerating in the ocean.
“Since any such information is part of the flight safety investigation, we will not discuss it publicly to ensure the integrity of our investigative efforts,” said LeBouthillier.
An “operational break” was imposed on the entire Cyclone fleet after the crash; essentially, the fleet is again immobilized while investigators analyze data from the aircraft’s twin flight recorders. Defense Minister Harjit Sajjan said last week that the investigation could take a year or more.
Defense Policy Analyst Michael Byers, University of British Columbia, who has written reports and articles criticizing the maritime helicopter program, said the software failure could be significant if investigators ended up excluding pilot error.
“No time to answer”
Because the plane was flying near the ocean surface, he said, he would have been in a vulnerable position and the two pilots would have had very little time to react.
“If you are only a few hundred meters above the water, you have no time to respond,” he said.
Investigators will also have to ask themselves if there are other undetected flaws in the Cyclone’s fly-by-wire (FBW) software, said Byers.
“We don’t know exactly what happened, but [information to date] suggests a change in the flight control system … something went wrong, either a computer problem or maybe a pilot error, but that seems unlikely, “he said.
The federal government and DND have an obligation to be more transparent about the accident and the investigation, he added.
DND delays in disclosing the facts
The first reports of the accident came from local media and from Greece. It was NATO – not the Canadian government – that initially confirmed that the plane had broken down.
In subsequent public statements, DND downplayed the idea that the helicopter crashed near HMCS Fredericton – and the fact that it happened in front of witnesses was completely ignored for almost a week after the ‘accident.
“It’s about the safety of flight crews,” said Byers. “I don’t see how the Canadian government could withhold information.”
Recently, the federal government was still trying to figure out how to recover the wreckage and the remains of the missing crew members in water about 3,000 meters deep.
The body of the second lieutenant. Abbigail Cowbrough was found the day of the accident. Partial remains belonging to Captain Brenden Ian MacDonald were also found.
The remains of Captain Kevin Hagen, Captain Cpl. Matthew Cousins, second lieutenant. Matthew Pyke and Captain Maxime Miron-Morin.
The National Post reported on Tuesday that the federal government is in talks with the United States over the use of some of its deep diving technology to recover the plane.
CBC News asked DND Monday for the status of the rescue operation. In a statement released Tuesday evening, the ministry said no decision had been made.