The Royal Canadian Air Force grounded most of its Maritime CH-148 Cyclone fleet after discovering tail cracks caused by localized stresses from electronic support measures and satellite communications antenna mounts
Most of the Royal Canadian Air Force’s Maritime fleet of CH-148 Cyclone helicopters underwent repairs after cracks were discovered in the tails of the aircraft in late 2021.
Cracks were initially found on one of the Sikorsky-made helicopters during routine maintenance on Nov. 26, 2021. After discovering cracks in three additional CH-148s, the RCAF conducted a comprehensive fleet inspection that revealed 19 out of the 23 CH-148 aircraft had cracking problems. Two were found to have no cracking and the remaining two were in long-term maintenance and had not yet been inspected at the time.
“12 Wing Shearwater, which encompasses the entire fleet, is prioritizing the order of repair to maximize return to serviceability for each aircraft,” according to a Department of National Defense statement to CBC News on Dec. 4, 2021.
While 17 of the aircraft were based in Nova Scotia and six in Pat Bay, B.C., to support the Royal Canadian Navy’s Pacific fleet, the entire fleet was encompassed within 12 Wing Shearwater. For “reasons of operational security,” the department declined to say how recently two unaffected aircraft entered service or where they were located.
Root Cause Identified
The Royal Canadian Air Force determined that the cracks appeared in the tail booms due to local stresses caused by the equipment installed there, Alert 5 first noted. In a statement on Jan. 31, 2022, Canada’s Department of National Defence said its technicians and Cyclone manufacturer, Sikorsky Aircraft, made an “initial determination” that equipment on the tail sections of the aircraft was too heavy to be supported in flight, thereby causing the cracking, CBC News reported.
Sikorsky spokesperson John Dorrian explained that the cracks “are the result of local stresses caused by the electronic support measures and [satellite/communications] antenna mounts, which were not previously anticipated.”
According to Dorrian, the S-92 had not experienced the same cracking issues because it did not have the same electronic support measures and antenna mounts as the Cyclone.
Repair Efforts and Long-Term Solutions
The fleet was grounded while plans were made on how to proceed with repairs. Sikorsky worked with the RCAF to make repairs, with experts belonging to the service estimating that repairs to some of the aircraft would be completed in “the next few days.”
Repairs on the Cyclones were ongoing at 12 Wing Shearwater near Dartmouth, NS, with each aircraft’s cracking requiring a “unique solution,” said the Defense Department. As of Jan. 28, 2022, 11 of the Cyclones had been repaired, with an additional four undergoing repairs.
The department also stated that the repairs were not permanent fixes. The military worked with Sikorsky to establish a “final determination” of the cause of the cracks by the end of February 2022 before creating a permanent solution to the issue.
“The long-term solution will take into account these load paths, mitigate the local stress at these interfaces, and eliminate the cause of the cracking,” Dorrian said in an email.
Operational Impact
The issue with the Cyclones had some impact on flood-relief operations in B.C., where helicopters from 443 Squadron, operating from their base at Patricia Bay, were supposed to provide support. Other air assets were able to fill the gap instead.
The Defense Department stated that the Air Force had a “robust flight safety culture,” and it was not uncommon for issues to be found early in the life cycle of new aircraft, such as the Cyclones.
“There is no immediate safety hazard, and we have complete confidence in the immediate solution being implemented,” the department said. “The fleet continues to be operational and will be monitored and tested on a regular basis in accordance with our airworthiness program.”
About the CH-148 Cyclone
Sikorsky and Canada’s Department of National Defence led a team that designed, built, and configured the CH-148 Cyclone for anti-submarine warfare (ASW), anti-surface warfare (ASuW), maritime search and rescue (SAR), overland operations, and utility missions.
Based on the Sikorsky S-92, as Canada’s first true intelligence, surveillance, and reconnaissance (ISR) helicopter, the fly-by-wire Cyclone was equipped with a fully integrated mission system, modern sensors, and a multi-mission cabin — providing a quantum leap in maritime helicopter capability.
Entry into service with the Royal Canadian Air Force occurred in mid-2018 aboard one of the Royal Canadian Navy’s Halifax-class frigates. The full operational capability of the fleet was scheduled for 2022.
In 2020, six members of the Canadian military were killed when a Cyclone crashed in the waters off Greece because of a glitch with the autopilot function.
Photo by Dennis Jarvis from Halifax, Canada via Wikipedia
