Accident NOT Attributed to Continental Engine AD

On Friday 24 February 2023, approximately four-minutes after departing Duluth International Airport (DLH), a six-year-old Cirrus SR22 GTS G6 (N929DR) went down into the frozen St. Louis River near Bong Bridge. The aircraft broke through the ice and partially submerged. The airplane’s pilot and sole occupant, Dave Rathbun (52), lost his life.

At the time of its last radar contact, N929DR’s had attained an altitude of 1,125-feet-MSL and a ground-speed of approximately 130-knots.

To the subject of the downed Cirrus, St. Louis County Sheriff’s Deputy Sergeant Ben Nye stated: “We had a report just after four-o-clock came into 911 about a single airplane crash near Grassy Point drawbridge.”

The St. Louis County Rescue Squad was tasked with the difficult work of removing the aircraft’s wreckage from the ice. Several first-responders were reportedly friends of Mr. Rathbun’s.

Cirrus, in a post-accident statement, confirmed the victim was in fact Dave Rathbun, a highly-regarded aerospace engineer and 26-year Cirrus employee who’d played key roles in the early design and certification of Cirrus’s SR20, SR22, and SR22T aircraft and served as chief project engineer throughout the development and entry into service of the company’s SF50 Vision Jet. Out of respect for the deceased, Cirrus offered neither comment nor speculation pertaining to the accident’s cause.

The downed SR22’s registration number falls outside the range of those Cirrus aircraft impacted by a recent grounding attributed to possible improper installation of counterweight retaining rings within the engine crankshaft counterweight grooves of the planes’ Continental Aerospace Technologies, Inc. (Continental) reciprocating engines.

Concerns over subject engines’ airworthiness compelled Cirrus to ground the SR22 and SR22T fleets in February 2023.

In the grounding’s wake, Continental issued a Service Bulletin directing Cirrus owners to have their aircraft checked for proper installation of the aforementioned counterweight retaining rings. The FAA, too, was prompted to action, issuing an Airworthiness Directive (AD) applicable to “certain Continental Aerospace Technologies, Inc. reciprocating engines.”

In a letter to SR22 and SR22T models affected by the grounding, Cirrus wrote: “Cirrus Aircraft has been informed by Continental…of an issue that affects engines that power both Cirrus Aircraft’s SR22 and SR22T models … While we are still working with Continental to determine the scope of the issue and the specific serial number range of affected aircraft, we are pro-actively making the decision—out of an abundance of caution—to pause all internal Cirrus Aircraft company flight operations on SR22 and SR22Ts manufactured and issued a Certificate of Airworthiness from June 1, 2021, through February 7, 2023.”

No correlation has yet been established between the accident aircraft and the fleet grounding, the Service Bulletin, and the Airworthiness Directive.

The accident’s cause remains unknown and the National Transportation Safety Board’s (NTSB) investigation is ongoing.

FMI: www.ntsb.gov