Feb. 26—DULUTH — Cirrus Aircraft has a difficult situation on its hands, following the Federal Aviation Administration's decision Thursday to issue an airworthiness directive that effectively grounds many of the company's recently produced piston-engine airplanes until they can be inspected.
At issue is a manufacturing error discovered by Continental Aerospace Technologies, Cirrus' supplier of engines for its two most popular plane models, the SR22 and the turbocharged SR22T.
Crankshafts in some of Continental's engines produced between June 2021 and February 2023 were improperly assembled, making them susceptible to catastrophic failure.
The Cirrus SR22
involved in last week's fatal crash
in the St. Louis River had an airworthiness date of 2016 and was registered in 2020, according to data from flight-tracking website FlightAware.
After learning of the problem from Continental, Cirrus notified customers Feb. 8 that it had decided to ground SR22s and SR22Ts in its own company fleet "out of an abundance of caution" until they could be inspected and verified as safe for flight.
The FAA directive published this past week in the Federal Register makes it illegal to fly any plane with one of the suspect engines until it can be inspected and repaired, if necessary. The FAA document explained that "because of the urgency of the unsafe condition, this AD requires inspection of any affected crankshaft assembly before further flight."
The sole exception is for airplanes that must be relocated by means of a single flight to access the nearest qualified service center.
The types of engines in question come standard equipped in both the SR22 and SR22T. In all, Cirrus shipped at least 663 airplanes of those makes within the time frame identified as a period of concern, according to stats from the General Aviation Manufacturers Association. Those numbers do not include any aircraft delivered in 2023, as GAMA's shipment report is issued on a quarterly basis.
Cirrus reported that it believes roughly 690 aircraft will be affected but not every airplane shipped within the identified time frame. A list of specific engine serial numbers requiring inspection has been issued as part of the order.
The federal directive provides details as to how the issue came to regulators' attention, stating: "The FAA received a report of a quality escape involving improper installation and inspection of counterweight retaining rings in the engine crankshaft counterweight groove during manufacture. The FAA has also received reports of two ground engine seizures and one in-flight loss of engine oil pressure due to improper installation of the counterweight retaining rings during manufacture."
The stakes of a resulting failure can be high, according to the directive, which went on to say: "The counterweight retaining rings are part of the engine crankshaft counterweight assembly retention system. Loosening of a counterweight retaining ring may result in the loss of retention of the counterweight. This condition, if not addressed, could result in loss of engine oil pressure, catastrophic engine damage, and possible engine seizure. The FAA is issuing this AD to address the unsafe condition on these products."
The FAA said a total of 2,176 crankshaft assemblies require inspection.
Regulators estimate that of all those crankshaft assemblies, 1,632 are already installed in U.S. aircraft.
Inspecting the crankshaft assemblies of uninstalled engines and correcting them, as needed, is a relatively simple matter. But that becomes a more costly and labor-intensive proposition when it comes to engines that are already in service.
The FAA estimates that roughly 33% of the airplanes affected by its directive will need to have one cylinder removed, another third of the planes will require the removal of two cylinders, and the remainder must have three cylinders removed to be cleared for flight once again.
The estimated cost to inspect and/or repair each grounded airplane is expected to range from about $1,000 to $2,000, according to FAA estimates.
Many of the impacted aircraft likely remain under warranty, meaning their owners may not be responsible for the cost. Cirrus said most of its affected aircraft are still covered by warranty.
In response to a News Tribune question about the ability to resolve the issue quickly, Cirrus issued a statement saying: "We have a global service network of over 200 authorized service partners that are capable of performing the required inspection. Owners of affected engines are working now to arrange service at these centers."
Earlier this month, Continental had acknowledged concerns about certain engines it had produced and recommended airplanes equipped with them be immediately inspected, but that warning excluded aircraft with engines that had been in service for more than 200 hours.
Nevertheless, the FAA's directive applies to all aircraft equipped with the engines in question, regardless of their hours of service. The agency explained that it did not have sufficient evidence to narrow the scope of its order as Continental had suggested.
Cirrus is Duluth's largest manufacturer, employing more than 1,200 people locally.
When asked about the impact of the engine issues on production, Cirrus officials responded: "We had a limited number of affected engines within our production line and do not anticipate the issue to have a significant effect on our 2023 production plans."
The Duluth-based airplane maker is coming off its biggest-ever year of sales, shipping 629 aircraft worth more than $765.4 million in 2022, according to GAMA. In terms of aircraft production, that's a 19.1% increase over the previous year. Meanwhile, the company's total billings were up $132.5 million from 2021 — a 20.8% bump.
Founded in Baraboo, Wisconsin, by brothers Alan and Dale Klapmeier, Cirrus got its start in 1984 but has been based in Duluth since 1994. Cirrus was purchased by China Aviation Industry General Aviation Co., a division of the state-owned Aviation Industry Corp. of China, in 2011.
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