The Federal Aviation Administration has ordered operators of Swearingen Metroliner and Merlin turboprops to inspect, time and, if necessary, replace the pitch trim actuator on a repeating schedule, after six reports of the part failing in flight. The directive, numbered 2026-21-13, was published on October 27, 2026 and takes effect on December 1. It applies to 198 airplanes on the U.S. registry.
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Pitch trim is the system that holds a plane’s nose angle steady so a pilot is not leaning on the controls for the whole flight. When the actuator that drives it fails, the crew loses part of that control. The FAA says the cause here is mundane and slow: corrosion that builds up inside a sealed part until it stops doing its job.
Water inside drilled Simmonds-Precision piston rods
According to the FAA’s April 2 proposal, the failures traced to Simmonds-Precision actuators carrying part numbers DL5040M5, DL5040M6 and DL5040M8. The piston rod in those units is drilled through, which lets water reach the inside of the actuator body through the rod end keyway and the piston. The agency’s six reports all involved corrosion. The agency’s wording in the final rule is blunt about the consequence: the unsafe condition, if left alone, “could result in pitch trim actuator failure and reduced control of the airplane,” a line AvWeb lead editor Matt Ryan carried in his report on the directive. The FAA did not say which flights were involved or how the crews recovered, and nothing in the directive suggests an accident.
The directive sorts the affected airplanes into two groups. Group 1 covers the SA226-T, SA226-AT, SA226-T(B), SA226-TC, SA227-AC, SA227-AT, SA227-BC, SA227-PC and SA227-TT, while Group 2 is the SA227-CC and SA227-DC. The military C-26A and C-26B designations fall inside those lists. Only airplanes fitted with one of the three named actuator part numbers are covered, so an airplane with a different trim actuator is outside the order even if the model name matches.
What operators must do, and when
The directive in the Federal Register splits the work into two checks. The first is a look at the sealant around the rod ends, repeated every 1,000 flight hours or 12 months, whichever comes first. The second is a travel-time measurement, in which a mechanic times how long the actuator takes to run through its full stroke; that repeats every 250 or 300 flight hours, or every six months, depending on the part number and whether the nut tube assemblies were replaced.
The first inspection falls due at the later of 30 days after the December 1 effective date or 1,000 flight hours or six months after the actuator entered service, whichever comes first. A cracked, missing or compromised sealant on an actuator with at least 1,000 flight hours or six months of service means replacement before the next flight. A younger actuator can be inspected and resealed. Any actuator that fails the travel-time check must be replaced before further flight.
The directive also closes two loopholes. Special flight permits, which normally let an operator ferry an airplane with a known defect to a repair shop, are not allowed. And from December 1, an actuator can be installed only after the return-to-service steps in the manufacturer’s service bulletins, including sealing the rod ends once the part is rigged.
The bill the FAA expects
The agency’s cost table, reproduced in the public-inspection copy of the rule, prices each travel-time check or sealant inspection at three work-hours and $255 per airplane, or $50,490 across the 198-airplane U.S. fleet for each round. Resealing the rod ends adds about $319, including $149 in parts. A replacement actuator is the expensive item at roughly $20,425, nearly all of it parts. The FAA says it cannot estimate how many replacements will be needed, so the fleet-wide total is open-ended. For a small commuter or cargo operator running older Metroliners, the recurring cost is the inspection cycle itself, which now comes around more than once a year for the travel-time check.
Operators are not required to report their findings to the manufacturer, according to a summary of the final rule by AeroCorner, which also notes that Ontic Engineering and Manufacturing, the current type certificate holder, and the parts supplier World Class Accessory both commented on the proposal before it was finalized.
Service bulletins that predate the mandate
The service bulletins behind the directive date to November 2024 and January 2026, which means the manufacturer had a repair procedure in circulation well before the mandate. The proposal listed Ontic bulletins CC7-27-038R3, 227-27-067R2 and 226-27-087R2 as the approved method. What the filings do not show is how many of the 198 airplanes already carry sealed or replaced actuators, or whether any of the six in-flight failures happened on airplanes that had been inspected under earlier guidance. The FAA’s contact for questions is Trevor Carlton, an aviation safety engineer in the agency’s East Certification Branch in College Park, Georgia, and the answer to those gaps will come from the first round of inspection results after December 1.
This article was produced with the assistance of AI and reviewed by Morning Overview editors prior to publication.
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