Installed Backward: The FAA's New Order for Thousands of AS350 and EC130 Helicopters
The Federal Aviation Administration has ordered inspections of thousands of Airbus AS350 and EC130 helicopters after learning that a small metal flange inside the aircraft's main gearbox coupling can be installed backward on the factory line — a mistake the agency says could, in the worst case, sever the connection between the engine and the main rotor in flight.
The directive, numbered 2026-16-01, takes effect September 10, 2026, and applies to Airbus Helicopters Model AS350B, AS350BA, AS350B1, AS350B2, AS350B3, and AS350D helicopters built before May 15, 2023, along with EC130B4 and EC130T2 models built before February 13, 2023. The AS350 and its variants — sold widely as the "Ecureuil" or "Squirrel" family, and marketed in North America partly as the AStar — are among the most common single-engine helicopters in commercial service, used for everything from tour flights over the Grand Canyon and Hawaii to air ambulance work, utility patrol, and law enforcement.
It is one of two new FAA directives targeting incorrectly assembled components published in the same Federal Register issue on August 6, 2026, both taking effect the same day and both tracing back to a manufacturing "quality escape" — an industry term for a defect that slips past inspection and reaches a finished aircraft.
What the FAA Found
According to the directive text, the unsafe condition centers on the main gear box (MGB) engine coupling, the component that transmits power from the helicopter's turbine engine into the transmission driving the main rotor. The FAA says it received reports of an "incorrectly installed engine flange" on that coupling — installed inverted, rather than in its intended orientation.
"The unsafe condition, if not detected and corrected, could result in the loss of power transmission to the MGB and the main rotor and lead to loss of control of the helicopter," the FAA wrote in the directive.
The American AD adopts, with several technical modifications, an existing directive issued by the European Union Aviation Safety Agency — EASA AD 2023-0127, dated June 27, 2023 — meaning European regulators identified the defect and ordered corrective action more than three years before the FAA's mandate takes effect in the United States. The FAA's version requires owners to use hours of time-in-service rather than flight hours as the compliance clock, and requires any nonconforming flange to be permanently removed from service rather than simply flagged, among other adjustments to the European original.
Operators are directed to inspect the MGB engine coupling for correct flange orientation and, where a flange is found installed backward, to take corrective action before further flight. The FAA is not requiring operators to report inspection results back to Airbus Helicopters, a reporting step that the EASA version had called for.
A Second Directive, Same Day
Published alongside the AS350/EC130 order is AD 2026-16-02, covering Bell Textron Canada's Model 505 — a newer light single-engine helicopter marketed as the Jet Ranger X's successor and popular in flight training and private ownership. That directive was prompted by a different defect: a washer installed in the wrong location on the tail rotor pitch link assembly during production.
The FAA warns that the misplaced washer could allow the pitch horn stud to fracture from fatigue, or when the rotor blade exceeds its normal range of travel during certain control inputs — a failure the agency says could cause loss of directional control of the aircraft. The directive, which stems from Transport Canada AD CF-2025-34, requires a one-time visual inspection of the pitch link assembly and, where the washer is misplaced, disassembly and correction.
The FAA's published cost estimate for the Bell 505 order gives a rare window into what these fleet-wide fixes actually cost operators. The agency estimates the AD affects 10 helicopters on the U.S. registry. A baseline inspection runs about $85 in labor per aircraft — roughly $850 total across the affected U.S. fleet. But if an inspection turns up a misassembled unit requiring full replacement of the pitch link assembly, tail rotor pitch horn, packings, and conical washer, the FAA estimates the cost could run as high as $9,472 per helicopter, split between roughly $340 in labor and $4,396 in parts per assembly — potentially doubled if both sides need replacement. The FAA notes some of that cost may ultimately be covered under manufacturer warranty.
No comparable cost table was published for the AS350/EC130 directive, and the FAA's public filing does not state how many U.S.-registered helicopters fall under that order — a gap that will likely become clearer once the agency's cost-benefit docket for AD 2026-16-01 is made public in full.
Why Both Defects Trace to Production, Not Wear
Neither directive describes an in-service failure caused by fatigue, corrosion, or age. Both describe assembly-line errors: a flange installed in reverse, a washer placed in the wrong spot. That distinction matters for how operators and passengers should read the news. These are not directives responding to an accident, and neither the FAA's filing for the AS350/EC130 order nor the Bell 505 order references an in-flight loss-of-control event. They are preventive measures — the FAA and its counterpart regulators identifying a manufacturing defect through routine reporting and moving to catch it in the existing fleet before it causes one.
That said, the stakes described in the FAA's own unsafe-condition language are serious by design: loss of power transmission to a helicopter's main rotor, or loss of directional control via the tail rotor system, are among the most severe failure modes a helicopter can experience, because unlike a fixed-wing aircraft, a helicopter typically has far less time and altitude to recover from a sudden loss of rotor authority.
Who Is Affected
The AS350 family is in especially wide use. Beyond tour and utility operators, it is a mainstay of hospital air ambulance fleets in the U.S. and law enforcement air units in major cities, and it has been manufactured for decades, meaning the population of aircraft built before the May 2023 and February 2023 cutoff dates in the directive is substantial — encompassing most of the AS350/EC130 fleet flying today, since the cutoff dates fall only a few years into the past relative to a helicopter type that has been in continuous production since the 1970s.
Operators of affected aircraft have until the directive's specified compliance times — set by reference to the underlying EASA directive — to complete the inspection. Alternative methods of compliance can be requested through the FAA's International Validation Branch. Owners with questions about the AS350/EC130 order have been directed to contact FAA Aviation Safety Engineer Aryanna Sanchez in Westbury, New York; questions about the Bell 505 order go to Aviation Safety Engineer David Enns at the same office.
Both directives were issued under the signature of Steven W. Thompson, Acting Deputy Director of the FAA's Compliance & Airworthiness Division, and neither drew public comment during the rulemaking process — the Bell 505 directive's docket shows the agency received no comments on either the proposed rule or its cost estimates before finalizing it.