The FAA has mandated a software update on the Pilatus PC-12/47E. The new airworthiness directive becomes effective on 14 July 2026. It targets the stall warning protection system on specific serial numbers.
During a manufacturer test flight, the system triggered at a higher airspeed than expected. The flight used flaps at 40 degrees with gravitational loads close to zero g. The aural warning, stick shaker and stick pusher all activated. If left unaddressed, the condition could reduce safety margins and pilot control authority.
The directive applies to manufacturer serial numbers 1720, and 2001 through 2476. Owners must update the Honeywell Primus Apex operational software on affected aircraft. They must also incorporate a Pilatus PC-12/47E pilot's operating handbook temporary revision. Installation of any affected software is prohibited going forward.
The FAA acted on EASA airworthiness directive 2025-0271. The European agency identified the unsafe condition first and issued the original directive. The US action follows the standard bilateral mechanism between EASA and the FAA on European-type designs. The Pilatus type certificate sits with EASA in Cologne, with the FAA validating through that route.
Pilatus produces the PC-12 at its Stans plant in Switzerland. The single-engine turboprop entered service in 1994 and is the most-delivered pressurised single in production. The 2,000th PC-12 was delivered in 2024. The newer PC-12 PRO uses a different Honeywell Primus Epic 2.0 cockpit and is not in scope. Owners of in-scope aircraft should schedule the software update with an authorised Pilatus service centre before the 14 July deadline to remain in compliance.
Source: FAA AD 2026-11528, Federal Register, 9 June 2026; GlobalAir; EASA AD 2025-0271.