The FAA proposes a Challenger 300 family flight-manual change. The rule would cover all Bombardier BD-100-1A10 aircraft. That type certificate spans the Challenger 300, Challenger 350 and Challenger 3500. Comments close on 29 October 2026.
The unsafe condition sits with the autopilot's stabiliser trim. Operators reported pitch upset on autopilot disconnect. In each case, engine indication and crew alerting messaging had already flagged that the autopilot was holding significant nose-up or nose-down forces on the elevator. Delay in responding leaves the aircraft with a mistrimmed stabiliser when the autopilot drops out.
The proposed remedy is procedural. The aircraft flight manual would move the AP STAB TRIM FAIL (C) advisory from a non-normal procedure to an emergency procedure. Crews would then apply emergency steps to stabilise airspeed before the autopilot disconnects.
The FAA estimates 680 US-registered aircraft are in scope. Direct compliance is one work-hour at $85 per operator. Aggregate fleet cost across the US register is $57,800. Parts cost is zero. Operators can file comments through the docket during the 45-day window.
The proposal adopts Transport Canada AD CF-2025-42 by reference, dated 26 August 2025. The notice appeared in the Federal Register on 14 September 2026 as document 2026-18746 under docket FAA-2026-8808. It is one of several Bombardier procedural updates the FAA has advanced in 2026, following the CL-600 series flap-movement AD earlier in the year. Owners of Challenger 300, 350 and 3500 aircraft should schedule the flight-manual revision alongside the next AFM update. Operations departments should route the new emergency drill into recurrent training.
Source: Federal Register document 2026-18746, FAA NPRM, 14 September 2026; Transport Canada AD CF-2025-42, 26 August 2025.