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The Pilatus PC-24, a light business jet, is the subject of a new FAA AD (2026-17-11), published Sept. 15, that takes effect Oct. 20. Not all airplanes are affected. The directive requires modification of the aircraft and replacement of the solid-state relay in the left windshield heating system with a serviceable part. Operators of aircraft with the old relay installed have 16 months from the effective date to complete the work. Regulators determined that a specific solid-state relay can permit reverse current flow when switched off. If both generators fail, that condition could prevent the emergency windshield heat from performing as intended, potentially resulting in loss of outside visibility in icing conditions, when it is most needed. The FAA adopted the rule after EASA issued AD 2026-0008 in January, requiring the corrective action in Pilatus Service Bulletin 30-007. The agency received no comments on the proposal after publishing the NPRM in May 2026. The issue may be technical, but the solution is administrative as much as mechanical. Operators, management companies and maintenance providers now need to determine whether aircraft are affected and schedule the required work into future maintenance visits. The AD specifically covers PC-24s with serial numbers 101 through 337 that have Pilatus SB 30-004 or SB 30-006 embodied at original issue, plus serial numbers 501 through 590. Aircraft with either bulletin at Revision 1 or later embodied are not affected. The affected relay is part number 974.20.01.234, and the serviceable replacement is 974.20.01.235. The FAA estimates the AD affects 168 U.S.-registered aircraft. For 125 of them, the work covers the relay and its cables, at about five hours of labor and $1,032 in parts, or $1,457 per aircraft. The other 43 need only the relay, at 2.5 hours and $32 in parts, or $244.50 per aircraft (the AD does not say what separates the aircraft needing relay and cables from those needing the relay alone). The manufacturer says warranty may cover some of the cost. What operators need to know The out-of-pocket cost is small. The required work is a one-time modification and replacement, with no recurring inspection and no reporting requirement. The old relay may not be installed on the left side after the work. The 16-month compliance window closes around Feb. 20, 2028, which leaves room to fold the work into a scheduled maintenance visit.