Incident Overview
The aircraft, operating from Provo, Utah, conducted an ILS approach to runway 18 at Jackson Hole Airport. The runway is 6,299 feet long and 150 feet wide, with a gradient of -0.611% and was contaminated with ice. The approach was performed with a 6.5 knot tailwind.
Landing and Braking
During the landing roll, the captain engaged the emergency braking system. According to the manufacturer's Airplane Flight Manual (AFM), activation of emergency braking deactivates the anti-skid protection. The cockpit voice recorder (CVR) captured a high-pitch sound at 0839:44, consistent with the high-pressure air of the emergency braking system being activated.
Runway Excursion
After the aircraft touched down, it slid left, then right, and subsequently left again before returning to the runway centerline. The captain reported continued braking. The aircraft eventually departed the end of the runway, traveling 160 feet beyond into snow approximately 2 feet deep.
AFM Limitations for Contaminated Runways
The AFM specifies restrictions for landings on contaminated runways, which include: (A) winds must be zero or a headwind of less than 30 knots (i.e., no tailwind); (B) the runway gradient must be between -1% and +2.2%; and (C) the anti-skid system must be operational. In this incident, the tailwind, runway gradient, and use of emergency braking (deactivating anti-skid) did not meet these requirements.
Notes
The thrust reversers were mechanically pinned in the forward thrust position prior to departure from Provo, Utah. No further details are available regarding the aircraft type, registration, occupants, or injuries.