Incident Overview
On October 5, 2022, at 1859 eastern daylight time, Air Wisconsin flight 3318, a Bombardier CL-600-2B19 (registration N447AW), sustained minor damage during a runway excursion after landing on runway 24L at James M. Cox Dayton International Airport (DAY), Dayton, Ohio. The flight was a Title 14 Code of Federal Regulations Part 121 scheduled domestic passenger service from Dulles International Airport (IAD), Dulles, Virginia, to DAY. The three crewmembers and 42 passengers aboard were not injured.
Flight Sequence
The captain was the pilot flying and the first officer was the pilot monitoring. Flight data recorder (FDR) data indicated that the airplane touched down at an airspeed of about 127 knots. After main gear touchdown, the spoilers deployed, wheel braking on both main gear brakes increased, and the airplane tracked along the runway heading for about 9 seconds, with an initial deceleration rate of about 5 knots/second. The cockpit voice recorder (CVR) captured a sound consistent with nosewheel tires rolling over runway grooves beginning when the nosewheel touched down, approximately 1 to 2 seconds after main gear touchdown.
About 3 seconds after nosewheel touchdown, both thrust reversers were deployed. The left thrust reverser remained deployed for about 6 seconds, and the right for about 4 seconds. During deployment, left engine thrust peaked at about 57% N1 and right at about 70% N1.
The captain reported navigating the airplane along the runway centerline during the initial rollout. FDR data showed lateral acceleration began increasing (consistent with a right turning tendency) 1-2 seconds before the thrust reversers began to stow. The captain stated that as he started to stow the reversers, the airplane began veering to the right. FDR data indicated that as the reversers stowed at a groundspeed of about 97 knots, the magnetic heading began to increase. The captain applied left rudder pedal and differential braking toward the left, but these actions did not counteract the rightward movement. The first officer also applied braking when departure became apparent.
The airplane departed the runway surface about 12 seconds after nosewheel touchdown, traveled through grass alongside the runway, and came to rest on an adjacent taxiway.
Weather and Runway Conditions
At 1856, reported weather at DAY included wind from 350° at 3 knots (a right crosswind), visibility 10 miles, and scattered clouds at 25,000 ft. The operator reported the runway was dry.
Pilot Actions and Aircraft Response
A review of the CVR revealed no aural alerts during the landing. The nosewheel tire noise continued for about 12 seconds. FDR data showed no system fault indications. The FDR did not record nosewheel steering angle or commanded nosewheel steering position. The rudder was deflected 2° to the right for less than 1 second, followed by two successive left deflections (5° and 4°). Lateral acceleration began increasing coincident with the first rudder deflection. Brake pressure increased equally on all four main gear wheels to about 500-600 psi before the left rudder deflections, then differential braking applied: left outboard wheel pressure increased to about 1,900 psi, right inboard to about 1,100 psi then briefly 1,400 psi. The average brake pressure on left main gear exceeded that on the right by 440 to 720 psi. The airplane departed the runway at a groundspeed of about 57 knots and a heading of 260°, 19° right of the runway heading (241°). The airplane made a continuous right turn from the start of the turn until it came to rest.
Post-Incident Examination
After stopping, the captain noted the No. 1 (left outboard) brake temperature monitor showed 7 on a scale of 0 to 20; the other three monitors were no higher than 5. No brake overheat warning was triggered. The higher temperature was consistent with higher braking pressure on the left outboard wheel. No warning, caution, or abnormal indications appeared on flight deck displays. Tire marks on the runway curved to the right, with six distinct marks. Post-incident examination of the rudder and nosewheel steering systems revealed no anomalies. The airplane sustained minor impact damage to the left wingtip and a puncture in the left wing’s leading edge. A taxiway sign near taxiway G was damaged. A review of FDR data from three previous landings showed that right engine thrust in reverse was slightly higher (5% to 15% N1) than left engine thrust during portions of deployment, with the second previous landing most similar to the incident.