On September 4, 2011, an Embraer ERJ-145 (registration N840HK) operated by United Express was involved in an aviation accident near Ottawa-Macdonald-Cartier, Canada during landing or approach. No fatalities were reported. Investigators recorded the probable cause as: The aircraft lost directional control as a result of hydroplaning and veered off the runway. Contributing factors included heavy rainfall resulting in a 4–6 mm layer of water contaminating the runway, airspeed during final approach exceeding company… This summary draws on records from the Bureau of Aircraft Accidents Archives (B3A); 15 related events involving the same aircraft type or operator are linked below.
United Express Flight 3363, operated by Trans States Airlines, hydroplaned and veered off Runway 32 at Ottawa/Macdonald-Cartier International Airport after a wet-weather ILS approach. Passengers evacuated after a fuel leak was discovered.
Departure and Approach Planning United Express Flight 3363, operated by Trans States Airlines LLC, departed Chicago O’Hare International Airport at 1406. Before descending into Ottawa/Macdonald-Cartier International Airport (CYOW), the crew obtained ATIS information Yankee, issued at 1411, which identified Runway 25 as active. Based on the reported wind, the crew calculated an approach speed of 133 KIAS. However, due to a previous overrun on Runway 07/25 in August 2010, Trans States Airlines prohibited landings and takeoffs on that runway when the surface was damp or wet. With rain showers forecast and Runway 32 being the longest runway, the crew decided at 1506 to conduct an ILS approach to Runway 32. ## Approach and Touchdown At 1524, the CYOW terminal controller advised that heavy rain had started. About two minutes later, the aircraft intercepted the glideslope for Runway 32. The crew extended the landing gear and selected 22° of flaps. The tower reported moderate rain and wind from 310°M at 10 knots. The aircraft crossed the GREELY (YYR) final approach fix at 4.3 nm, slightly above the glideslope at 174 KIAS. Around 1528, the aircraft passed through 1,000 feet agl at 155 KIAS, and the flaps were then selected to 45°. The airspeed was approximately 145 KIAS. The tower advised that the wind had changed to 320°M at 13 knots gusting to 20 knots, and the crew increased the approach speed to 140 KIAS. At 1529, the aircraft crossed the Runway 32 threshold at about 45 feet agl and 139 KIAS. As rain intensity increased, the crew selected the windshield wipers to high. At about 20 feet agl, engine power was reduced and a flare was commenced. Just before touchdown, a downpour obscured the crew’s view of the runway. Perceiving a sudden increase in descent rate at approximately 5 feet agl, the captain applied maximum thrust on both engines. The master caution light illuminated, and a voice warning stated that the flaps were not in a take-off configuration. Maximum thrust was maintained for 7 seconds. The aircraft touched down smoothly 2,700 feet beyond the threshold at 119 KIAS, with airspeed increasing, and became airborne again. It touched down a second time at 3,037 feet beyond the threshold, with airspeed increasing through 125 KIAS. Airspeed peaked at 128 KIAS as the nosewheel was lowered to the ground, and the thrust levers were retarded to flight idle. The outboard spoilers deployed almost immediately, and the inboard spoilers deployed about 8 seconds later. The aircraft was about 20 feet right of the runway centreline at the second touchdown. Once the nosewheel was on the ground, the captain applied maximum brakes. The crew almost immediately noted that the aircraft began skidding, and the captain requested the first officer to apply maximum brakes as well. No significant brake pressure was recorded until about 14 seconds after the outboard spoilers deployed, when brake pressure suddenly increased to its maximum. During this time, the captain attempted to steer the aircraft back to the runway centreline. As the aircraft skidded, it began to yaw to the left. Full right rudder was applied but was ineffective. Sufficient water on the runway surface caused the tires to send a spray of water, commonly known as a rooster tail, to a height of over 22 feet, trailing over 300 feet behind the aircraft. At some point during the landing roll, the captain partially applied the emergency/parking brake (EPB), and when no braking action was felt, the EPB was engaged further. With no perceivable deceleration, the EPB was stowed. The aircraft continued to skid down the runway until about 7,500 feet from the threshold, at which point it started skidding sideways. At 1530, the nosewheel exited the paved surface, 8,120 feet from the threshold, at approximately 53 knots, on a heading of 271°M. The aircraft came to rest on a heading of 211°M, just off the left side of the paved surface. ## Post-Impact Actions After coming to a stop, the flight crew carried out the emergency shutdown procedure as per the company Quick Reference Handbook (QRH) and consulted with the flight attendant on the status of everyone in the passenger cabin. The crew determined that there was no immediate threat and decided to hold the passengers on board. When the aircraft exited the runway surface, the tower activated the crash alarm. CYOW airport rescue and firefighting (ARFF) services responded and were on scene approximately 3 minutes after the activation of the crash alarm. Once ARFF personnel had conducted a thorough exterior check of the aircraft, they informed the flight crew that there was a fuel leak. The captain then called for an immediate evacuation of the aircraft. The passengers evacuated through the main cabin door and moved to the runway as directed by the flight crew and ARFF personnel. The evacuation was initiated approximately 12 minutes after the aircraft came to a final stop. After the evacuation was complete, the firefighters sprayed foam around the aircraft where the fuel had leaked.
Probable cause
The aircraft lost directional control as a result of hydroplaning and veered off the runway. Contributing factors included heavy rainfall resulting in a 4–6 mm layer of water contaminating the runway, airspeed during final approach exceeding company prescribed limits for stabilized approach criteria, a go-around not being performed when the aircraft’s speed was greater than 5 knots above the appropriate approach speed, the application of engine thrust just before touchdown causing the aircraft to touch down 3,037 feet from the threshold at a higher than recommended airspeed, a less than firm landing and underinflated tires contributing to hydroplaning, and the application of the emergency/parking brake during the landing roll, which disabled the anti-skid braking system and prolonged the skid.