ASN Wikibase Occurrence # 321292
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| Date: | Wednesday 16 June 2010 |
| Time: | 14:30 |
| Type: |  Embraer EMB-145LR (ERJ-145LR) |
| Owner/operator: | United Express |
| Registration: | N847HK |
| MSN: | 14500857 |
| Year of manufacture: | 2004 |
| Total airframe hrs: | 14782 hours |
| Cycles: | 13829 flights |
| Engine model: | Rolls-Royce AE3007A1 |
| Fatalities: | Fatalities: 0 / Occupants: 36 |
| Aircraft damage: | Substantial, repaired |
| Category: | Accident |
| Location: | Ottawa/Macdonald-Cartier International Airport, ON (YOW) -
 Canada
|
| Phase: | Landing |
| Nature: | Passenger - Scheduled |
| Departure airport: | Washington-Dulles International Airport, DC (IAD/KIAD) |
| Ottawa-Macdonald-Cartier International Airport, ON (YOW/CYOW) | |
| Investigating agency: | TSB |
| Confidence Rating: |  Accident investigation report completed and information captured |
United Express Flight 8050 (LOF8050), an Embraer EMB-145LR regional jet, operated by Trans States Airlines, departed Washington-Dulles International Airport (KIAD) at 13:26 on a regularly scheduled flight to the Ottawa/MacDonald-Cartier International Airport (CYOW), Canada. On board were 33 passengers, 2 pilots, and 1 flight attendant. The first officer was the pilot flying.
The crew briefed for an ILS approach for runway 07 at Ottawa. The aircraft was vectored by ATC to a base leg at approximately 10 nautical miles. At 14:26, ATC advised the crew that the wind was 160° at 10 knots gusting to 16 knots, with a visibility of 10 sm in light rain.
During the final turn to intercept the localizer, the airport controller informed the crew that they were in the process of switching the active runway to runway 14. The crew was given the option of continuing for runway 07 or switching to runway 14. Considering the increased flight time, the extra fuel that would be used to manoeuver the aircraft for runway 14, and the fact that the aircraft was already established on approach to runway 07, the crew elected to continue for runway 07.
The final approach course was intercepted at 7 nm. The aircraft began its final descent upon interception of the glideslope, at a position approximately 4.7 nm from the threshold, with the autopilot coupled. Nearing the final approach fix, 3.9 nm from the threshold, the landing gear was extended, the landing flaps were selected to 22°, and the autopilot was disconnected. At approximately 1000 feet agl and 2.9 nm from the threshold, the airspeed was stable at 150 knots indicated airspeed (KIAS). Shortly thereafter, the windshield wipers were turned on, and the crew indicated that they had the runway in sight.
When the aircraft descended through approach minimums, 200 feet agl and 0.3 nm from the threshold, the airspeed was 144 KIAS. The aircraft crossed the threshold of runway 07 at 49 feet agl, at a speed of 139 KIAS. The aircraft did a very smooth touchdown, and the weight on wheels (WOW) switch momentarily activated at 14:30:15, 1740 feet from threshold. At that point, the nose was still in the air, and the aircraft floated. Two seconds later, 2270 feet from the threshold and at a speed of 132 KIAS, the second WOW activated and the nose wheel came down.
The first officer was depressing the brake pedals during the second WOW activation; all spoilers automatically deployed after the nose wheel was lowered to the ground. The first officer continued to apply brakes until maximum braking was commanded. Sensing a lack of deceleration, the first officer informed the captain, who then took control of the aircraft and applied maximum braking as well. The aircraft could not be slowed during brake application.
The aircraft was on the centreline until approximately 200 feet before the end of the runway, where it veered left. The aircraft exited the paved surface of the runway at approximately 62 KIAS. It continued through the grass for approximately 120 feet, at which point there was a sharp downward change in elevation of about 2 feet. The nose gear collapsed rearward, but the aircraft continued to skid. It came to a rest 550 feet from the end of the runway and 220 feet left of centreline. The flight attendant initiated the evacuation procedure for the passengers.
FINDINGS AS TO CAUSES AND CONTRIBUTING FACTORS:
1. The crew calculated an inaccurate VAPP (i.e., target approach speed), and flew the approach faster than recommended.
2. The aircraft crossed the threshold 8 knots above VREF (i.e., threshold crossing speed), resulting in an extended flare to a touchdown of 2270 feet, which was 770 feet beyond the Trans States Airlines (TSA) desired touchdown point of 800 to 1500 feet, but within the first third of the available landing distance as per TSA standard operating procedures.
3. The smooth landing on a wet runway led to viscous hydroplaning, which resulted in poor braking action and reduced aircraft deceleration, contributing to the runway overrun.
4. Rainwater accumulated on Runway 07/25 due to the crosswind and the design of its transverse slope, resulting in a further decline in the coefficient of friction for the occurrence flight.
5. The crew did not select flaps 45, as encouraged by Trans States Airlines standard operating procedures for landing on a wet, ungrooved runway, which resulted in a higher landing speed and a longer landing distance.
6. The crew did not initiate a go-around when VREF was exceeded by more than 5 knots indicated airspeed.
7. The antiskid brake system operated as designed, by keeping the brake pressures from rising to commanded values after brake application in order to prevent the wheels from locking. With little braking action during the landing roll, the aircraft overran the runway.
8. The aircraft overran the runway threshold and the runway strip, and subsequently encountered a significant dip, where the nose landing gear folded rearward, resulting in substantial damage to the nose of the aircraft.
Accident investigation:
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Sources:
Location
Images:
photo (c) TSB; Ottawa/Macdonald-Cartier International Airport, ON (YOW/CYOW); 16 June 2010
photo (c) TSB; Ottawa/Macdonald-Cartier International Airport, ON (YOW/CYOW); 16 June 2010
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