CHI04IA056

The airplane, being operated on a scheduled passenger flight, contacted the runway with the left wing tip, following a loss of control while landing. Weather conditions were varying due to freezing fog that was moving into and out of the area. The control tower at the destination airport was closed and the airplane was being controlled by a near-by approach control facility. After holding in-flight to wait for the weather to improve, the crew began the instrument landing system (ILS) approach when the visibility was reported as one-half mile. The captain stated that almost immediately upon entering the top of the fog layer they received an ICE caution message. He stated they turned on the wing and engine inlet anti-ice, but the ice accumulation on the windshield wipers was rapid and ice was accumulating on the winglet. The captain stated the approach lights came into sight when they were just above minimums and that he had the runway in sight at approximately 140 feet above the ground. The first officer then disconnected the autopilot and the nose came up slightly. He stated he informed the first officer to keep the nose down and add thrust. The captain stated they were slightly left of the centerline and the first officer was making "small" corrections back to the right. He stated the airspeed was just inside the "bottom of the bucket" and the trend vector was indicating a decrease in airspeed. The captain stated he "again said something about more thrust and keeping the nose down." He stated the airplane continued to move to the right of the centerline and he took control of the airplane. He stated the airplane responded "poorly" feeling "heavy and sluggish." The captain stated the airplane was close to the right side of the runway and he added thrust at which time the ailerons became more responsive. He stated the left wing dropped, scraping the runway, at about the same time the left main gear touched down. The captain stated the airplane bounced into the air then landed hard on the runway. The crew then taxied the airplane to the gate. The first officer stated that when the captain reported having the runway in sight, she transitioned her sight outside of the airplane and realized she needed to correct to the right. She stated she began the correction at which time the nose of the airplane pitched up, the airplane veered toward the correction, and it started sinking toward the right side of the runway. She stated the captain took over the controls, but the airplane dropped to the runway, bounced, and touched down harder the second time. The first officer, who was flying the approach, had about 15 hours of total flight time in the CL-600. The captain, who was also a check airman, had a total of 1,196 hours of flight time in the CL-600. At the time of the accident the local weather was reported as being visibility 1/4 mile in freezing fog, vertical visibility 100 feet. Inspection of the airport and airplane on the afternoon following the incident revealed ice was still visible on the antennas, windshield wipers, radome, winglets, and horizontal and vertical stabilizers. The main body of ice on these structures measured between one-half to five-eights of an inch thick and that the main body of ice plus the "ice spines" totaled three-quarters of an inch thick. A Kinematic parameter extraction showed loss of lift consistent with airframe icing but there was no early stall due to icing prior to touchdown and no indication that airframe icing had caused any loss of control. Marks on the ground and on the runway revealed the airplane initially touched down 1,976 feet from the approach end of the runway with the right main landing gear in the grass off the side of the runway. The left wing tip then left a 63-foot long scrape mark on the runway, which was followed about 1,100 feet later by another set of tire marks. Data from the flight data recorder showed the airplane rolled slightly to the left followed by a roll to the right when the autopilot was disengaged. It then showed the airplane touched down with a vertical acceleration of at least 1.8g's. The airplane then became airborne in a 16-degree left bank, with a 5-degree nose up pitch at which time the ground and flight spoilers deployed contributing to the firmness of the 3.25 g touchdown one second later.

History of flight

On January 17, 2004, at about 2211 mountain standard time, a Bombardier CL-600-2B19, operated by Skywest Airlines, as flight 3855, contacted the runway with the left wing tip, while landing on runway 32 (8,701 feet by 150 feet, dry concrete) at the Rapid City Regional Airport (RAP), Rapid City, South Dakota. The airplane received minor damage to the wing tip. The captain, first officer, flight attendant, and 32 passengers were not injured. The 14 Code of Federal Regulations Part 121 scheduled passenger flight was operating in instrument meteorological conditions on an instrument flight rules (IFR) flight plan. The flight originated from Salt Lake City, Utah, at 2035.

The captain reported that during their initial descent the RAP automated surface observing system (ASOS) was reporting the weather conditions as being clouds broken at 100 feet and overcast at 500 and 1 1/2 statute (sm) miles visibility. He stated the ASOS was also reporting that the ceiling was varying between 100 and 600 feet. He stated they set up for the instrument landing system (ILS) runway 32 approach and a few minutes later Ellsworth Approach Control reported the visibility had decreased to 1/2 mile in freezing fog. The captain stated that the controller asked them what their intentions were at which time they requested vectors for the approach.

The captain stated that a minute or two later the controller reported the visibility decreased to 1/4 mile with freezing fog. He stated they informed the controller that due to the decreased visibility, they were unable to make the approach and they requested holding instructions. He stated they were issued a hold at the outer marker, RANCH. He stated that as they entered the hold, he switched radios and informed dispatch that they were going to be delayed. The captain stated that the first officer then informed him that Ellsworth approach control was now reporting the RAP visibility as being 1/2 mile. He stated they asked for and received vectors for the approach. He stated they were informed that the RAP tower was closed and they would be unable to receive runway visual range (RVR) information.

The captain stated they turned on the auxiliary power unit (APU) and configured the bleed air system in anticipation of encountering icing conditions when they descended through the fog layer. He stated they were cleared for the approach and almost immediately upon entering the top of the fog layer they received an ICE caution message. He stated they turned on the wing and engine inlet anti-ice, but the ice accumulation on the windshield wipers was "quite rapid."

The captain stated that as the approach progressed he became concerned about the amount of ice accumulating on the windshield wipers. He stated he looked out the side window and although he was unable to tell the quantity, he saw ice accumulating on the winglet. He stated that he then began calculating how much fuel they had remaining and how long they would be able to hold before continuing to their alternate.

The captain stated they continued the approach and the first officer called "500 to minimums." He stated that just above minimums the approach lights came into sight and he had the runway in sight at approximately 140 feet above the ground. The first officer then disconnected the autopilot at which time the nose came up slightly. He stated he informed the first officer to keep the nose down and add thrust. The captain stated they were slightly left of the centerline and the first officer was making "small" corrections back to the right. He stated the airspeed was just inside the "bottom of the bucket" and the trend vector was indicating a decrease in airspeed. He stated he "again said something about more thrust and keeping the nose down." He stated the airplane continued to move to the right of the centerline and he took control of the airplane. He stated the airplane responded "poorly" feeling "heavy and sluggish." The captain stated the airplane was close to the right side of the runway and he added thrust at which time the ailerons became more responsive. He stated the left wing dropped, scraping the runway, at about the same time the left main gear touched down. The captain stated the airplane bounced into the air then landed hard on the runway. The crew then taxied the airplane to the gate.

The first officer stated that when the captain reported having the runway in sight, she transitioned her sight outside of the airplane and realized she needed to correct "slightly (about a foot)" to the right. She stated she began the correction when the nose of the airplane pitched up, the airplane veered toward the correction, and it started sinking toward the right side of the runway. She stated the captain took over the controls, but the airplane dropped to the runway, bounced, and touched down harder the second time. She stated she believes the wingtip scraped the runway. The first officer stated that a post flight inspection of the airplane revealed "large amounts of 1/2 to 1 inch thick jagged mixed ice all along the vertical and horizontal stabilizer, as well as, up the leading edge of the wingtips and several silver dollar size balls of ice on the static wicks."

Personnel information

Information provided by SkyWest Airlines indicated the first officer, who was flying the approach, had approximately 15 hours of total flight time in a CL-600. The captain, who was also a check airman, had a total of 1,196 hours of flight time in a CL-600.

Meteorological information

The RAP weather recorded at 2142 was: wind 070 degrees at 7 knots, visibility 1 1/2 statute miles in mist; broken clouds at 100 feet, overcast clouds at 500 feet, temperature -1 degree Celsius, dew point -2 degrees Celsius, and altimeter 30.12 inches of Mercury (Hg).

The RAP weather recorded at 2152 was: wind 070 degrees at 7 knots, visibility 1/4 mile in freezing fog, vertical visibility 100 feet, temperature -1 degree Celsius, dew point -2 degrees Celsius, and altimeter 30.13 inches of Hg.

The RAP weather recorded at 2203 was: wind 080 degrees at 5 knots, visibility 1/2 mile in freezing fog; vertical visibility 100 feet, temperature -1 degree Celsius, dew point -2 degrees Celsius, and altimeter 30.13 inches of Hg.

The RAP weather recorded at 2211 was: wind 070 degrees at 6 knots, visibility 1/4 mile in freezing fog, vertical visibility 100 feet, temperature -2 degrees Celsius, dew point -2 degrees Celsius, and altimeter 30.13 inches of Hg.

The RAP weather recorded at 2242 was: wind 060 degrees at 8 knots, visibility 1 mile in mist, vertical visibility 200 feet, temperature -2 degrees Celsius, dew point -3 degrees Celsius, and altimeter 30.14 Hg.

There were no current Severe Weather Alerts, Convective SIGMETs, SIGMETs, or Center Weather Advisories over RAP at the time of the incident.

A pilot who was flying a Piper PA-24-250 that landed at RAP 5 to 7 minutes prior to SkyWest 3855 stated the weather was changing rapidly during the evening. He stated that fog was rolling into and out of the airport. This pilot stated he began picking up a trace of ice when he entered the clouds during the approach. He stated the icing conditions worsened rapidly as he continued the descent. He stated the ceiling was about 1,000 feet and the visibility was about 6 miles when he touched down. The pilot stated he picked up so much ice on his airplane that it stalled 3-feet above the runway at an airspeed of 90 knots. He stated he heard SkyWest 3855 land as he approached his hangar on the north end of the airport; however, he was unable to see the airplane due to the rapidly decreasing visibility. This pilot stated that his airplane accumulated so much ice during the approach that the leading edge of the wings were no longer cambered, but rather they were flat due to the ice buildup. He stated he would not have been able