NTSB Factual Report

HISTORY OF FLIGHT:

On December 16, at 1645 eastern standard time (EST), a Bombardier CRJ-200 (CL600-2B19), registration N470ZW, serial number 7927, operated by Air Wisconsin as flight 3758 (ATC call sign AWI758A), departed the runway after a hard landing at the Theodore Francis Green State Airport, Providence, RI (PVD). The flight was a regularly scheduled passenger flight which departed Philadelphia (PHL) at about 1600 EST. The First Officer, who had recently completed his Initial Operating Experience (IOE) in the CRJ-200, was the Pilot Flying (PF). This flight was the second time he had flown from Philadelphia to PVD, and the Captain, Pilot Not Flying (PNF), was aware that he was new to the airline. The accident flight was the fourth leg the crew had flown that day, the Captain was PF for the first two legs, and the FO flew the leg from Richmond into PHL. Instrument meteorological conditions prevailed for all of their flights that day.

The flight to the PVD area was reported as routine, with IFR weather enroute. Winds aloft in the vicinity of the initial descent were reported as from 220 degrees at 100 knots, resulting in a large tailwind component. Both crewmembers stated they felt rushed during the descent. The flight was cleared for and executed an ILS runway 5 approach. The airplane was initially established and stabilized on the localizer and glideslope. Approximately 2 miles from the runway threshold, at an altitude of 700 feet, the FO disconnected the autopilot and flight director (FD) and announced that he had disengaged the autopilot. In an interview he stated that he wanted to get the feel of the airplane, and "declutter" the display. At the time, Air Wisconsin procedures allowed hand flying raw data instrument approaches.

About 30 seconds later, the airplane drifted to the left of the approach course, and continued to descend, although above the glidepath. The airplane broke out of the overcast at 300’ and the crew saw the approach lights at the 2 o’clock position. The Captain offered to take over the airplane and the FO concurred. The Captain made a statement which the FO incorrectly heard as a command to reduce power to idle, and he did so, without the Captain’s knowledge. The Captain maneuvered the airplane in a series of descending banks, reaching a maximum bank angle of 22 degrees at a height of less than 100 feet above the runway. A descent rate of up to 2000 feet per minute developed. During the landing maneuver, pitch attitude decreased to 7 degrees nose down, then flared to 4 degrees nose up within five seconds just prior to touchdown. The captain increased power to about 73% N1 during the flare maneuver. Airspeed was approximately 132 knots at touchdown. Due to the flare rotation and sink rate, the airplane exceed the stall angle of attack, and the stall protection system (stick shaker and pusher) briefly activated. According to a performance study, the airplane touched down in about a nine degree left bank, heading about 049 degrees with a sink rate of approximately 18 feet per second.

The touchdown point was approximately 1000 to 1200 feet from the threshold of runway 5. The left main gear collapsed and the airplane exited the left side of the runway and slid through a snow-covered grassy area. The airplane came to a stop on a magnetic heading of approximately 320 degrees at about 3700 feet from the threshold. The 3 crew members and 31 passengers were not injured, and exited the airplane via the normal airstair door.

INJURIES TO PERSONS:

None.

DAMAGE TO AIRCRAFT:

The left main gear separated from the main landing gear support trunnion at the pivot assembly (pintle pin). The trunnion fractured, and the rear portion was forced upward and aft, bending the aft landing gear support "false spar" and separating it from the inner mounts. The wheel truck penetrated the flap and upper wing skin. Fractures in the upper wing skin of approximately 18" surrounded the penetration area. The aft main spar was bent in the vicinity of the forward support of the trunnion. The gear door was separated, and the door brace was broken. The main gear remained attached to the airplane by the actuator, and the actuator mounting supports were bent. The gear assembly itself was intact with scraping damage and cuts to the tires consistent with encountering the wing and flap components. Wing tip damage to the light and fairing was also observed. There was no fuel spill. The left engine had minor FOD damage causing numerous nicks and cuts to about 10 fan blades.

The airworthiness group examined the aircraft and landing gear components at PVD. The team found no evidence of fatigue cracking, corrosion damage, undue wear, arcing strikes or other damage on either the landing gear components or in the left hand MLG wheel well cavity.

The MLG mounting trunnion sustained a massive diagonal fracture, but remained attached to the wing structure. The trunnion pin (pintle pin) was sheared off and was seized in the housing. The trunnion parts were removed from the airplane for metallurgical examinations.

OTHER DAMAGE:

Three lights along the left side of runway 5 were broken when the airplane slid off the runway.

PERSONNEL INFORMATION:

The captain, age 30, was hired by Air Wisconsin (AWAC) on September 15, 2003. He held an Airline Transport Pilot certificate, multi-engine land, a commercial pilot certificate with an instrument-airplane rating, and was a certified flight instructor and instrument instructor. He had a CL-65 type rating and a BE-1900 type rating. He had a first class medical with vision correction required.

He had a total flying time of 5500 hours, of which 3000 was pilot-in-command (PIC), 2300 of which was in the CL-65, and 1000 of which was CL-65 PIC. His prior commercial flight experience was on the BE-1900D and C-182. He flew the BE-1900D at Great Lakes Airlines as First Officer and Captain.

The first officer, age 39, was hired by Air Wisconsin on July 22, 2007. He held an Airline Transport Pilot certificate single-engine land, a commercial pilot certificate multi-engine land with instrument-airplane rating, and is a certified flight instructor, instrument, single and multi-engine land. He holds advanced and instrument ground instructor certificates with an FAA "gold seal". He has a type rating in the CL-65. He held an FAA first class medical, dated December 7, 2007 with limitations.

He had a total flying time of 2000 hours, of which 1400 was single engine, 600 multi engine, and 150 hours of turbine time, all of which was on the CL-65 at Air Wisconsin. He had worked for two years as a Certified Flight Instructor (CFI), most recently for one year at Frederick, MD, and the year before that at Chesapeake, VA. Prior to that he managed a flight school at Frederick. He had an earlier career in accounting and consulting, held a degree in accounting and was a Certified Public Accountant.

AIRCRAFT INFORMATION:

N470ZW, a CL-600-2B19, serial number 7927, was about 3 ½ years old. Air Wisconsin acquired the airplane new. The airplane was equipped with General Electric CF34-3B1 engines. Air Wisconsin dispatch records indicate that the airplane was loaded within appropriate weight and balance criteria. Estimated landing weight was 45,052 pounds. Post-accident examination of the flight deck revealed that the anti-skid system was armed, spoilers retracted, thrust reversers armed, and flaps at 45 degrees. The speed card page for a 45,000 pound landing weight was open, which showed a Vref speed of 138 knots. There were no relevant open maintenance items in the aircraft logs. One MEL item "APU inlet door inhibited open" resulted in a speed limitation of 300 knots IAS. Flight recorder circuit breakers were found pulled.

METEOROLOGICAL INFORMATION:

The current observation at the time of the accident was reported at 2106 UTC, and indicated wind from 010 degrees at 8 knots, visibility one and three quarter miles in rain and mist, ceiling 300 feet overcast, temperature three degrees Celsius, dewpoint 2 degrees Celsius, altimeter setting 29.06 inches of mercury. Remarks indicated that drizzle changed to rain at 2058. Just after the accident weather was reported as wind 050 at three knots, visibility one and one half miles in mist, three hundred feet overcast, temperature three degrees Celsius, dewpoint two degrees Celsius, altimeter setting 28.96 inches of mercury. Remarks indicated that rain ended at 2139 and pressure was falling rapidly.

An arriving A319 ahead of the accident airplane reported that they broke out of the clouds at 300 feet. ATC reported that many arrivals reported tailwinds on the approach, which diminished at about 1000 feet.

ATC reported that at two occasions about one hour prior to the accident a readable RVR value was produced, due to an arriving airplane disturbing snow alongside the runway causing the local visibility to drop. They momentarily indicated a value of 6000 RVR and then, when the disturbed snow settled, returned to the prevailing visibility. There was no temporary obscuration at the time of the accident airplane’s landing.

AIDS TO NAVIGATION:

The instrument landing system (ILS) runway 5 at PVD provides standard straight-in arrival minima of 200 feet decision height, with ½ mile visibility (lower CAT II and CAT III minima are available to appropriately equipped and crewed aircraft). The localizer component is aligned to 047 degrees magnetic, the glideslope is 3 degrees. An ALSF2, standard 2,400 foot high intensity approach lighting system with centerline sequenced flashers was installed. On Tuesday, December 18, 2007, the FAA performed a flight inspection of the facility and all parameters were found within normal tolerances.

COMMUNICATIONS:

No communications problems were noted at any time during the accident sequence.

AERODROME INFORMATION:

The Theodore Francis Green State Airport is located approximately 6 miles south of the city of Providence, Rhode Island. The airport averages about 300 operations per day, with about two thirds of the operations comprised of major and regional air carriers. Runway 5 is 7,166 feet long by 150 feet wide and constructed of grooved asphalt. Touchdown zone elevation is 51 feet msl. The runway is marked for precision instrument operations, has in-pavement centerline and touchdown zone lighting, and is equipped with a standard high intensity approach lighting system with centerline sequenced flashing lights. The runway is unobstructed.

A field condition report at 1506 EST indicated that runway 5 was "wet with a few scattered thin patches of slush." General taxiway condition was recorded as "wet with scattered patches of packed snow/slush/ice up to 1 inch." This runway condition had been consistently reported since 1047 EST. The last treatment of the runway occurred at that time, and friction measurements were 45/49/43 mu. According to airport management after that time, the weather event had ended, the runway was wet and all pilot reports of braking action were "good." At the time of the accident the runway was reported as wet with no contamination. An Airbus 319 which arrived four minutes prior to the accident airplane reported braking action was good.

FLIGHT RECORDERS:

The Digital Flight Data Recorder was an L-3 Communications FA2100 Serial number 260909. The recorder was in good condition and the data were extracted normally. Details of the recorder and plots of selected parameters are in the NTSB public docket. FDR information was used as the basis of the performance studies and other sections of the report.

The Cockpit Voice Recorder was an L-3 Communications FA2100-1010, Serial Number 226552. The recorder was in good condition and the data were extracted normally. A CVR group was convened at NTSB headquarters and produced a transcript, which appears in the NTSB public docket.

WRECKAGE AND IMPACT INFORMATION:

The first piece of aircraft debris was located approximately 1000 feet from the arrival threshold. Two main gear pivot (pintle pin) bushings and a bracket were located on the runway. Additional pieces of fiberglass aircraft parts consistent with the main gear door were found nearby broken runway edge lights at approximately 2500 feet from the threshold. Ground tracks indicated all three landing gear were off the runway at approximately 3200 feet from the threshold, and the airplane came to rest about 300 feet left of the runway in a grass and snow covered area about 3,700 feet from the threshold, oriented on a bearing of about 320 degrees magnetic.

The flight crew performed a shutdown checklist and secured the airplane. Airport management emergency personnel responding to the accident ensured that the circuit breakers for the flight recorders were pulled.

MEDICAL AND PATHOLOGICAL INFORMATION:

Toxicological samples provided by the flight crew to representatives of Air Wisconsin Air Lines tested negative.

FIRE

None.

SURVIVAL ASPECTS:

The 3 crew members and 31 passengers were not injured, and exited the airplane via the normal airstair door. Both pilots reported that the Captain called the Flight Attendant on the interphone and asked him if there was any fire or any injuries, and that he then used the PA to say "remain seated" and "you can see what happened." However, the Flight Attendant said he did not know that they had had an accident until after he opened the door and saw damage to the airplane. The pilots ran the Immediate Action Checklist for Evacuation and shut the engines down but left the APU running. The Captain said once he was satisfied that there was no fire, his concern was keeping lights and heat to calm the passengers. He reported that Airport Rescue and Fire Fighting personnel arrived quickly, were positioned by the doors, and assisted in an orderly evacuation.

TESTS AND RESEARCH:

Results of the metallurgical testing of the left main landing gear mounting trunnion revealed no abnormal findings in visual inspections both by naked eye and under a stereoscopic microscope. No evidence of fatigue marks was noted along the fracture surfaces. Gross 45-degree shear lips were apparent throughout the primary fracture and in secondary cracks. Shear lips of this nature are typically associated with a static failure of ductile material

Electrical conductivity readings indicated the trunnion was in a sound/uniform thermal condition (i.e., devoid of segregation and/or soft spots) and the part appeared to be free of undue wear zones, arcing strikes, corrosion damage by-products and similar service defects.

The tensile properties in the trunnion were within the specified limits and no evidence of subsurface or surface defects was found which might have contributed to crack initiation.

A 2" long segment cut from the diagonal fracture in the trunnion was subject to Scanning Electron Microscope examination. Evidence of elongated dimples was apparent throughout the specimen, which are normally associated with shear failure mode in a ductile member under static load. No evidence of fatigue striations was noted on the specimen.

The materials examination concluded that the fracture in the trunnion was the result of an abnormal static loading; as would be associated with a hard landing. The trunnion functioned as designed and released the landing gear when the loads exceeded the design limits.

The left main landing gear was removed and examined at the manufacturer’s facility. External visual inspection revealed no obvious signs of major damage to the gear. The cross pin holding the trunnion pin in place in the assembly could be removed with ease and rotated freely. The trunnion pin however was jammed in the housing. After removal the pin was measured to be 0.016" bent. Typical wear marks were observed on the trunnion pin. The main fitting trunnion bore was also bent, in the same direction.

The shock strut assembly, gear outer cylinder, and landing gear axle indicated no abnormalities, and dimensional checks were within tolerances.

Under the supervision of an NTSB Vehicle Performance Specialist, Bombardier Flight Sciences used a flight-test validated Level D Aerodynamic

NTSB Probable Cause

the captain’s attempt to salvage the landing from an instrument approach which exceeded stabilized approach criteria, resulting in a high sink rate, likely stall, and hard landing which exceeded the structural limitations of the airplane.

Contributing to the accident was the first officer’s poor execution of the instrument approach, and the lack of effective intra-cockpit communication between the crew. Additional contributing factors to the accident are the lack of effective oversight by AWAC and the FAA to ensure adequate training and an adequate experience level of first officers for line operations.