On 27 October 2011, a Northern Thunderbird Air Ltd. Beechcraft King Air 100 (registration C‑GXRX) departed Vancouver International Airport (YVR) with seven passengers and two pilots, bound for Kelowna International Airport (YLW).
About 15 minutes after take-off, the flight diverted back to Vancouver because of an oil leak. No emergency was declared. At 1611 Pacific Daylight Saving time, approximately 300 feet above ground and 0.4 miles from the runway, the aircraft suddenly banked left and pitched nose-down. It then collided with the ground, and caught fire before coming to rest on an arterial roadway just outside the YVR perimeter.
Passersby helped evacuate some passengers and fire and rescue personnel rescued the remaining passenger and the pilots. The aircraft was destroyed and all of the passengers were seriously injured. Both pilots succumbed to their injuries in hospital.
Investigation Team Work
The investigation team is led by a Transportation Safety Board of Canada (TSB) Investigator-in-Charge, Bill Yearwood. Mr. Yearwood has 41 years of aviation experience; 18 years as a commercial pilot in the civil aviation industry, and 20 years in aviation safety. He has been an aircraft accident investigator for the past 13 years. Mr. Yearwood is assisted in this investigation by experts in flight operations, aircraft performance, aircraft systems, aircraft engines, human performance, air traffic control (ATC).
While these experts come from within the TSB, assistance has also been provided by: Northern Thunderbird Air, NAV CANADA, the RCMP, BC Coroners Service, Beechcraft, Raisbeck Engineering, Pratt and Whitney Canada, the Vancouver Airport Authority, and fire and rescue experts. These experts assist the team uncover and understand all of the underlying factors which may have contributed to the accident.
Each investigation consists of three phases: Phase 1 is the Field Phase when accident information is gathered from a number of sources including the accident site; the team continues its work in Phase 2 which is the Post-Field Phase where information is gathered and analysis begins. The final phase is the Report Production Phase. This phase is intended to ensure procedural fairness and the accuracy of the Board's final report. The Board considers all representations (comments) and will amend the report if required. Once the Board approves the final report, it is prepared for release to the public.
This investigation has now entered Phase 2. While continuing to accumulate the information it needs, the team has now begun the work of analyzing the considerable amount of data in order to determine what happened, why it happened and, what can be learned to help ensure it does not happen again.
Work Completed to Date
Progress has been made in a number of areas. The accident site has been extensively photographed and documented and the TSB has removed the wreckage for further analysis.
The flight recorders were located on the first day and delivered to the TSB lab for data download and analysis. The recorders contain much needed data and will assist investigators in the understanding of what happened during the approach phase of the flight.
Interviews have been conducted; documents have been collected; and electronic information has been downloaded. The analysis of this material has begun but a large amount of work remains.
What We Know
The flight was returning to YVR because oil was leaking from the left engine. The left engine did not lose power and the crew did not declare an emergency.
The weather in the Vancouver area was mostly clear with light and variable winds. While the flight departed on an instrument flight plan, weather conditions allowed the crew to conduct a visual approach to YVR runway 26 left.
The approach to the runway at YVR was normal until the last moments before the anticipated touch down. The aircraft slowed below its target approach speed and seconds later, the aircraft banked left (about 80⁰), and pitched nose-down (about 50⁰). The captain was able to level the wings and pull the nose up slightly before impact with a paved road.
The road is a heavily travelled arterial with six lanes at that location. An oncoming car swerved across a median to avoid a major collision with the aircraft, but was clipped by the aircraft’s wing tip. The accident happened at a time when the traffic lights provided a gap in the flow. Several of the people who helped rescue the passengers were stopped at the traffic light at the time of the accident.
After colliding with the ground, the landing gear collapsed, the aircraft skidded along the road on its belly, shed parts, and spilled fuel. A post-impact fire erupted. After the aircraft stopped, the passenger seated closest to the main door tried to open it. After repeated attempts, the door opened. That passenger and persons in the area helped all but one passenger out of the burning wreck. The cockpit was farthest away from the door, and initial rescuers were not aware of the total number of persons on board. By the time six of the passengers were out of the wreck, the heat, smoke and fire prevented the initial rescuers from reaching the seventh passenger who was near the front of the aircraft.
Richmond Fire-Rescue personnel arrived approximately three minutes after the crash, from a fire hall about 0.5 miles from the accident site. They rescued the seventh passenger; however there was some confusion as to the total number of persons on board and how many pilots there were. Fire and rescue personnel worked to rescue the pilots while the fire was being doused. The aircraft was across a ditch just outside the YVR perimeter fence. A YVR fire truck arrived about four minutes after the crash, having been dispatched by ATC, and was able to spray the wreckage from the airport side of the fence. Another fire truck crashed through the airport perimeter fence gate to get to the accident site. Joint fire and rescue personnel extinguished the fire, cut the wreckage and rescued the pilots.
Fire and rescue personnel reported that the aircraft’s electrical wiring arced continuously and there was concern for personnel entering the wreckage even after the fire was extinguished.
The fire started immediately after impact, and, while it was apparent spilled fuel ignited as the aircraft was skidding across the road, after the aircraft and engines stopped, fire concentrated on the right wing.
The King Air has only one cabin door, located at the left rear and one emergency exit window located over the right wing, which leads persons onto the wing over the battery compartment. For the flight, the cabin was configured with eight passenger seats, all facing forward in rows with a centre aisle. This diagram shows the cabin configuration and exits. There was fire visible outside on the right, making the door the only viable exit. The door frame was deformed and the door was jammed shut. An able passenger opened it with difficulty. Most of the other passengers and both pilots were disabled by impact injuries.
While all the persons onboard sustained serious bone fractures from the impact deceleration forces, those injuries were survivable. The post-impact fire compromised that survivability. Both pilots suffered burns as a result of the post-impact-fire and later died as a consequence.
Investigation Activities in Progress
The TSB is proceeding along several avenues of investigation concurrently, in order to understand why the aircraft slowed and crashed 0.4 miles from the runway. To that end, investigators, assisted by specialists in aerodynamics and human performance are reviewing factors that may have contributed to this tragic accident.
The TSB has classified this occurrence as a loss of control accident. However, other areas being investigated are:
- Aircraft design to reduce the risk of post-impact fires; and
- Unpublished critical control speeds.
Communication of Safety Deficiencies
Should the investigation team uncover a safety deficiency that represents an immediate risk to aviation, the Board will communicate without delay so it may be addressed quickly and the aviation system made safer.
Outstanding TSB Recommendations – Post-impact Fires
A 2006 TSB safety study of post-impact fires identified 128 of 521 occurrences in which fire or smoke inhalation contributed to the cause of death or serious injuries. Most of the accidents were otherwise survivable. Six years ago, the Board made three recommendations designed to lessen the risk of fatal post-impact fires.
Recommendation A06-10 states:
To reduce the number of post-impact fires in impact-survivable accidents involving existing production aircraft weighing less than 5700 kg, Transport Canada, the Federal Aviation Administration, and other foreign regulators conduct risk assessments to determine the feasibility of retrofitting aircraft with the following:
- selected technology to eliminate hot items as a potential ignition source;
- technology designed to inert the battery and electrical systems at impact to eliminate high-temperature electrical arcing as a potential ignition source;
- protective or sacrificial insulating materials in locations that are vulnerable to friction heating and sparking during accidents to eliminate friction sparking as a potential ignition source; and
- selected fuel system crashworthiness components that retain fuel. (SII A05-01)
Recommendation A06-09 states:
To reduce the number of post-impact fires in impact-survivable accidents involving new production aeroplanes weight less than 5700 kg, Transport Canada, the Federal Aviation Administration, and other foreign regulators include in new aeroplane type design standards:
- methods to reduce the risk of hot items becoming ignition sources;
- technology designed to inert the battery and electrical systems at impact to eliminate high-temperature electrical arcing as a potential ignition source;
- requirements for protective or sacrificial insulating materials in locations that are vulnerable to friction heating and sparking during accidents to eliminate friction sparking as a potential ignition source;
- requirements for fuel system crashworthiness;
- requirements for fuel tanks to be located as far as possible from the occupied areas of the aircraft and for fuel lines to be routed outside the occupied areas of the aircraft to increase the distance between the occupants and the fuel; and
- improved standards for exits, restraint systems, and seats to enhance survivability and opportunities for occupant escape. (SII A05-01)
Recommendation A06-08 states:
Transport Canada, together with the Federal Aviation Administration and other foreign regulators, revise the cost-benefit analysis for Notice of Proposed Rule Making 85-7A using Canadian post-impact fire statistics and current value of statistical life rates, and with consideration to the newest advances in post-impact fire prevention technology. (SII A05-01)
The responses from regulators on these recommendations are Unsatisfactory. The Transportation Safety Board of Canada is concerned that the world’s regulators have largely ignored these recommendations. In the meantime, the Board continues to investigate aviation accidents like the Northern Thunderbird Air accident where some or all onboard survive the crash only to die as a consequence of post-impact fires.
The Families
The TSB investigation team knows that the survivors and the families who lost loved ones want answers. As we continue our work, our hope is that we will be able to answer: What happened? Why did it happen? What can we learn so that it does not happen again? We look for these answers to make a safer transportation system for all Canadians.
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