Accident Overview
At about 1600 Pacific Standard Time in daylight conditions, four light aircraft departed Langley Regional Airport in Langley, British Columbia, for a local formation flight to Chilliwack, British Columbia. Around 1615, during a turn, a Cessna 150G (registration C-FVXY, serial number 15066711) and a Cessna 150L (registration C-GZUB, serial number 15074143) collided. The two aircraft briefly descended joined together and out of control, but at about 400 feet above ground level, they separated. C-FVXY broke up in flight and fell into a shallow slough; the two occupants were fatally injured, and the aircraft was destroyed. The pilot of C-GZUB regained control and landed in a farm field without injury; however, the aircraft was substantially damaged. No fire occurred, and the emergency locator transmitter on C-FVXY activated upon impact.
Investigation Findings
The Transportation Safety Board of Canada determined that both pilots were intentionally flying in close proximity as part of a pre-arranged formation flight. The flight profiles indicated that neither pilot saw the other aircraft in sufficient time to take effective evasive action. No evidence of pre-existing mechanical defects was found in either aircraft. The investigation focused on operational issues and hazards of formation flight, including vision limitations of high-wing aircraft and the flight path.
The high-wing Cessna 150 has known vision restrictions due to pilot seat position and cockpit dimensions. During turns, the wings restrict upward fields of view to the sides. Formation flying in high-wing aircraft is regarded as more challenging and introduces greater collision risk than in low-wing aircraft. When high-wing and low-wing aircraft fly together, the risk of losing sight or collision can be higher. The restricted cockpit vision from the left pilot seat of C-GZUB prevented the pilot from seeing the other aircraft: first, unable to locate the leader before turning back, and second, unable to see the leader in time during the turn to prevent collision. It is possible that the crew in C-FVXY also had their vision blocked.
Using flight data, impact damage signatures, and laboratory calculations, the investigation determined a likely collision flight path. All possible scenarios involved a loss of sight influenced by window and wing configuration. When the leader (C-FVXY) turned right, the wingman (C-GZUB) had to reduce airspeed and height to maintain formation station. If the wingman did not reduce power sufficiently or quickly enough, the aircraft would move forward and out of the arc of available vision under the left wing.
Causes and Contributing Factors
The investigation identified the following causes and contributing factors:
- During the right-hand turn in formation flight, the pilot of C-GZUB lost sight of the leader (C-FVXY).
- After initially adopting a flight path that effectively eliminated the risk of collision, the pilot of C-GZUB turned back toward the leader to rejoin the formation, unintentionally placing the aircraft on a collision course.
- The high-wing configuration of C-GZUB significantly restricted the field of vision, and during the left-hand turn, the pilot was unable to see the lead aircraft on a collision course.
- The impact damage from the in-flight collision rendered C-FVXY uncontrollable; it descended rapidly and collided with terrain.
- The pre-flight briefing did not discuss contingency procedures for loss of sight or accepted practices for returning to formation.
- For the occupants of C-FVXY, forces from the in-flight impact and ground collision exceeded normal human tolerance, making the accident unsurvivable.
Risk Findings
The investigation noted that formation flying involving high-wing aircraft poses elevated risk due to limited cockpit vision angles. Flying dissimilar aircraft types, particularly combining high-wing and low-wing aircraft, demands higher skill levels and creates greater risk for casual formation flyers. Formation flying requires higher skill, discipline, and training than conventional flying; without appropriate formal training, the risk of in-flight collision increases. The ELT on C-FVXY transmitted only on 121.5 MHz, and its signal was only received by high-flying aircraft in the local area, posing a risk that the emergency would not be detected. Not having a qualified observer on initial formation flights increases the risk of inappropriate pilot actions during loss-of-sight events.
Safety Actions
Transport Canada issued a safety bulletin on formation flying hazards and distributed a "Take Five" brochure titled "Formation Flight" (TP 2228E-39) at the Canadian Owners and Pilots Association convention in June 2011. The brochure highlights the importance of pre-flight planning and flying skills in reducing risks associated with formation flying.
The report was officially released on September 11, 2012.