News release

June 2013 mid-air collision near Pemberton, British Columbia, highlights risk of relying solely on the see-and-avoid principle for collision avoidance

Richmond, British Columbia, 18 September 2014 – In its investigation report (A13P0127) released today, the Transportation Safety Board of Canada (TSB) determined that a fatal mid-air collision between a Cessna 150 and a powered glider near Pemberton, British Columbia, was caused by the failure of the see-and-avoid principle as the sole means of collision avoidance.

On 29 June 2013, a Cessna 150 was flying from Lillooet to Nanaimo, British Columbia, with 1 pilot and 1 passenger aboard along a preferred air route over the Pemberton area. Meanwhile, a Stemme S10-VT motor glider on a local sightseeing flight was inbound to the Pemberton airport with 1 pilot and 1 passenger aboard. Both aircraft were flying in accordance with visual flight rules (VFR). The two aircraft collided west of Pemberton at 1218 Pacific Daylight Time. Both aircraft were destroyed and there were no survivors.

The investigation found that the weather was clear and the winds were calm in the area at the time of the occurrence. The converging tracks of the two aircraft caused blind spots for the pilots. This factor, coupled with human vision limitations offered reduced opportunities for the pilots to avoid the collision. During the collision, the right wings of both aircraft were shorn off in mid-air rendering the aircraft uncontrollable, and the collision with terrain that ensued was unsurvivable.

If the see-and-avoid principle is relied upon as the sole means of collision avoidance when flying under VFR, there is a continued risk of collision. The TSB has investigated numerous occurrences (most recently A12H0001) where reliance on the see-and-avoid principle resulted in a mid-air collision. The investigation report mentions numerous technologies (link to Appendix B of report) that can assist pilots with collision avoidance.


The TSB is an independent agency that investigates marine, pipeline, railway and aviation transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.

For more information, contact:
Transportation Safety Board of Canada
Media Relations
Telephone: 819-994-8053
Email: media@tsb.gc.ca