On 11 May 2011, a Bombardier DHC8-400 aircraft being operated by Porter AL on a scheduled passenger flight Toronto City to Ottawa and another aircraft of the same type and operator on a scheduled passenger flight from Montreal to Toronto City came into close proximity south east of the airport and received and actioned co-ordinated TCAS RAs. Minimum separation was 300 feet vertically at the same altitude. There were no abrupt manoeuvres and none of the occupants were injured.