Near Miss Between Cessna Citation 650 and Boeing 767 at Montreal

Incident Overview and Aircraft Details On an instrument flight rules flight, a Skyservice Cessna Citation 650, registration C-FJJC, was inbound to Montreal International Airport, Dorval, Quebec, from Toluca, Mexico. The aircraft was in descent to 6,000 feet. Simultaneously, Air Canada flight 411, a Boeing 767, registration C-GAUP, had departed runway 28 at Dorval en route to Toronto via Ottawa. The Boeing 767 was climbing straight ahead on an instrument flight rules flight plan. The two aircraft passed with 1,400 feet of vertical spacing and approximately 0.25 mile of horizontal spacing. The Boeing 767 pilot stopped the climb at 5,200 feet after a traffic alert and collision avoidance system (TCAS) traffic advisory indicated the Citation directly ahead. The Citation was not equipped with TCAS, and its pilot did not see the Boeing 767 while under instrument meteorological conditions. ## Controller Actions and Radar Display The Boeing 767 was controlled by the Montreal Area Control Centre (ACC) departure controller, while the Citation was controlled by the terminal south sector controller. At 1212:35 eastern daylight time, the departure controller radar-identified the Boeing 767 and cleared it to maintain 17,000 feet. At 1212:34, the terminal south controller advised the Citation pilot of traffic at the one o'clock position, assuming the Boeing 767 would level off at 5,000 feet per terminal procedures. At 1213:16, the Boeing 767 pilot reported traffic at 5,200 feet. The departure controller then cleared the Boeing 767 to maintain 5,000 feet and turn left to a heading of 260 degrees. Radar data processing system (RDPS) displays showed full data blocks for aircraft under the departure controller's jurisdiction, marked with the controller jurisdiction symbol (CJS) “DP.” Other targets, including the Citation, displayed limited data blocks with the CJS “TS.” The Citation’s radar target was partially obscured by the data block of a visual flight rules aircraft, C-FHTA, from 1212:05 to 1212:35, during which time the departure controller began issuing the climb clearance. ## Findings and Contributing Factors The TSB determined that the departure controller issued the climb clearance through airspace assigned to another controller without coordination, which was permitted by Montreal ACC terminal operational procedures. The controller did not recall the presence of the inbound Citation when issuing the clearance and did not monitor the climb with sufficient attention to detect the conflict. The terminal south controller took no action to ensure separation, assuming the departure controller would follow standard procedures and level the Boeing 767 at 5,000 feet. The TSB noted that the ad hoc procedure used to expedite the departure lacked defences against normal human error, such as forgetfulness and loss of situational awareness. The departure controller was fully qualified and experienced, with no indication of sleep debt or fatigue. The partial obscurity of the Citation’s radar target and the provision of traffic information to other visual flight rules aircraft did not appear to unduly distract the controller. ## Safety Recommendations and Follow-up In August 2000, the TSB forwarded an Aviation Safety Advisory (No. A000035) to NAV CANADA highlighting the risks of using ad hoc control practices or altering assigned airspace responsibilities. NAV CANADA subsequently issued Air Traffic Services Safety Bulletin No. 2000-3, effective October 26, 2000, titled SQUAWK 7700, which addressed the risks of deviating from established procedures and the importance of mitigating increased risks. The bulletin was designated as a mandatory briefing item. The Montreal Area Control Centre also initiated a review of procedures used in coordination and interaction between the departure and arrival sectors.