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  • DH8A/DH8C, en-route, northern Canada, 2011 (Synopsis: On 7 February 2011 two Air Inuit DHC8s came into head-to-head conflict en route over the eastern shoreline of Hudson Bay in non radar Class ‘A airspace when one of them deviated from its cleared level towards the other which had been assigned the level 1000 feet below. The subsequent investigation found that an inappropriate FD mode had been used to maintain the assigned level of the deviating aircraft and noted deficiencies at the Operator in both TCAS pilot training and aircraft defect reporting as well as a variation in altitude alerting systems fitted to aircraft in the DHC8 fleet.)
  • A320/B738, vicinity Delhi India, 2013 (Synopsis: On 2 September 2013, a B737 crew were not instructed to go around from their approach by ATC as it became increasingly obvious that an A320 departing the same runway would not be airborne in time for a landing clearance to be issued. They initiated a go around over the threshold and then twice came into conflict with the A320 as both climbed on similar tracks without ATC de-confliction, initially below the height where TCAS RAs are functional. Investigation attributed the conflict to ATC but the failure to effectively deal with the consequences jointly to ATC and both aircraft crews.)
  • A320 / B738, en-route, near Córdoba Spain, 2014 (Synopsis: On 30 October 2014, a descending Airbus A320 came close to a Boeing 737-800 at around FL 220 after the A320 crew significantly exceeded a previously-instructed 2,000 fpm maximum rate of descent assuming it no longer applied when not reiterated during re-clearance to a lower altitude. Their response to a TCAS RA requiring descent at not above 1,000 fpm was to further increase it from 3,200 fpm. Lack of notification delayed the start of an independent Investigation but it eventually found that although the A320 TCAS equipment had been serviceable, its crew denied failing to correctly follow their initial RA.)
  • GLF5 / A319, south-eastern France, 2004 (Synopsis: On 16 September 2004, a loss of separation occurred over Geneva between Air France A319 and a Gulfstream 5 which commenced descent without clearance by ATC and with coordinated TCAS RAs not followed by either aircraft.)
  • DH8D / DH8D, vicinity Sudbury ON Canada, 2016 (Synopsis: On 14 October 2016, two Bombardier DHC8-400s received coordinated TCAS RAs as they came into opposite direction conflict near Sudbury, an uncontrolled airport, as one was descending inbound and emerging from an overcast layer and the other was level just below that layer after departing. Both aircraft crews ignored their RAs and their respective visual manoeuvring brought them to within 0.4nm at the same altitude. The Investigation noted that the conflict had occurred in Class ‘E’ airspace after the departing aircraft had cancelled IFR to avoid a departure delay attributable to the inbound IFR aircraft.)