Qatar Airways plane avoids mid-air collision, but many questions unanswered

A newly acquired Airbus A350-1000 series aircraft operated by Qatar Airways had a close call over Iran on April 12 when it came into close proximity to another aircraft. The airliner, equipped with state-of-the-art technology and Traffic Collision Avoidance System (TCAS), was seen climbing by about 500 feet while cruising at 34,000 feet on a flight from Doha, Qatar to Los Angeles, US.

Flightradar24-plotted aircraft track. Source: Flightradar24/Youtube/Captain Amit Singh

The automated TCAS detects an incoming aircraft. When the intruder crosses a pre-set threshold, the system automatically initiates an avoidance manoeuvre to provide a minimum safe distance of separation between the two aircraft.

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In this incident, the Qatar Airways A350, carrying a registration code of A7-ANO, dropped its speed by almost 35 kmph while cruising at 888 kmph. This drop in speed at a high altitude is not safe since the avoidance manoeuvre climb is not supposed to be a rough one but as smooth a climb as is carried out during a normal day-to-day flight as the engines are capable of developing sufficient thrust to maintain the speed.

The possible reasons could be a sudden order to 'Climb' due to a malfunction in the intruder aircraft's altitude hold capability. In this event, the A350 aircraft's autopilot would increase the load manoeuvre capability by 0.3g and pull up the nose of the aircraft. The engines are expected to increase the thrust simultaneously to prevent a large speed decay and a potential stall. 

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It needs to be investigated if the aircraft performed the evasive manoeuvre as per the design requirements or was there insufficient engine thrust to back the automatic manoeuvre. Human factors could also play a part in this event.

(This article first appeared in avobanter.com)