A mid-air collision between an Air Arabia flight and a Qatar Airways, which could have killed hundreds of passengers, was averted on Wednesday.
The two flights were passing through the city early on Wednesday morning when the incident occurred.
One of the planes had allegedly strayed from its dedicated flight path.
A preliminary report, submitted by the city air traffic control (ATC) office to the aviation regulation, said that one of the planes had breached the minimum vertical distance of 1,000 feet - supposed to be maintained between two airborne aircrafts - by straying from its flight path.
The Directorate General of Civic Aviation (DGCA) is now investigating the cause of the incident. The Air Arabia flight was traveling from Calicut to Sharjah and the Qatar Airways flight was heading to Calicut from Doha, at a higher altitude.
Sources in the ATC said that one of the two aircrafts moved upward or downward by 100 feet, breaching the vertical safety distance to be maintained. It is not yet known which of the two planes was responsible for the breach.
A warning from the Traffic Collision Avoidance System (TCAS), an in-built device in planes to avoid mid-air collisions, averted the accident.
Although preliminary reports indicate a breach of just 100 feet, the nature of the alert from the TCAS suggests that the distance between the two planes could have been less.
The TCAS issues two kinds of alerts - the traffic advisory (TA), which is the first level of alert and the resolution advisory (RA), which is a more serious alert, a final call to pilots to maneuver the plane and avoid a crash.
For Wednesday's incident, an RA had been issued.
A spokesperson of Air Arabia did not comment specifically on the incident, but the airline issued a general statement which read: "Air Arabia assures that all its aircraft are equipped with the latest weather radar systems and TCAS 7 systems… Air Arabia crew follow standard operating procedure at all times to ensure the safety of passenger, crew and aircraft."
Qatar Airways spokesperson did not respond to queries sent through email.