The aviation safety regulator has begun a probe into a mid-air safety scare wherein a private jet strayed from the altitude allotted to it and came close to a Saudi Airlines flight from Hyderabad to Jeddah. The incident took place in the Pune airspace on May 15. According to preliminary investigations by the directorate general of civil aviation (DGCA), the crew operating the private jet encountered a traffic collision avoidance system (TCAS) alert. The private belonged to GVK, the leading stakeholder in the consortium that runs the Mumbai airport. The TCAS, which warns pilots about the presence of another aircraft, issues two kinds of warnings — traffic advisory (TA) and resolution advisory (RA). The first warning indicates an aircraft at a vertical distance of 35 to 40 seconds. In this case, the system issued an RA warning, which means the jet was only 25 to 30 seconds away from the Saudi flight. “The incident has been reported to DGCA. The probe may begin by Monday,” said a senior ATC official.