The Directorate General of Civil Aviation (DGCA) has found serious lapses on the part of air traffic controllers in Delhi while investigating a case of a near miss between IndiGo and KLM flights over the airspace in the national capital in 2016. An IndiGo flight from Delhi to Bengaluru and KLM Royal Dutch Amsterdam-Kuala Lumpur flight came close to each other over Delhi airspace on November 2, 2016.According to the report submitted by the aviation regulator to the civil aviation ministry, 101 of the 109 radar controllers at Delhi air traffic control did not perform any duty for about a year. “In this serious incident, while deciphering the ATC log books for tower unit, it was found that 101 radar controllers, out of total 109 radar controllers as on date of serious incident, were found to have not performed any duty in tower unit (for over six months) during a period of one year (I.e. from 01/01/2016 to 31/12/2016) thereby rendering their tower rating as invalid,” the report points out.They also used wrong call sign to guide the aircraft due to which the distance between the two planes was reduced to 3.6 nautical miles (lateral) and 200 feet (vertical), forcing their pilots to issue collision warning. According to the DGCA, ATC is not following the proper handing over procedure.“The probable cause of the incident was assigning wrong or same flight level to both the flights and use of wrong call sign continuously,” a DGCA officer said.The DGCA has recommended to the Airports Authority of India to give corrective training to radar controllers.“Necessary steps be taken for revalidation of tower rating of 101 radar controllers and AAI shall take measures to prevent such lapses at mass level in future,” DGCA in its report said.