An awkwardly fitted cap of the gearbox of industrialist Anil Ambani's helicopter is what led maintenance technician Bharat Borge to detect pebbles inside, says the FIR lodged in the case with Airport police station.

"According to the FIR, Bharat Borge first saw an awkwardly positioned cap after which he informed Sudhakar Surve, an administrative officer at Air Works," police said. Surve then approached police and lodged a complaint.