The regulator had recommended inspection of the locking mechanism to ensure the fuel switches don’t accidentally move from ‘run’ to ‘cut off’ position.Pushkaraj Sabharwal, father of Capt Sumeet Sabharwal who died in the accident, has sought a formal investigation. He criticised the preliminary report, calling it “deficient, diversionary, and discrepant” for insinuating the fault lies with pilots while giving a clean chit to Boeing.