Why did IndiGo flight return to Mumbai after extra passenger found standing? Explained

livemint.com:

passenger boarding process of 6E 6543 from Mumbai to Varanasi, wherein a standby passenger was allotted a seat reserved for a confirmed passenger. The error was noticed before the departure of the aircraft, and the standby passenger was deboarded. This led to a slight delay in the departure of the aircraft.

IndiGo will take all measures to strengthen its operational processes and regrets the inconvenience caused to customers," an airline spokesperson said. Overbooking is a very common phenomenon in aviation, and especially during peak travel season, a lot of flights go overbooked. The practice is a revenue-generating avenue for airlines as all those who overbook don't turn up to board the flight.

In such situations, there are rules for the stand-by passengers who will be allowed to board the flight if the passenger doesn't turn up within the stipulated period. In the recent case with IndiGo, a stand by passenger was allowed to board the flight when the actual passenger didn't show up at the check-in counter. In all probability, the actual passenger directly turned up at the boarding gate as he just had hand baggage and boarded the flight.

The stand by passengers was asked to leave his seat after the actual passenger turned up but he merely went to the galley. The aircraft was taxied out to the runway without anybody noticing the extra passenger, who had entered the aircraft legally. After he/she was noticed, the aircraft returned to the bay and took off again after deboarding the extra passenger and completing all necessary protocols.