The Bengal government ordered a probe after chief minister Mamata Banerjee hurt her back while the aircraft she was travelling on experienced a sudden drop in altitude before landing in Calcutta on Friday

Mamata was returning from Varanasi where she had gone to campaign for the Samajwadi Party for the on-going Uttar Pradesh Assembly polls.

According to Trinamul sources, although the weather over Calcutta was clear, the altitude graph of the aircraft showed an unusual drop, caused by a sudden drop in air pressure. This was preceded by a sudden jerk in which Mamata was hurt. The Bengal chief minister has had history of trouble while travelling by air.

In November 2016, a private airline she was on while returning from Patna had hovered over Calcutta skies for over half an hour before landing at the Netaji Subhas Chandra Bose International airport. The Trinamul had then alleged a "conspiracy to assassinate" the party chief since the flight was allowed to hover while running low on fuel.

In August 2017, an Air India aircraft in which the chief minister was scheduled to return to Calcutta from Delhi was delayed by nearly four hours as one of its cooling units had failed and the airline was trying to arrange for an alternate flight.

In February 2018, while on her way back to Calcutta after a tour of North Bengal, the flight from Bagdogra had hovered for around 30 minutes as no runway were free. An irate Mamata had questioned the Director General of Civil Aviation why the aircraft in which she was traveling was not given priority to land.