New Delhi, April 2 (IANS): A total of 52 Vistara flights were cancelled on Tuesday after pilots remained on mass sick leave in protest against the terms of a new contract following the airline's decision to merge with Air India.

Sources told IANS that Vistara pilots collectively requested for sick leave over the introduction of a revised salary structure by the airline, which is seen as a prelude to its merger with Air India.

Under the terms of the new contract, which came into effect in April, Vistara pilots will now be paid a fixed salary for 40 hours instead of the previous 70 hours.

This change is in line with a standardised salary structure adopted across Tata group airlines.

Many First Officers fear that this adjustment will negatively impact their earnings.

For the last few days several flights have been cancelled and delayed due to the ongoing mass leave by pilots.

On Tuesday, in response to the recent surge in flight disruptions by Vistara Airlines, a joint venture of Tata and SIA airlines, the Directorate General of Civil Aviation (DGCA), citing various reasons including crew unavailability, mandated that the airline submit daily reports detailing flights that have been cancelled or delayed.

Meanwhile, the Ministry of Civil Aviation (MoCA) is also monitoring Vistara’s flight cancellations.

"Ministry of Civil Aviation is monitoring the situation of Vistara flight cancellations. However, flight operations are managed by airlines themselves. Airlines have to comply with DGCA norms to ensure passenger facilitation in case of cancellation or delay of flights," said MoCA on X.

On Monday the airline had said that in light of crew unavailability and other factors, it had experienced a notable uptick in cancellations and delays.

“We have had a significant number of flight cancellations and delays in the past few days due to various reasons, including crew unavailability," said an airline spokesperson.