Indian budget carrier Akasa Air has accused the aviation regulator of causing it "significant financial and operational hardship" by not intervening to stop pilots from abruptly quitting and disrupting operations, legal filings showed.

Over 40 of more than 450 pilots have recently quit Akasa without serving their notice, leading to cancellations of around 18% of the 3,500 flights it usually runs a month in August.

Akasa is suing some of the pilots for alleged contractual violations, and has warned in court that it might have to shut down if the exits continue.

India mandates a notice period of 6-12 months for pilots which some pilot organisations are challenging in court. Akasa argues its contractual obligations with pilots remain in force, and is suing the regulator for not intervening in the public interest.

In its 265-page legal filing, made on Sept. 14 and seen by Reuters, Akasa accused the Directorate General of Civil Aviation (DGCA) of being "unwilling to take any action", which resulted in "significant financial and operational hardship" as well as "reputational loss".

The DGCA's inaction has a "cascading effect on the stability" of the Indian aviation sector, it added.

A DGCA official said the regulator cannot comment, as the case was being heard in court. An Akasa spokesperson said the airline was in discussion with the DGCA on the matter.

The DGCA will present its response at a hearing on Friday.

Launched in August 2022, Akasa is India's newest airline but it is not the only one dealing with challenges. Go Air, which is grounded, is facing bankruptcy, and SpiceJet is struggling amid a funding crunch.

Akasa's market share in August fell to 4.2% from 5.2% in July.

The filings showed that before going to court, Akasa wrote to Aviation Minister Jyotiraditya Scindia, saying sudden pilot resignations would "encourage" foreign airlines to resort to similar poaching practices, and given the global shortage of pilots, the "impact in India will be felt very soon".

Akasa also told the court it had made alternate bookings for passengers whose flights were cancelled, saying it was "absurd" that it was buying tickets from airlines to which its pilots are "defecting".

The aviation ministry did not immediately respond to a request for comment.

(Reporting by Arpan Chaturvedi; Additional reporting by Aditi Shah; editing by Aditya Kalra and Jason Neely and Miral Fahmy)