The Directorate General of Civil Aviation has ordered a safety audit of domestic airline IndiGo over Pratt & Whitney’s engines that have been facing snags recently, reports said. The showcause notice was issued last week to IndiGo’s chief operating officer and engineering chief.

In India, IndiGo and GoAir operate Pratt & Whitney-powered Airbus A320 neo planes. The aircraft has been facing engine problems since the induction of the United States firm’s engines in the fleet three years ago, PTI reported.

The DGCA issued the notice after suspecting whether IndiGo was reporting all snags. “We do detailed audit of all airlines at least once in a year,” DGCA chief BS Bhullar told PTI. “IndiGo is this month, some other [airline would be audited] in June. Every audit involves some actions.”

IndiGo’s engineering and operations will be under the scanner in the audit, according to reports. “We can confirm that IndiGo operation is running in even more stringent ways as prescribed by regulatory framework,” IndiGo spokesperson said in a statement, according to The Times of India. “As this is an ongoing audit we can only comment after the process is over.”

Quoting sources, NDTV reported that at least 18 cases of mid-air engine failures or problems have been reported on IndiGo and GoAir aircraft with A-320neo aircraft in 2019.

Earlier this month, the Delhi High Court had sought responses from the Centre and the DGCA on a plea seeking to ground all Airbus 320neo aircraft fitted with the Pratt & Whitney engines.