NEW DELHI (BLOOMBERG) - India barred 90 pilots from flying Boeing Co 737 Max jets after finding problems with a simulator they'd trained on to operate the aircraft, which the country cleared to fly again in August following a global grounding.

A routine check of the simulator revealed deficiencies, and an investigation is underway to discover what caused them, Mr Arun Kumar, chief of India's Directorate General of Civil Aviation, told Bloomberg News.

Indian regulators found glitches with the flight controls and a stick shaker, according to people familiar with the matter.

Boeing owns the simulator, which was provided to SpiceJet Ltd and new carrier Akasa Air for pilot training, the people said, asking not to be identified because the information wasn't public.

Boeing installed the simulator in Noida, near New Delhi, meeting a requirement by India to clear the 737 Max to return to the country's skies.

The aircraft model, a Boeing bestseller, was grounded globally in March 2019 following crashes in Indonesia and Ethiopia that killed everyone on both flights. It has returned to service in most markets, besides China.

"We have barred these pilots from flying Max and they have to retrain successfully," Mr Kumar said. "We will take strict action against those found responsible for the lapse."

A Boeing representative in India didn't have an immediate comment on the matter.

SpiceJet, the only Indian airline currently using the 737 Max, said 90 of its pilots have been restricted from flying the plane until they retrain.

SpiceJet operates 11 of the planes and has enough pilots to keep flying them, a representative of the carrier said. A fleet that size requires 144 pilots in total, he said.

Akasa is due to start commercial services in June, pending approvals.