New Delhi: Pratt & Whitney will provide spare engines within 40 days to get all grounded Airbus SE A320neo aircraft at India’s IndiGo flying again, with the first delivery scheduled for Wednesday, people with direct knowledge of the matter said.

The engine maker communicated its plan on Tuesday to the jet’s biggest customer, the people said, asking not to be identified because the matter is confidential. IndiGo grounded 11 aircraft last week, complying with a directive from India’s air-safety regulator, leading to the cancellation of hundreds of flights.

A representative at IndiGo, operated by InterGlobe Aviation Ltd, didn’t immediately respond to a request for comments. A Pratt representative in the US didn’t reply to an email sent outside regular business hours.

Getting the idle aircraft off the ground is crucial for IndiGo, which has already lost more than $600 million in market value this month as the engines featuring a flawed seal led to in-service shutdowns. The plan would also provide a breather to the unit of United Technologies Corp. that’s struggling to get its most ambitious turbine program back on track after issues ranging from delivery delays to groundings.

Pratt president Robert F. Leduc said on Friday the fleet in India “will be back up in the air flying" by end-April.

The company originally planned to replace all defective components by June for the latest snag caused by the so-called knife-edge compressor, which meant some planes would fly with one affected engine for almost three more months. Pratt’s proposal was a fix that would see at least one engine featuring an older seal reinstated on planes while it worked on a more permanent solution.

India said last week that’s not acceptable, although the European Aviation Safety Agency, the primary regulator for Airbus planes, repeated guidance that the jets are safe if they have a single affected turbine. Bloomberg