IndiGo Airlines (6E, Delhi Int'l) has grounded five A320neo at Delhi Int'l due to technical issues with Pratt & Whitney PW1100 Geared Turbo Fan engines, the Times of India has reported.

"The release of additional spare engines has been initiated by P&W [Pratt & Whitney] so that all aircraft are expected to be back in service in the second half of August," the airline said.

Flightradar24 ADS-B data shows that the grounded units are: VT-ITN (msn 7252), VT-ITR (msn 7396), VT-ITT (msn 7504), VT-ITY (msn 6946), and VT-ITZ (msn 7892). Additionally, VT-ITK (msn 7001) has been grounded at Coimbatore since July 25 in what seems to be an unrelated development.

According to the ch-aviation fleets module, IndiGo currently operates thirty-nine A320neo. The airline is the world's largest operator of the type and still has a further 366 units, as well as twenty-five A321neo, on order with Airbus.

It is the second large-scale grounding of A320neo operated by IndiGo, following an earlier instance in March when India's Directorate General of Civil Aviation (DGCA) ordered the airline to ground eight aircraft. At that time, the order also affected three A320neo operated by fellow Indian LCC, GoAir (G8, Mumbai Int'l). The grounding lasted through the second half of April.

The manufacturing issues related to the knife edge seal on the modified aft hub of the high-pressure compressors have also caused a three-month-long gap in deliveries of the engines.