IndiGo says it has not had any unplanned flight cancellations arising from on-going issues with the Pratt & Whitney PW1100G engines that power its Airbus A320neos.

The airline's comments follow media reports that it had cancelled 85 flights in the last week due to issues with the PW1100G powerplants. The airline denied this but said that there have been days where it had to park up to nine A320neos due to the lack of spare engines.

IndiGo adds, however, that flights were not affected since it has already "factored in the reduced aircraft capacity while scheduling flights".

Among the known issues with IndiGo's PW1100Gs have been premature degradation of the combustor chamber lining, and premature wear of the number 3 bearing seal. IndiGo expects that it may take another 12 to 18 months before design changes aimed at addressing the problems are fully implemented by P&W.

However, it reveals that a new tax change in the country is delaying replacement powerplants and has caused some "unplanned short-term flight cancellations".

IndiGo adds that it has grounded four A320neos "for as much as three weeks" as their spare engines are awaiting customs clearance.

"We are waiting clarification on certain provisions affecting the entire airline industry post the implementation of GST. Our understanding is that the GST was not intended to create an additional fiscal burden on the airline industry. This unpredictable situation did lead to some unplanned short-term flight cancellations... We are engaged in ongoing discussions with the relevant authorities and hope to receive the GST clarification soon."

New Delhi implemented a new goods & service tax scheme, effective 1 July. This affects the tax treatment of imported aircraft and engines.

Flight Fleets Analzyer lists the four grounded A320neos as bearing the registrations: VT-ITS, VT-ITG, VT-ITJ, VT-ITM. The first three aircraft are owned by the carrier, while VT-ITM is owned by Avolon Aerospace Leasing.

Source: Cirium Dashboard