BENGALURU (Reuters) – IndiGo, India’s biggest airline by market share, on Monday reported a rise in quarterly profit, helped by increased efficiencies and a boost from lower fuel costs.

Revenue per available seat kilometer (RASK) rose 5.6% for the three months ended Dec 31. Typically, the higher the RASK, the more profitable an airline is.

Fuel costs for the quarter dropped 2% to 33.42 billion rupees.

The airline’s owner, Interglobe Aviation Ltd, said net profit for the quarter came in at 4.90 billion rupees ($68.95 million), compared with 1.91 billion rupees in the same period last year.

Revenue from operations rose 25.5% to 99.32 billion rupees.

However, expenses at the airline rose 21.5% amid higher maintenance costs after it was forced to replace the Pratt & Whitney engines on its fleet of Airbus A320neo planes which have been linked to in-flight engine shutdowns.

($1 = 71.0700 rupees)