Troubled Indian carrier Kingfisher Airlines has been forced to ground 15 aircraft because it is unable to pay their maintenance costs, the Economic Times newspaper said yesterday. The business daily quoted one unnamed executive as saying that the cost of keeping the aircraft at airports around the country was \"killing\" the company financially. More than 50 pilots are also said to have left the carrier last week, the report said, quoting an unnamed aviation industry insider with knowledge of the issue. A Kingfisher spokesman said the company had no comment to make on the reported groundings and added on the pilots issue: \"We have adequate number of pilots to operate as per the revised schedule.\" Article continues below Kingfisher is in desperate need of fresh capital and has cut back on dozens of unprofitable routes, amid heavy financial losses that have raised questions about its financial viability.