New Delhi, Feb. 26 (PTI): Domestic airlines have lost crores of rupees in flight disruptions caused by intermittent fog this winter.

About 1,640 flights were cancelled because of thick fog blanket for 7 to 10 days since December. Low-cost carrier Air Deccan was the worst sufferer, cancelling 805 flights.

Indian Airlines came out with an estimated loss of Rs 1.83 crore, the sources said. The private carriers did not reveal details of financial loss.

Indian Airlines was the only domestic carrier which had pilots trained to use the instrument-landing system category IIIB, along with Air-India and the international carriers. So they could utilise the system installed in Delhi by the Airports Authority of India during the fog.

According to rules, only trained pilots who are authorised by the Directorate General of Civil Aviation (DGCA) can use the Cat-III system.

The civil aviation ministry has already warned the private domestic airlines that if they do not have trained pilots by this year-end, they would not be allowed to operate from Delhi or other fog-affected airports.

The DGCA has also been coordinating with various airlines to speed up the training.

Despite the DGCA raising the retirement age of commercial pilots from 60 to 65 years, there is a shortfall of 880 pilots in the country.

The projected requirement in the next five years, as given by new and upcoming airlines, is 4,800.