Airport sources say the glidepath, a navigational aid, is very important as it enables pilots to land even when visibility is drastically reduced due to fog or smog.

``The glidepath, which has been switched off due to the Runway Extension Project currently being undertaken up by the Airports Authority of India, is expected to be back in operation from November 30,'' Ahmedabad Airport Director R.C. Chitkara said.

Meanwhile, operators of most of the private and the government-owned airlines complained that their flight schedules had been badly disrupted as their pilots were not able to land their aircraft at the smog-enveloped runway in the morning hours due to the non-functional glidepath. They said that landing of flights at the airport in the absence of a glidepath depended on the equipment aboard an aircraft.

``Around 15 Indian Airlines (IA) aircrafts coming to Ahmedabad have either been unable to land at the airport in the morning or have been rescheduled ever since the navigational aids were switched off,'' IA airport manager Rajnish Bagga said.

He said that IA had so far spent around Rs 20 lakh on providing food and hotel accommodation to its passengers who had been stranded at the Ahmedabad airport due to disruption in flight schedules.

Air India's (AI) manager (Gujarat) T.R. Heerji said that AI's international passengers had also been badly inconvenienced due to the disruption of foreign-bound flights. ``We have not been able to connect our airbuses to the New York and Chicago-bound Boeings 747,'' Heerji said. He, however, refused to disclose how much loss AI was incurring by way of providing food and hotel accommodation to stranded passengers.

Jet Airways (JA) Airport Manager Harjinder Singh, however, said that the flight schedules of JA had not suffered much. ``Our flight schedules have not been affected because most of the JA flights arrive at Ahmedabad airport later in the day,'' Singh said. The airline operators were all unanimous in their view that the glidepath should have been switched off in March when the problem of smog was not there.

Stating that the glidepath had been switched off as per the safety regulations of the International Civil Aviation Organisation, airport sources said that switching off the navigation aid in March would have delayed the ongoing Runway Extension Project.