IGI streamlines runway use,but fog may change rules

But winter may throw all calculations awry as only the new runway is equipped to handle fog — with instrument landing system on both sides to facilitate arrivals and departures in visibility less than 500 metres. Plus,the number of domestic aircraft equipped with the instrument landing system is not high.

The IGI authorities,therefore,plan to use the new runway for the landing of domestic flights.

“In case of congestion,domestic flights will be diverted to the new runway for landing,” said V Somasundaram,Executive Director for Air Traffic Management,Airports Authority of India. “Our motive is to reduce the hovering time.”

But some part of the new runway cannot be used at all times,“due to obstructions like the Shiv Murti which come in the flight path while landing,” he said.

The airport witnesses an over 80 per cent domestic movement. But the stoppage of mixed mode of runway use may have other fallout — an increase in taxiing time owing to an extra distance of nine kms.

Since the taxiway connecting the two runways is on the Dwarka side,the planes using the new runway will spend 30 minutes taxiing in good weather and 45 minutes during poor visibility. This results in wastage of precious aviation turbine fuel.

The new runway,due to large open spaces around,is affected by denser fog that stays for longer hours.

Somasundaram said standard guidelines set by the Directorate General of Civil Aviation need to be followed when runway visibility range falls below Category IIIB (below 50 metres).

“There are certain requirements that an aircraft has to fulfil while landing in low visibility. Mixed mode operations may have to be stopped in such a situation as more distance — at least 16 miles — has to be maintained between two approaching aircraft,” he said.

The decision to stop mixed mode use,however,may not have to be taken unless there is huge backlog of flights.

“There is always a bulk of domestic flights that will use runway 28,” he said. “In case of congestion after fog,domestic flights will be able to use runway 29. This will lead to an equal distribution among two runways and help ease congestion.”

WHAT IS MIXED MODE
In the mixed mode runway use,which became operative on October 22,domestic arrivals and departures take place from the main runway — 28-10 — which is very close to the domestic terminal.

This helps cut down the taxiing time,which is usually over 30 minutes. The international arrivals and departures take place from the new runway — 29-11 — which is closer to the international terminal T2.

“While the new runway eased congestion to a large extent,domestic airlines were not benefiting due to the long taxiing time. The new process has helped reduce that,” said a senior civil aviation ministry official.