Why Delhi Airport Will See 7% Flight Cancellations

'Delhi airport handles 1,450 aircraft movements per day. Of these, 114 daily movements will be cancelled during the runway upgrade.'

About 7.5 per cent daily flights to and from the Delhi airport will be cancelled between June 15 and September 15 as one of its four runways undergoes an upgrade, says Delhi International Airport Limited (DIAL) CEO Videh Kumar Jaipuriar.

The GMR Group-led DIAL operates the Delhi airport, which is the largest in the country.

"Delhi airport handles 1,450 aircraft movements per day. Of these, 114 daily movements will be cancelled during the runway upgrade," adds Jaipuriar.

"The number of cancellations will be in the range of 7 to 7.5 per cent, compared to the usual 3 to 4 per cent on a normal day. However, this time we have coordinated with airlines in advance and rescheduled flights accordingly, which will help reduce any cascading impact," he says.

Referring to a similar upgrade effort earlier this year, he adds, "Last time, the lack of proper rescheduling led to cascading disruptions when wind patterns changed. This time, the impact on passengers will be much lower.

"Since they've been informed in advance, they will have enough time to rebook or make alternative arrangements."

The upgrade of runway 10/28 will include installing an instrument landing system (ILS) and make it compliant with CAT III-B operations.

CAT III-B is a precision landing system that allows aircraft to land in very low visibility conditions, such as dense fog.

It was originally scheduled for April-May. However, unexpected changes in wind patterns during that time severely affected flight operations, causing delays.

As a result, the ministry of civil aviation -- on April 21 -- directed DIAL to postpone the upgrade and resume operations on the runway.

The runway was made operational again on May 6, and the upgrade was deferred to June 15-September 15.

"The revised timeline was agreed upon by all airlines," says Jaipuriar.

Following this, airlines collaborated with DIAL to rework slot allocations and align with the revised arrival capacity.

"The objective was to ensure optimum use of available runway capacity while maintaining on-time performance," he adds.

"During the fog season, the arrival capacity of all runways comes down due to safety concerns, as arriving aircraft have to be spaced out," Jaipuriar says.

"In case of westerly winds, arrivals drop from 42 per hour to 30 during CAT III-B operations. But with easterly winds, arrivals fall sharply from 42 per hour to just 15.

"Once the upgrade is complete, this number will go up to 30 even with easterly winds, significantly improving efficiency," he adds.

"Every hour of fog disruption takes three hours for us to return to normal operations. This becomes much worse with easterly winds, where every hour of disruption takes six hours to recover.

"This impacts not just Delhi airport but also nearby ones. Therefore, we decided to upgrade runway 10/28 and make it ready to handle CAT III-B flight operations," he says.

Jaipuriar also acknowledges the growing impact of changing weather conditions on airport operations.

"We are conducting a study as part of our climate change mitigation plan. This kind of erratic weather behaviour is increasing every year. Based on the findings, we will develop a mitigation strategy."

Feature Presentation: Ashish Narsale/Rediff