REPORT: Why fog, sandstorms delay flights at DXB
Delays at Dubai Airports during fog or a sandstorm are largely caused by an increase in safety measures that the authorities impose during times of poor visibility, according to a senior official.
The separation or safe distance required between landing aircraft at Dubai International Airport (DXB) is increased to the maximum during fog or sandstorm days, Darren Williams, vice-president, airside operations DXB Operations Unit told Arabian Business.
In the past two months, a number of flights were delayed, diverted, or cancelled across the UAE airports due to heavy morning fog.
The phenomenon generally occurs once a month between November and March every year. When it does, there's a significant impact for one of the busiest airports in the world, where somewhere between 1,100 and 1,200 flights are landing or taking off every day.
DXB is equipped with the world’s best instrument landing system (CAT IIIB) that allows it to operate in visibility as low as 50 metres.
On a clear, blue sky day, the minimum distance between aeroplanes, closing in to land, is between 3 and 8 nautical miles, depending on the size of the aircraft following the one landing. Therefore, the separation distance helps in reducing wind turbulence impact.
“Fog is an event which is obviously outside our control. The equipment that we have installed [at DXB] is the best equipment currently in the industry,” Williams said.
“When we move into low visibility operations during fog, it is very much an auto-land by the aircraft as the pilot’s visibility from the cockpit is zero. During auto-landing, we have to increase the safety margin since the pilot is not able to visually see any other aircraft.
“So instead of going to 3 or 8 nautical miles, we now have to go to 10 or 12 nautical miles which builds in the safety buffer to ensure that every aircraft’s landing signal isn’t interfered by any other aircraft.”
According to Williams, the only way to resolve the flight delays during fog is to cut the capacity at the airport on a daily basis, while still aiming to serve as many aircraft as possible.
“As any other airport, we also declare our runway slots. But during those 2 percent of the days when you have those ‘freak’ [fog or sandstorm] events, what we can do is we work with the airlines and Air Traffic Control to mitigate [traffic disruption] and have the best recovery plans possible.”
While Dubai Airports has looked at the option of having a “Ground Based Augmentation System” (GBAS), a global positioning system (GPS), the official said they will consider adapting the technology when it becomes “fully compatible” with CAT IIIB.
“We have met multiple suppliers through Dubai Air Navigation Services and ourselves but GBAS is not certified for CAT IIIB.
"If and when it is ready, we will easily adopt to that as the future growth of Dubai World Central [Al Maktoum International Airport] has been designed in anticipation of that system,” Williams added.