It happens every year. With the advent of winter, a blanket of fog descends over northern Pakistan. Visibility at airports in the region drops below the level needed for flights to operate. There are delays and flight cancellations. Passengers suffer. Workers returning to jobs in the Middle East miss visa expiration deadlines and sometimes are not able to return at all. Fistfights break out in departure lounges with airline staff. Airlines and related businesses suffer losses.

None of this needs to happen. For many years, technology has existed for airports to stay open in dense fog or near zero visibility. Charles de Gaulle airport in Paris for instance, stays open round the clock, every single day of the year. Planes land and take off no matter what the visibility. And the same applies to most major European airports.

How is this possible? And why do our airports here in Pakistan shut down at the first hint of fog? The answer has to do with the methods pilots use to land airplanes. There are two possibilities. The first is to land visually. This is only possible if pilots are able to clearly see the runway. So visual landings are not possible when the runway is covered by fog. The second is to land by using what is known as an instrument landing system - ILS.

ILS landings require both the airport runway and the airplane to be fitted with special equipment. The runway is fitted with directional radio beacons. The airplane is fitted with a receiver that tunes into the beacons and tells the pilot his location - height and distance - from the runway. Hence landing without visual reference becomes possible. However this depends on the type of ILS system in use at the airport.

The International Civil Aviation Organization (ICAO) classifies ILS systems into three categories. The first category called, not surprisingly, Category I requires that visibility on the runway be at least 1800 ft for a plane to land. Category II requires it to be 1200 ft. Category III is itself divided into three categories. The first, IIIa, requires a minimum visibility of 750 ft, IIIb requires 150 ft, and IIIc, believe it or not, has no minimum.

However Category IIIc is not in use anywhere in the world. This is because even though it is technically possible to land a plane on the runway in zero visibility, there remains the little matter of getting from there to the arrival gate. This part can’t be automated. And if the pilot can’t see anything then he has no way to move away from the runway.

Category III landings have another peculiarity worth mentioning. The landing must be done by an on board computer. Pilots are allowed only to watch and supervise. The computer will land the airplane on the runway. Pilots take control when the landing is complete and the airplane starts to slow down. Most airplanes using European airports are equipped with such ‘auto landing’ systems.

The problem in Pakistan is that most of our airports, including some that serve major cities like Multan and Peshawar, have no ILS at all. Pilots have to operate visually. And the moment that fog drifts in, the airport has to close.

Islamabad and Faisalabad have Category I systems so runway visibility has to be at least 1800 ft for the airport to operate. Only Lahore has a Category II system that lets it stay open until visibility drops below 1200ft.

What we need to do to keep critical airports such as Multan, Lahore, Islamabad and Peshawar open at all times during winter is to equip all of them with Category IIIb landing systems. This will allow planes to land with visibility at 150 ft or 46 meters. And this practically guarantees round the clock operation since only rarely does visibility in fog drop below this level.

Airlines will also need to ensure that their airplanes have the necessary equipment as well. Any airline that operates to major European airports, such as PIA, will already have this equipment in most of its airplanes. And the same applies to international carriers like Emirates.

Category III ILS systems have been in use around the world for decades. There is no excuse for Pakistan not to have them. They are not cheap. But they cost only a fraction of the cost of a new airport building, several of which are being built around the country. So the money is there to install them. What seems to be missing, as in so much that is wrong in Pakistan, is a problem-solving mindset at the top levels of our government.

 The writer is Chairman of Mustaqbil Pakistan.

READ MORE: A leather jacket