Airplanes generate revenue when they are in the air, and their unscheduled grounding or cancellation of flights is a cause of great concern for airlines around the world. Whether it is an airline, an airport, or a ground handling agency, each aviation-related organization tries to ensure that flights depart safely and on-time. Airports play a key role in maintaining the smooth flow of airplanes and passengers and their functions are governed by International Civil Aviation Organization (ICAO) standards and recommended practices, just like the airlines and other aviation organizations.
Runways of most airports around the world are not heated owing to the amount of energy required to heat-up their large surface areas, as well as the associated maintenance issues of built-in heating equipment.
With recent technological advancements, researchers are experimenting with optimized heating mechanisms for runways, however, they have not been practically implemented yet.
So, the airport operations, although challenging enough, become even more complicated during harsh weather such as storms and heavy snowfall.
This is when the airport personnel is tested to their limits in maintaining safe aviation operations.
For example, in case of heavy snowfall, the ice and snow must be cleared off the runways and taxiways to allow airplane landings and movement on the airport.
So, how is this done?
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How do airports de-ice airport runways?
Most airports around the world utilize conventional de-icing methods such as using large plows, blowers, and other snow machines to clear runways and taxiways. They also use de-icing chemicals to discourage bonding of ice to the surface.
For airports, the main concern is avoiding the formation of ice on the runway surface, as it takes a lot of effort to be melted.
In comparison, snow can be cleared easily, and therefore, the airport crews are mostly focused on removing snow from a runway before it becomes a thick layer of ice.
Dealing With Unexpected Snowfall
Airports in extremely cold regions experience snowfall round the year and sometimes, it may be quite unexpected.
Dealing with such weather requires elevated levels of preparedness at times, such as maintaining the availability of plows and snow machines as well as trained personnel.
Thanks to these modern machines, snow is kept off the runways during snowfall to allow some airplane take-offs and landings before it accumulates again, and the cycle continues.
Use of Chemicals
Once the snow is cleared through these machines, it is a widespread practice to use chemicals such as Potassium Chlorate or Urea to treat the runway surface and discourage ice formations.
This treatment must be done either before the formation of ice on the runway or once the snow has been completely cleared.
With that said, you may be wondering if salt can be utilized on airport runways as well?
Can salt be used to reduce icing on airport runways and taxiways?
Though common salt, Sodium Chloride, is widely used on highways and tracks to reduce icing, it cannot be utilized on airport runways as it can damage aluminum skin and structure of airplanes by acting as a catalyst for rust.
Salt is known to cause rust on cars as well, but the structural integrity of an airplane is far more crucial, and utilizing salt is therefore prohibited by aviation authorities.
Other de-icing chemicals such as Urea or Potassium Chlorate that do not have the same adverse effects on Aluminum, are approved and then utilized by airport authorities.
Do airports use any automatic de-icing equipment?
Several aerodromes around the world are experimenting with innovative technologies and methods for the prevention of icing conditions. Temperature sensors integrated into the runway surface are increasingly finding their utility and the Federal Aviation Authority has issued complete guidance on how to install and operate them.
These sensors can predict ice formation on the runway surface. Based on the input from these sensors some airports have employed automated glycol dispensing systems along the runway.
However, as the glycol is poisonous for animals and makes the runway surface slippery as well, these systems are not widely used leaving this job to the snow blowers on most airports.
With each operation, there is an associated cost, and aviation equipment and materials commonly come at a premium as well.
So how costly is clearing snow from the runways and apron?
How costly is de-icing airport runways?
In addition to the cost of fuel and manpower operating heavy-duty snow plows and snow blowers, there is a significant cost associated with the de-icing chemicals.
To clear an average airport runway, anywhere between five to ten snow machines work in tandem for one or several hours. Furthermore, thousands of gallons of liquid chemicals (costing between $7 to $10 per gallon) are sprayed owing to the large runway surface area.
Considering the above, clearing ice off a runway can cost several thousand US dollars each time.
Do airplanes need de-icing in harsh winter conditions?
The de-icing of airplanes is critical for them to be flightworthy. Formation of ice on lift generating surfaces such as the wings and horizontal stabilizer disrupts the airflow over them, thus reducing the left generation and creating a safety hazard.
Moreover, the formation of ice on or near flight control surfaces such as ailerons, elevators, and rudder may also restrict their movement which makes deicing essential before take-off in icy weather.
If you have traveled during snowy weather, you may have seen deicing fluid being sprayed over the airplane. This mixture of glycol and water removes the ice and restricts its build-up during the flight as well.
Can airplane take-off or land on icy airport runways?
Have you ever seen cars slip and slide on snow, trying to catch a shred of traction all while failing to do so?
It is tough getting a car to come to a halt on snow, imagine trying to stop a 160-ton aircraft landing at 150 knots on an icy surface! Due to hydroplaning or aquaplaning, an airplane can overshoot the runway or drift-off sideways into the mud.
Therefore, the airport authorities employ aerodrome inspectors who patrol during harsh winter weather to detect ice formation on the runway.
Special Temperature Sensors
Some airports have installed special temperature sensors on the runway pavement which provide real-time information to concerned personnel if the temperature is dropping below the freezing point, thus enabling them to use de-icing materials promptly.
Air Traffic Control
In harsh weather conditions such as heavy snowfall, during the approach of an airplane, the air traffic control also provides information regarding runway conditions to pilots who then take the decision to land, hold or divert based on their airline policies.
In any case, landing on an icy runway is tricky for pilots, not just because of extraordinary effort in handling the airplane but also in terms of runways length needed. Pilots, based on their procedures, calculate, and ensure the additional runway length required for landing and prepare their approach so that they can touch down at the very start of the runway.
Regulations and inspections
The aerodrome regulations promulgated by each national aviation authority instruct the airport authorities regarding operable conditions. These regulations are developed as per standards of the International Civil Aviation Organization (ICAO) Annex-14.
Each aerodrome requires certification under these regulations, and based on its weather conditions and relevant factors, an airport manual must be developed that contains necessary procedures for de-icing based on available resources.
Keeping snow and ice off an airport runway is a constant challenge that must be managed by planning and effectively engaging snow plows and any other available equipment.
Conclusion
- Harsh weather conditions are borne by many airports around the world and it would not be difficult to envision the reduction in manhours and effort if runways could be heated.
- But since runways and apron areas are quite large in terms of surface area, heating them comes with astonishing energy costs.
- Although heated runways are being researched on, for now, airports must rely on conventional de-icing techniques to keep operating.
- In addition to clearing snow and ice off a runway, deicing an aircraft is quite essential during these weather conditions. Ice formation on the aircraft can hamper the lift generation and maneuverability of an airplane in the air.
- Whenever you are flying in harsh weather conditions the next time, do not worry, the de-icing machines and personnel are hard at work to ensure that you fly safely and on time. Safe flying.
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