Landing in rain or fog is not an easy task, but in some cases pilots have to deal with it. Despite the fact that weather forecasts are considered even before departure, at the time the flight commander made a decision about the flight, while the aircraft is in the air, the weather at the destination can change significantly for the worse. What actions are taken in this case?
Sometimes in such a situation, landing is carried out at the alternate airport. In other situations, the board nevertheless landed, using those methods and equipment that are designed specifically for this case.
Minima and norms
There are general requirements used in assessing the risks of landing in difficult and non-flying weather. They are generally based on visibility indicators, and most aerodromes indicate the ability to take a side with visibility from 900 meters. The aircraft is able to land successfully with visibility from 500 meters. Hypothetically, the pilot is able to land at zero visibility due to instruments, but in practice this is not allowed, even if they are confident in the skill of a particular commander. Blind landing on civilian flights is not carried out, and the requirements for each aerodrome and onboard are formulated individually, taking into account all the factors that play a role in ensuring the safety of passengers and crew.
Landing decision
The airport itself may refuse to land - in dangerous weather conditions, the dispatcher informs the crews that the airfield is temporarily closed, and then they have to land at emergency points located nearby. In other cases, the decision is made by the first pilot, who, in fact, is responsible for this issue. He can enter the first or second round, evaluating the situation and completing the maneuvers necessary for a safe landing. Conditions of poor visibility in rain or fog can reduce visual control to tens of meters, wind or wet landing strip will further complicate the situation. However, modern instruments and systems will allow an experienced pilot to successfully cope with the task. After all, airplanes fly at night, when visibility is in any case low, and there are no problems landing or taking off.
Equipment and systems for safe landing
In fog and rain, pilots need help with landing, and it is provided with special systems. The importance of their use cannot be overestimated, because we are talking about high speeds that allow you to overcome hundreds of meters, kilometers in seconds. The most common system used at airports around the world is the heading glide path system (ILS).
The principle of the course-glide path system
The course-glide path system is a pair of antennas that provide signals along the straight line in two planes (vertical and horizontal), along which the board decreases and enters the landing.The system creates with its radio signals a path outlined by two lines, beyond which the plane cannot go — instruments will immediately inform the pilots that a deviation has occurred. Thus, a safe path is laid on the board, along which it can follow almost blindly. This system successfully works even with an autopilot, creating a minimum of landing problems for the crew, removing a lot of risks.
Today, such systems are available in many variations, they can be of different accuracy. Modifications that make it possible to land even at zero visibility due to increased accuracy are extremely expensive in price, and therefore they are not available everywhere. But even outdated solutions bring many benefits, tens of times increasing the safety of landing in difficult weather.
Aircraft landing process
Even in conditions of good visibility, the aircraft does not always go on the move on the fly, at first it needs to decrease, and sometimes to take its place in the line for maneuvers. The plane can circle and go on the glide path. The glide path is a special trajectory before landing, when the plane must fly at a strictly defined angle. The system of radio-glide path beacons helps to maintain the desired course in rain and fog, and other aircraft systems contribute to maintaining the optimum course and tilt. To ensure a safe landing, the pilot must adhere to an angle of 2-4.5 degrees. The Soviet standard was 2.4 degrees, and the modern international standard strongly recommends adhering to a slope of 3 degrees.And the system helps the pilot to adhere to just such an inclination and trajectory, smoothly going down.
Other support features
Many people noticed that all runways at airfields are highlighted. Can be used as ordinary lights, and fog lighting technology of increased efficiency, which is noticeable even through fog. Visual guidelines are also extremely important, they really help pilots to sit in the rain and dusk.
Thus, landing in rain or fog is carried out mainly by instruments. The airport can either accept the aircraft or refuse because of difficult weather conditions, declaring a temporary closure due to non-flying weather. If it is possible to take the board, the pilot takes him to the glide path and walks along the beacon.
