Flight training courses for pilots with GPWS

How can you protect the aircraft from collisions with the ground and other obstacles? First of all, flight routes, procedures for maneuvering around the airfield are established. Safe flight altitudes are published for specific routes and procedures, as well as for entire areas (for example, in an aerodrome area or in the vectoring sector). The flight with all the established restrictions, as well as the observance of meteorological minima ensures the safe passage of all obstacles. However, there is still a risk of collision of aircraft with obstacles. It is primarily about the human factor. This may be a crew navigation error or a dispatcher error. In addition, although extremely unlikely, navigation equipment failures are potentially possible. GPWS and EGPWS’s ground proximity warning systems are the last line of defense against collisions with obstacles.

GPWS signals about the dangerous proximity of the earth are formed on the basis of an estimate of the true flight altitude (as determined by radio altimeter), vertical speed, position relative to the glide path and aircraft configuration, i.e. chassis position and wing mechanization.

The height adjustment on the landing is also a function of GPWS. In this case, signals of 1000 and 500 feet are formed on the basis of relative barometric altitude, and signals of 100, 50, 30, 20, and 10 feet, according to radio altimeters.

Obviously, when flying in highlands, traditional GPWS can be extremely inefficient. When flying a course on a mountain with a steep slope, the time that passes from triggering an alarm to a collision is not enough to avoid an obstacle, and when colliding with a vertical surface at high elevations, the alarm does not even have time to work. A serious drawback of GPWS is the inability of the system to issue warnings of proximity to the ground if the aircraft is in a landing configuration and decreases at a normal vertical speed.

The next generation of ground proximity warning systems is called EGPWS (Enhanced-GPWS, i.e. improved). The main difference of EGPWS from the base GPWS is the FLTA (Forward Looking Terrain Avoidance) function, i.e. the function of assessing the threat of collision with obstacles on the flight course. The EGPWS includes an updated database that includes information about obstacles around major aerodromes and less accurate relief data for the flight region. Information from the database using the appropriate mode is displayed on the navigation displays in the cockpit.

With timely and correct actions by the crew, a safe divergence with the obstacle is ensured. The system may be limited to manual operation by the crew, as a rule, three switches are installed in the cabin, which disconnect the system from the system about the relief, the position of the landing gear or the position of the wing mechanization.

After the appearance of EGPWS in the United States, the TSO-C151B standard was adopted, which clearly stated the requirements of such systems, this standard is valid today. This paper has introduced a classification of collision avoidance systems with the ground. Systems that include a database of terrain and obstacles, and therefore have a FLTA function, are assigned to the TAWS (Terrain Awareness and Warning System) systems. In other words, EGPWS is a special case of TAWS.

For training questions, please contact us by email: trto@skyavia.com.ua or by phone +38 044 337 17 75.