Brief About Aeronautic Navigation Instruments

Visual Flight Rules, or VFR, refers to a set of guidelines under which a pilot operates an aircraft in weather conditions clear enough for the pilot to see where the aircraft is going. VFR requires a pilot to be able to see outside the cockpit, control the aircraft’s altitude, navigate, and avoid other obstacles and aircraft. Different governing bodies have unique requirements for VFR flight, but factors such as minimum visibility and distance from clouds are always taken into consideration. The opposite of VFR flight is IFR, or instrument flight rules, in which the operation of the aircraft is done primarily through the use of instruments rather than visual reference. In modern aircraft, there are many instruments at the pilot’s disposal during both VFR and IFR flight. While VFR flight has the added bonus of visibility, instruments are still key. This blog will cover the primary aeronautic navigation instruments necessary for VFR flight.

The most basic Instrument of Air Navigation for a VFR pilot is the magnetic compass. This aircraft part is operated via a magnetic needle that aligns itself to the field lines of earth’s magnetic fields, allowing the pilot to determine the aircraft’s direction relative to magnetic north. A standard magnetic compass will show north, south, east, and west, along with marked intervals every 30 degrees. While many types of magnetic compasses are used in aircraft, the floating magnet type is the most prevalent. In this configuration, the needle is integrated into a floating disk that holds markings of the compass rose on its circumference.

Another important aeronautical navigation tool is the Automatic Direction Finder. The ADF works in concert with the non-directional beacon, a ground-based transmitter which transmits radio signals in all directions. The ADF is fitted with two aerials, a receiver, and an indicator. The indicator points to the selected NDB ground station to provide a relative location guiding the aircraft. The ground radar is another critical air navigation aid. The radar receives energy in the form of very short pulses to determine the range and bearing of an object. Objects along the part of the pulses will reflect and scatter some of the energy, but the energy that makes it back to the receiver will allow for a calculation of range and bearing.

A navigation tool that nearly everyone will be familiar with is GPS, or Global Positioning System. GPS Navigation Systems are satellite-based radio navigation tools used by civilian and professional pilots alike to accurately recognize their position at any point on the planet. GPS was developed by the United States Department of Defense and is made up of three segments: space, control, and user. The space segment consists of a collection of 26 satellites orbiting the planet, each transmitting a unique code and navigation information in the UHF band. The control segment features a master control station and multiple monitoring stations and ground antennas at work. The ground antennas monitor the satellites and communicate with them. The final user segment refers to the receiving end of the system.