All About Aircraft Instrumentation Systems

With the increasing complexity of aircraft, the number of instrumentation systems in an aircraft is growing. Any instrumentation system helps the pilot fly the aircraft, be it with navigational information, or engine operating information.

All systems feature a back and forth relationship between a sensor and an indicator. Information is read by the sensor and is conveyed via an electric, hydraulic, or pneumatic system to the display. An analog system features both the sensor and the indicator. A pilot will need to interpret the data and make any necessary adjustments. Digital systems differ in that the display isn’t directly connected to the sensor. Digital data buses are increasingly used to manage the various electronic instrument systems in an aircraft. Wires share message carrying from many instruments by digitally encoding the signal for each. The various instruments can be classified in terms of the data they supply. Flight navigational instruments and engine instruments are two of the main classifications of instruments.

Flight Instruments

Flight instruments are located inside the cockpit of an aircraft and can be separated into two categories which are pitot-static and gyroscopic. A pitot static system utilizes the static air pressure and the dynamic pressure to the motion of the aircraft through the air. Airspeed indicators, vertical speed indicators, and altimeters are all analog systems that are connected to the pitot static system. Each of these devices rely on the pitot static system to intake air and duct it through various chambers. Without the pitot static system, these instruments would have no way to gauge changes in pressure levels in the aircraft. Three gyroscopic systems accompany the three pitot static systems in what is colloquially known as the 6-pack of instruments.

Engine Instruments

Aircraft engines are subject to numerous stresses that need to be constantly monitored by the pilot. The instruments in this category measure the operating parameters of an aircraft engine usually concerning the pressure, quantity, or temperature. Engine fuel levels and temperature are strong indicators of the health of the engine. It is no surprise therefore that various instruments such as an exhaust gas temperature gauge and oil and carburetor gauge are inserted in or around the engine.

To fully discuss the instrumentation parts and systems within an aircraft, the topic of digitization, particularly inside the cockpit, must be addressed. With advances in technology, aircraft are being fitted with glass cockpits rather than the analog instruments mentioned earlier. While this new system is praised for providing more accuracy and limiting the amount of information that a pilot must interpret, digital systems should be assessed in terms of the risk of an electrical fire.