Sensors are a part of everyday life. Aircraft rely on sensors, not only as an integral part of their guidance system, but also for monitoring internal conditions and measuring fluids like fuel. In this article, we look at the many types of sensors used in commercial aircraft.
Many sensors are utilized throughout an aircraft; however, those used to monitor pressure are the most common. Pressure sensors not only track the changes in pressure, but they also provide a response that balances out pressure in each specific environment. Additionally, as force is the application of pressure over a given area, force sensors also fall under the category of pressure sensors.
Pressure sensors are used to monitor internal pressure both in the cabin and the cargo area through cabin pressure indicators and cabin pressure control sensors. Pressure sensors are also used within the cockpit as a part of the autopilot controls, as well as in the brake pedal and in the potentiometers.
On the operational side, pressure sensors are used in/for the following:
- Speed sensors
- In the engine to measure fluid levels
- Load sensors to measure the lift of the aircraft and the load on the landing gear
- Position sensors (for both the whole aircraft and its various components)
- Torque sensors used for the brakes
- Measuring the steering feedback of the nose wheel
- The center of gravity sensors
Many of the areas mentioned above that use pressure sensors are covered in more detail below, where we look at some of the different areas where sensors are used, but they have also been mentioned here because they fall within this sensor class. As it is such a widely used class of sensors, it is worth mentioning pressure systems as a whole.
Instrument and Operational Sensors
Instrument and operational sensors encompass everything that helps the aircraft to fly safely. Speed sensors (airspeed sensors, vertical speed sensors and altimeters) are used to measure how fast the aircraft is going. Position sensors—one example being variable transformer sensors—are used to measure where the aircraft is as well as measuring the position of various components of the aircraft (for example, the reverse thrusters), and force and vibration sensors are used to measure the torque and force that an aircraft exhibits, both in-flight and when braking.
Other sensors helping pilots ensure a smooth flight include altitude sensors, and magnetometers and gyroscopes to better direct the aircraft.
Sensors in the Engine
Due to the prolonged work done by an aircraft engine, many different sensors are required to ensure the engine is running both optimally and safely. These include monitoring the levels of fuel and oil, tachometers, and temperature sensors. Of all these sensors, the temperature sensors are by far the most used as they can prevent various components within the engine (and the aircraft in general) from overheating and posing a safety risk.
Temperature sensors are used to measure the temperature of fuel, hydraulic oils and coolants within the engine system, as well monitor internal temperatures within the cabin and other areas of the aircraft.
Data Monitoring Networks
As a result of the plethora of sensors used, from the engine to the internal environment, to monitoring the flight itself, a central data monitoring network is required to process the information and ensure all areas are running optimally and safely.
These systems are designed to take the information from all sensors, apply compensating factors for the low temperature and low density of the surrounding environment, and processes the data via an analog-to-digital convertor before displaying it to the pilots.
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