How Pressure and Temperature Sensors Improve Aircraft Safety

Aircraft sensors are responsible for transforming physical phenomena into electrical signals that aircraft computers and pilots can interpret for monitoring purposes. When values exceed safety thresholds, sensors help trigger alerts or automatic adjustments through the Aircraft Condition Monitoring System (ACMS) or Electronic Centralized Aircraft Monitoring (ECAM) system, allowing crews to quickly take corrective action. In particular, pressure and temperature sensors are variants that play some of the most essential roles in identifying early signs of failure. In this blog, we will explore the basic design and functionality of pressure and temperature sensors in aviation, illustrating how these components safeguard various aircraft systems.

Pressure Sensors

Aircraft pressure sensors detect changes in physical force applied to a sensing element, then convert those changes into electrical signals that can be interpreted by aircraft systems. These sensors can function in two primary ways:

• Strain Gauge Technology: This type of pressure sensor uses a thin, flexible material that changes its electrical resistance when stretched or compressed by pressure.
• Capacitive Diaphragm Technology: Pressure sensors with this design measure changes in the spacing between two conductive plates (or a diaphragm and a plate) as pressure causes them to deflect. The resulting change in capacitance is used to determine pressure levels, offering high sensitivity.

By assisting in identifying potential issues such as leaks, overpressure conditions, or component failure before they escalate, pressure sensors are commonly used in:

• Cabin pressurization systems to ensure a stable internal environment and prevent structural fatigue
• Environmental control systems, where they monitor air duct pressure to support regulated airflow for air conditioning and anti-icing operations
• Hydraulic systems used for landing gear, flight controls, and brakes to track fluid pressure
• Fuel systems to monitor fuel line pressure and tank pressurization, safeguarding delivery efficiency
• Engine performance monitoring, particularly for detecting oil and compressor pressure

Design Variations

In addition to differences in strain gauge and capacitive diaphragm measuring methods, pressure sensors are available in configurations like:

• Absolute Pressure Sensors: Absolute variants measure pressure relative to a fixed vacuum reference, being commonly used in altimetry and cabin pressure monitoring.
• Differential Pressure Sensors: These pressure sensors measure the difference between two pressure points for monitoring filter conditions, airflow, or fuel flow differentials.
• Gauge Pressure Sensors: Measuring pressure relative to ambient atmospheric conditions, gauge pressure sensors are commonly used in hydraulic and fuel systems to monitor line pressure under varying altitude and load conditions.

Furthermore, sensors can also be tailored to specific pressure levels, with low-pressure variants being used for tasks in ECS and cabin systems, while high-pressure sensors are employed in hydraulics and engine applications. Depending on integration needs, sensors may also provide analog outputs like voltage or current for direct gauge interface, or instead create digital outputs for flight computers and data buses.

Temperature Sensors

Aircraft temperature sensors detect and convert temperature changes into electrical signals, primarily relying on two technologies:

• Thermocouples: These sensors consist of two dissimilar metals joined at one end, which generate a small voltage that corresponds to the temperature they are exposed to. Thermocouples can withstand extreme heat and provide rapid readings, serving turbine sections and exhaust systems well.
• Resistance Temperature Detectors (RTDs): RTDs measure temperature by detecting changes in a material’s electrical resistance as it heats or cools. Platinum is commonly used because its resistance changes in a consistent, predictable way. Known for their high accuracy, RTDs are ideal for applications requiring precise thermal monitoring, such as in fuel systems and avionics cooling.

With this being said, temperature sensors are deployed across various aircraft systems where thermal changes can indicate risk or performance degradation. They assist in:

• Engine monitoring, tracking exhaust gas temperatures (EGT), turbine inlet temperatures (TIT), and oil temperatures to detect overheating or combustion anomalies
• Airframe ice detection and anti-icing system control, being placed in wings, pitot tubes, and engine inlets
• Thermal management of avionics and electrical systems
• Fuel temperature monitoring
• Cabin and environmental temperature regulation

Design Variations

Besides their method of measurement, some temperature sensors are specifically designed to function in the frigid temperatures found in high-altitude fuel systems, while others can withstand extreme heat in areas like turbine inlet and exhaust zones.

Combined Sensor Technologies and Redundancy

To reduce system complexity, many aircraft operators opt to use integrated sensor modules that combine pressure and temperature sensing in a single housing. These multifunctional sensors are especially useful in propulsion and environmental systems, where both parameters must be tracked simultaneously.

In conjunction, some aircraft safety systems may also feature multiple sensors that monitor the same parameter. This approach ensures that a failure in one sensor does not result in a loss of critical data, as well as enables an aircraft’s monitoring system to cross-reference outputs for fault detection.

Turn to a Reliable Source for Aircraft Sensors

In summary, aircraft safety depends on proactive monitoring for tasks ranging from maintaining hydraulic pressure to detecting engine overheating, which temperature and pressure sensors serve well. To help them continue to perform such roles, securing replacements from a certified source is imperative. ASAP Components, a website operated by leading distributor ASAP Semiconductor, offers a streamlined procurement solution for aviation-grade sensors and more.

This resource features an extensive catalog of high-performance aviation components, each sourced from verified manufacturers and suppliers. Moreover, with competitive pricing, fast global delivery options, and tailored solutions, professionals can count on us to fulfill even the most demanding operational requirements with confidence. With this being said, do not hesitate to explore our selection and get in touch with our experts regarding your aviation sensor needs and beyond.