Flying vehicles have come a long way since Orville and Wilbur first demonstrated the viability of flight at Kitty Hawk, NC in 1903. Although a marvel of its time, the Wright Flyer contained no electronics. Today, aerospace vehicles are comprised of thousands of PCBAs and electronic devices, many of which are sensors.

Sensors are critical to the operation of today’s advanced aircraft. For example, the Air Force’s F-35 jet relies on sensors for monitoring system parameters, including fuel, air temperature, oxygen, oil, positioning, and pressure. All of these are important variables, and optimizing the types of pressure sensors used for aerospace applications is often critical for mission success.

Types of Pressure Sensors for Aerospace Applications

Whether for commercial airliners, defense aircraft, or spacecraft, pressure sensors are utilized for virtually all applications—both internal and external—as shown below.

Common Pressure Sensor Usage for Commercial Applications

• ➣ Total air pressure
• ➣ Cabin air pressure
• ➣ Hydraulics pump pressure
• ➣ Hydraulics differential pressure
• ➣ Engine differential pressure
• ➣ Engine bleed pressure
• ➣ Landing gear pressure
• ➣ Pressure switches

Common Pressure Sensor Usage for Defense Applications

• ➣ Air pressure
• ➣ Fuel pressure
• ➣ Hydraulics differential pressure
• ➣ Engine differential pressure
• ➣ Engine bleed pressure
• ➣ Landing gear pressure
• ➣ Pressure switches
• ➣ Weapons pressure

Common Pressure Sensor Usage for Space Applications

• ➣ Oxidizer pressure
• ➣ Fuel tank pressure
• ➣ Pump inlet pressure
• ➣ Pump outlet pressure
• ➣ Gearbox oil pressure
• ➣ Helium tank pressure
• ➣ Thrust chamber pressure
• ➣ Hydraulic accumulator pressure

As these examples clearly indicate, failure of the various types of pressure sensors for aerospace applications could lead to severe consequences ranging from significant vehicle damage or destruction to fatalities of flight crews or passengers. Avoiding these potential outcomes is critical; therefore, it is imperative that your design includes the best aerospace sensors.

Choosing the Best Pressure Sensors for Aerospace Design

When choosing a pressure sensor for your aerospace application, it’s important to follow a set paradigm, such as the one outlined below.

Criteria for Selecting the Best Aerospace Pressure Sensors

• Know the environmental challenges for sensor deployment.
  The first thing to consider are the hazards of the deployment environment and how they will affect the pressure exerted on the aerospace vehicle’s exterior or interior.

• Know or determine a reference pressure.
  The reference pressure falls within the range of membrane deformation for the sensor type and material. This is the value of comparison to the forced deformation of the membrane that corresponds to pressure reading and/or calculation.
• Determine which type of pressure you are measuring.
  • Differential
    For a differential pressure sensor, the difference between the deformation from two inputs is measured and used to determine the pressure.
• • Absolute
    For absolute sensors, the input is under vacuum and its deformation represents the actual pressure value.

• • Relative
    The ambient or environmental pressure is the reference and the deformation indicates the relative change in pressure.

• Employ best practices for pressure-tolerant electronics selection.

• • Consider the environment, material quality, and component resilience during your selection process. For very harsh environment deployments such as space, due diligence requires adequate testing that may include Destructive Physical Analysis (PDA).