Flight Control

Pressure sensing is fundamental to flight control because airspeed, altitude, and vertical speed are derived from air pressure rather than measured directly from motion or position. The pitot-static system compares total pressure from the airstream with ambient static pressure to determine airspeed, while static pressure provides barometric altitude and vertical speed. Pressure-based angle-of-attack systems use differential measurements from dedicated sensing ports. Together, these measurements provide the air data that cockpit instruments and automatic flight-control systems need throughout every phase of flight.

Reliable air-data systems must detect small pressure changes at low airspeeds, respond rapidly to changing flight conditions, and reject disturbances from vibration, turbulence, and aerodynamic buffeting. Temperature variations and aircraft maneuvers add further complexity, as changes in bank, climb, descent, pitch, and roll continually affect sensor orientation and operating conditions. Dynamic pressure can range from a few pascals at low airspeed to several kilopascals during cruise, while absolute static pressure decreases from approximately 101 kPa at sea level to 18 kPa at 40,000 feet.

Superior Sensor Technology’s ND Series supports flight-control applications with low-pressure-differential models for airspeed and pressure-based angle-of-attack measurement, as well as absolute-pressure models for barometric altitude. With a 2.25-millisecond update rate, the series keeps pressure data current. Optional advanced digital filtering helps prevent vibration and aerodynamic noise from obscuring true flight conditions. For particularly orientation-sensitive measurements, the ND210 offers 0.25 pascal of position sensitivity, helping prevent aircraft maneuvers from appearing as false pressure changes.

Recommended Sensors

Common Device Features: 3.3V supply
Long-Term Stability is measured after first 12 months
Short-Term Error Band (STEB) is measured over 24 hours, after auto-zero

Common Specifications

Flight Control FAQ

How do pressure sensors determine airspeed and altitude?

An aircraft’s pitot-static system measures total pressure via a forward-facing pitot tube and ambient static pressure via ports on the aircraft’s exterior. The difference between total and static pressure is dynamic pressure, which the flight system uses to calculate airspeed. Because static pressure decreases predictably with altitude, it also provides the basis for calculating barometric altitude. The rate of change of static pressure provides vertical-speed information. Together, these measurements provide essential air data to cockpit instruments, air-data computers, and automatic flight-control systems throughout takeoff, climb, cruise, descent, and landing.

How is pressure used to measure angle of attack?

Pressure-based angle-of-attack systems compare differential pressure across dedicated sensing ports or probes. As the aircraft’s orientation relative to the airflow changes, the pressure relationship between these ports also changes. The flight system converts this differential measurement into angle-of-attack data that can support stall awareness, flight-envelope protection, and automatic flight-control functions. Because these pressure differences can be small, especially at lower airspeeds, the sensors must provide high resolution, low noise, and a stable zero.

What types of pressure sensors are used for flight control?

Flight-control applications commonly require both differential- and absolute-pressure measurements. Differential-pressure sensors measure the difference between pitot and static sources to determine airspeed and can also support pressure-based angle-of-attack measurement. Absolute-pressure sensors measure static atmospheric pressure for barometric-altitude and vertical-speed calculations. The ND Series includes low-pressure differential models for airspeed and angle-of-attack applications, as well as absolute-pressure models for altitude sensing. Multi-Range™ technology allows differential models to support up to seven factory-calibrated pressure ranges with the same hardware, while absolute-pressure models provide fixed ranges for specific barometric requirements.

Why do response time and digital filtering matter in flight-control applications?

Flight conditions can change rapidly during maneuvers, turbulence, takeoff, and landing. Pressure sensors must update quickly enough to ensure that cockpit instruments and automatic flight-control systems operate on current air-data measurements. The ND Series provides a 2.25-millisecond update rate to support these dynamic applications. At the same time, engine and propeller vibration, aerodynamic buffeting, and turbulence can introduce noise into the pressure signal. Programmable digital filtering attenuates these disturbances before they reach the sensor output. A selectable bandwidth lets engineers balance noise reduction with the response speed the flight-control system requires.

How do temperature and aircraft attitude affect pressure measurements?

Temperature changes can affect a pressure sensor’s offset, span, and overall measurement accuracy. The relevant conditions depend on the installation location, since temperatures inside an avionics enclosure or a protected area of the airframe can differ substantially from the outside air temperature. The ND Series is temperature-compensated from −20°C to +85°C, helping maintain consistent performance across its specified operating environment. Aircraft attitude can also affect sensitive low-pressure measurements. As an aircraft banks, climbs, descends, or encounters turbulence, gravity acts on the sensing element from different directions, producing an apparent pressure change. For particularly orientation-sensitive applications, the ND210 provides positional sensitivity within 0.25 pascal, helping reduce attitude-related errors in critical air-data measurements.