Air Data The Collection
Air Data systems provide accurate information on quantities such as pressure, altitude, vertical speed, calibrated airspeed, true airspeed, Mach number, static air temperature and air density ratio. This information is essential for the pilot to fly the aircraft safely and is required by a number of key avionic subsystems which enable the pilot to carry out a mission.
The static and pitot-static probes connect via pipes to transducers that convert the sensed air-pressures into signals that can be processed by the Air Data Computer. The computer outputs may feed directly to Instruments (e.g. Altimeter and IAS) or other systems (e.g. Head Up Display and Flight Management).
Air Data Sensors can take many forms such as: probes that extend well forward of the aircraft (to avoid aerodynamic interference or shock waves); side-mounted orifices (for stealth reasons many military aircraft use flush ports); side mounted swivelling probes that sense angle of attack; gimballed probes (allowing helicopters to sense left-right and fore-aft airspeed components, including zero when hovering).