An air data module is a component of the

navigation system A navigation system is a computing system that aids in navigation. Navigation systems may be entirely on board the vehicle or vessel that the system is controlling (for example, on the ship's bridge) or located elsewhere, making use of radio or othe ...

. Each unit converts pneumatic (air pressure) information from a

pitot tube A pitot ( ) tube (pitot probe) measures fluid flow velocity. It was invented by a French engineer, Henri Pitot, in the early 18th century, and was modified to its modern form in the mid-19th century by a French scientist, Henry Darcy. It ...

or a

static port A pitot-static system is a system of pressure-sensitive instruments that is most often used in aviation to determine an aircraft's airspeed, Mach number, altitude, and altitude trend. A pitot-static system generally consists of a pitot tube, a ...

into numerical information which is sent on a data bus. This pressure information is received and processed by the Air Data Reference (ADR) component of the

Air Data Inertial Reference Unit An Air Data Inertial Reference Unit (ADIRU) is a key component of the integrated Air Data Inertial Reference System (ADIRS), which supplies air data (airspeed, angle of attack and altitude) and inertial reference (position and attitude) information ...

(ADIRU). This processed information is then sent to one or more display management computers that present information on the cockpit's

primary flight display A primary flight display or PFD is a modern aircraft instrument dedicated to flight information. Much like multi-function displays, primary flight displays are built around a Liquid-crystal display or CRT display device. Representations of ol ...

. Airspeed information is also sent to the flight computers and other electronics, including the autoflight subsystem (e.g. flight management and guidance system).

Construction

The air data module is a gas pressure sensor which converts mechanical forces created by gas pressure into digital signals that can be carried to the air data reference unit. ADMs generally have a maintenance bus and communication bus, and a connector on the housing for a pressurized gas line that is connected to the pitot tube or static ports. The maintenance bus can be

EIA-485 RS-485, also known as TIA-485(-A) or EIA-485, is a standard defining the electrical characteristics of drivers and receivers for use in serial communications systems. Electrical signaling is balanced, and multipoint systems are supported. The s ...

and the communication bus can be

ARINC 429 ARINC 429, "Mark33 Digital Information Transfer System (DITS)," is also known as the Aeronautical Radio INC. (ARINC) technical standard for the predominant avionics data bus used on most higher-end commercial and transport aircraft. It defines the ...

References

Avionics Aircraft instruments Air navigation Navigational equipment {{Aviation-stub