• All-digital, including computation, transmission and display
• Programmable analog outputs support a wide variety of user systems
• Highly reliable ADC because of low-power CMOS parts and a rugged solid-state piezoresistive sensor
• ARINC 429 capability
• Enhanced fault isolation through the use of internal diagnostics and nonvolatile memory
• Reduced cost of ownership by increased availability of the system
• RVSM-compliant system

The Collins ADS-85( )/86( ) Air Data System senses, computes and displays all parameters associated with aircraft movement through the atmosphere. It meets the demanding performance requirements of high-performance business jets and regional aircraft. It also provides for optimal performance of the flight guidance system in all vertical modes and can also display all air data parameters essential to flight. The ADS-85A/86A is currently certified to comply with the Reduced Vertical Separation Minimum (RVSM) requirements.

The system is all digital from the Air Data Computer (ADC) to the air data displays on the instruments. It provides digital outputs for use by the APS-65/85 Autopilot, AHS-85 Attitude Heading Reference System, EFIS-85/86 Electronic Flight Instrument System and other interfacing aircraft systems.

The ADC-85( ) is a form, fit and functional replacement for the ADC-81/82( ).

The ADS-85( )/86( ) comes from a long lineage of proven performance. The ADS-85/86/850 family of solid-state air data systems is certified on over a dozen different aircraft with more than 10,000 system deliveries. Before introducing the ADS-85( )/86( ) family, Rockwell Collins sold more than 2,500 of the highly successful ADS-80/81/82 systems. This systems standard equipment on many business, regional and air transport aircraft. The central air data system brings air transport-class capabilities and accuracy to business aircraft.

The ADC-85( )/86( ) uses a totally digital design approach. It digitizes pressure and temperature information from the sensors, then digitally computes and transmits the data throughout the system.

Transmissions to other on-board systems are also digital. This unique digital design offers reduced size, weight and power consumption; continuous monitoring of all functions and internal diagnostics; increased system integrity and simplified installation.

The system can be tailored to fit specific customer requirements. The ADC receives pneumatic inputs from the pitot/static system and electrical signals from the aircraft outside temperature probe. It uses these to compute altitude, airspeed, Mach and temperature parameters. In turn this information provides outputs for the flight control system, navigation system, aircraft control system and ATC transponder, as well as for the primary air data instruments. The use of digital display instruments reduces the maze of pneumatic plumbing behind the instrument panel to only those lines needed for the standby instruments.

The ADS-85A/86A far exceeds the FAA Technical Standard Order (TSO) accuracy requirements that include display instrument errors. In addition, when included with aircraft air data components, the Collins ADS complies with RVSM requirements.

Features of the system include:

• Monitoring of all essential functions
• On-board fault isolation
• Solid-state piezoresistive pressure transducers
• Digital computational and display accuracy
• Solid-state synchronization circuits
• Low power consumption components
• Internal diagnostics and nonvolatile memory
• 28 V DC operation
• Servo driven speed reminder bugs
• RVSM compliance

Computed and available parameters from the ADC-85( )/86( ) are:

• Indicated airspeed
• True airspeed
• Vertical speed
• Vmo/Mmo
• Static air temperature
• Total air temperature
• Preselected altitude
• Overspeed warning contacts
• ADC valid contacts
• Uncorrected pressure altitude
• Barometric corrected altitude

The computer provides digital outputs to the flight control system, air data instruments, attitude heading reference system, electronic flight control displays, aircraft subsystems and navigation systems.

It continuously monitors altitude and airspeed computation channels. To increase assurance of normal operation, the pilot can activate a computer self-test on the ground before takeoff. An overspeed warning test function is also provided.

The pressure transducer in the ADC-85/86is a piezoresistive solid-state pressure transducer. Rockwell Collins has many years experience in solid-state transducer technology and has supplied more than 9,000 solid-state sensors. The sensors reduce the power input and weight of the ADC-85( )/86( ) and significantly increase reliability.

The sensor element itself is a tiny silicon chip with piezoresistive elements diffused into its surface. Pressure applied across the chip strains the piezoresistive elements and the resistance of each element changes. The sensor converts these changes to a digital signal which is then processed by a computer. The computer calculates the absolute static pressure and differential pressure between the static and pitot ports of the aircraft and converts them to the familiar air data quantities such as altitude and airspeed. Collins piezoresistive sensors are highly accurate, reliable and durable.

Altitude information displayed on the altimeter is consistent with the operation of the autopilot in altitude hold because the same pressure sensing source supplies both systems. Airspeed is also consistent between the airspeed instrument and the autopilot airspeed hold mode.