Aircraft clock with gps time updating
In addition to the two TCAS antennas, two antennas are also required for the Mode S transponder.One antenna is mounted on the top of the aircraft while the other is mounted on the bottom.
The next step beyond identifying potential collisions is automatically negotiating a mutual avoidance manoeuver (currently, manoeuvers are restricted to changes in altitude and modification of climb/sink rates) between the two (or more) conflicting aircraft.These avoidance manoeuvers are communicated to the flight crew by a cockpit display and by synthesized voice instructions.A protected volume of airspace surrounds each TCAS equipped aircraft.The implementation of TCAS added a safety barrier to help prevent mid-air collisions.However, further study, refinements, training and regulatory measures were still required, because the limitations and misuse of the system still resulted in other incidents and fatal accidents, which include: The airline industry has been working with the Air Transport Association of America (ATA) since 1955 toward a collision avoidance system.The antennas used by TCAS II include a directional antenna that is mounted on the top of the aircraft and either an omnidirectional or a directional antenna mounted on the bottom of the aircraft.
Most installations use the optional directional antenna on the bottom of the aircraft.
Although the flight crew operated the system, the evaluation was primarily for the purpose of data collection and its correlation with flight crew and observer observation and response.
Later versions of TCAS II manufactured by Bendix/King Air Transport Avionics Division were installed and approved on United Airlines airplanes in early 1988.
ACAS / TCAS is based on secondary surveillance radar (SSR) transponder signals, but operates independently of ground-based equipment to provide advice to the pilot on potential conflicting aircraft.
In modern glass cockpit aircraft, the TCAS display may be integrated in the Navigation Display (ND) or Electronic Horizontal Situation Indicator (EHSI); in older glass cockpit aircraft and those with mechanical instrumentation, such an integrated TCAS display may replace the mechanical Vertical Speed Indicator (which indicates the rate with which the aircraft is descending or climbing).
The operational evaluation programs continued through 1988 to validate the operational suitability of the systems TCAS involves communication between all aircraft equipped with an appropriate transponder (provided the transponder is enabled and set up properly).