TPU-67A part numbers 066-01146-1111 and 066-01146-1211 include the Change 7 enhancements for MOPS (Minimum Operation Performance Standards).

When an omnidirectional antenna is used as the bottom antenna in a CAS-67A TCAS II installation, the 3 unused bottom antenna coax connectors on the TPU-67A processor must be connected to 50 ohm terminations.

TCAS II is a system used for detecting and tracking aircraft in the area of an aircraft. TCAS interrogates transponders in other aircraft and analyzes the replies to determine range, bearing, and relative altitude (if reporting) of the intruder aircraft. When the TCAS II processor determines that a potential collision hazard exists, it will issue visual and audio advisories to the pilot/copilot for appropriate vertical avoidance maneuvers. TCAS is not able to detect aircraft without an operating ATCRBS transponder (operating in Mode A and C) or a Mode S transponder.

TCAS II utilizes two types of cockpit displays, Resolution Advisory (RA) and Traffic Advisory (TA) display. The RA is incorporated into the vertical speed indicator (VSI). With illuminating red and green arcs around the dial, the VSI displays the required rate, or limitation of climb or descent, to avoid a collision. The TA display shows the intruding aircraft’s relative position and altitude with a trend arrow to indicate if it is climbing or descending greater than 500 feet per minute. The TA display may be presented on compatible weather radar indicator or MFD, dedicated TCAS display or a TA/VSI display. The TA display uses symbols and colors to identify the relative threat of each intruder. Supplementing the displays, TCAS II provides appropriate synthesized voice announcements.

Many avionics systems require a configuration or setup process. This process is required to interface certain avionics systems to other systems in the aircraft that will be inputting or outputting information to and from these systems. Some examples of systems that require a configuration or setup process include:

Autopilot
EFIS
GPS
EGPWS
EHSI
RADAR
TAWS
TCAS


In addition, most newer technology or solid state systems require configuration via computer interface of some type. A qualified avionics technician should always refer to the appropriate manufacturer's installation manual for complete information and instructions.

Yes, the TPU-67A -1111 incorporates software improvements to meet European ACAS II requirements (TCAS Change 7). The -1111 complies with TSO C119b and meets requirements specified in DO-185A (TCAS Change 7).

Yes, the TPU-67A -1211 incorporates all features currently available for the TPU-67A. That is, the TPU-67A -1211 includes the software improvements for TCAS Change 7 (European ACAS II requirements). The TPU-67A -1211 is also capable of accepting a dual attitude & heading input. The -1211 complies with TSO C119b and meets requirements specified in DO-185A (TCAS Change 7).

To verify proper operation of the CAS-67A TCAS II System, a pretest setup, self-test, ground test and ramp test must be performed. The following ground test equipment is required for these tests:

- Portable computer with TPU-67A field diagnostics program
- TCAS Ramp Test Set
- Mode S Transponder Ramp Test Set
- Pitot Static Test Set
- Radio Altimeter Test Set

For more information, refer to the CAS-67A TCAS II System Installation Manual.

Utilizing more than one antenna to improve the quality and reliability of radio signal is called antenna diversity.

Heavy and/or faster aircraft utilize top and bottom antenna configurations to eliminate the possibility of signal blind spots caused by shadowing. Lighter, slower general aviation aircraft typically only have 1 antenna and do not require antenna diversity. Although not completely uniform, the transmission pattern of a typical antenna provides adequate radiation above and below in relation to most GA aircraft even when the antenna is on the bottom of the aircraft.