Revision 4 - December 17,1998 Ryan TCAD 9900 Series Page 3-1
SECTION III
OPERATION
3.1 GENERAL
TCAD uses transponder replies to compute bearing (9900B), relative altitude and range
from nearby Mode C or Mode S-equipped aircraft. Non-Mode C aircraft provide range
information only.
Relative altitude information is derived from decoding the altitude replies from nearby
aircraft, and comparing the data with the encoded altitude information from the host
aircraft. Range information is determined from the arrival amplitude of the transponder
signal. TCAD displays the range in indicated Nautical Miles (iNM). Refer to the Pilot's
Handbook (P/N 32-2302) for TCAD Limits. Bearing is derived from dual directional
antennas and associated receivers.
The 9900 Series Display uses 20 LED cells to communicate alphanumeric information.
Audible and visual alerts are provided. See Figure 3-1 for special symbols used, and
Figures 3-2 and 3-3 for basic Display information.
A tone or voice, and an optional annunciator output (for an annunciator lamp) is used to
call attention to a detected threat that has penetrated the Air Traffic Shield. Additionally,
when the Altitude Alert is engaged, a distinctive short tone is generated to call attention to
either arrival at a target altitude, or an altitude deviation.
3.2 AUDIO & VISUAL ALERT
One visual and four audible alerts are used by TCAD:
TRAFFIC DETECTION A single tone or voice alert for traffic detected inside
the selected Air Traffic Shield. When traffic is
detected close to the host aircraft, the tones become
repetitive. See the Pilot's Handbook.
ALTITUDE ALERT A non-repetitive tone for the Altitude Alert function.
PERFORMANCE MONITOR A non-repetitive tone indicating a detected TCAD
malfunction.
VISUAL ALERT An auxiliary output connected to an annunciator
lamp, providing a visual alert to displayed traffic.