Collision Alarm (Cpa, Tcpa); How To Set The Cpa And Tcpa Ranges; How To Acknowledge The Tt Collision Alarm - Furuno FAR-2218 Operator's Manual

3.15

Collision Alarm (CPA, TCPA)

This radar calculates CPA and TCPA by using own ship and relative target positions.
The TT continuously monitors the pre-
dicted range at the Closest Point of Ap-
proach (CPA) and predicted time to
CPA (TCPA) of each TT. When the
predicted CPA of any TT becomes
smaller than a preset CPA range and
its predicted TCPA less than a preset
TCPA limit, the audio alarm sounds
and "TT DANGER OF COLLISION"
appears (in red, flashing) in the Alert
Box. In addition, the symbol of the of-
fending TT is red and flashes together with its vector.
This feature, when used correctly, helps prevent the risk of collision by alerting you to
threatening targets. It is important that GAIN, A/C SEA, A/C RAIN and other radar con-
trols are properly adjusted.
CPA and TCPA ranges must be set up properly taking into consideration the size, ton-
nage, speed, turning performance and other characteristics of own ship.
The reference point for CPA and TCPA calculation can be selected from antenna po-
sition or conning position. For further details, see section 1.50.
3.15.1

How to set the CPA and TCPA ranges

CPA and TCPA ranges can be adjusted from the ap-
propriate indication in the [TT] box.
1. Left-click the [CPA/TCPA] indication to activate
the feature.
2. Place the cursor on the indication you wish to
adjust.
3. Left-click, or spin the scrollwheel, to adjust the settings as required. The settings
options are outlined in the table below.
Indication Method
CPA Left-click
Scrollwheel
TCPA Left-click
Scrollwheel
3.15.2

How to acknowledge the TT collision alarm

Press the ALARM ACK key on the control unit, or select the [ALERT] box with the
trackball then left-click to acknowledge the alarm and silence the buzzer. The alert "TT
DANGER OF COLLISION" remains in the Alert Box until the dangerous situation is
gone or you intentionally terminate target tracking. The symbol and vector stop flash-
ing and are displayed in a solid red color.
0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 5.0, 6.0 (NM)
0.1 to 20; 0 to 10 in 0.1 NM increments, 1 NM increments thereafter
1, 2, 3, 4, 5, 6, 12, 15 (minutes)
1 to 60 minutes in 1-minute increments
3. TARGET TRACKING (TT)
CAUTION
CPA/TCPA Alarm
The CPA and TCPA alarm feature should
never be relied upon as the sole means for
detecting the risk of collision.The navigator
is not relieved of the responsibility to keep
visual lookout for avoiding collisions,
whether or not the radar or other plotting
aid is in use.
Left-click here to activate
CPA/TCPA settings.
Settings options
CPA setting
TCPA setting
3-21