TM 1-1520-218-10
3C-215
A/B
Figure 3C-155. Preventive RA Operational Situation
(2) If the threat aircraft maneuvers to cause a
new conflict before the RA clears, a corrective RA may
be issued, overriding the preventive RA.
j. No Bearing Messages. When an intruder is
detected, but no bearing can be determined for the
aircraft, a no-bearing message is displayed in slot 6
(and slot 7 if two or more aircraft produce this
situation; highest priority will be displayed first). A No
Bearing Message is displayed. Refer to Figure
3C-156. The yellow TA indicates that the intruder is
causing a traffic alert. The 1.2 indicates a distance to
the intruder of 1.2 miles. The 00 indicates that the
intruder is level at your own altitude. An RA No
Bearing Message, displayed in red, would be
interpreted the same.
k. Clear of Conflict. When the range of an
intruder responsible for causing an RA begins to
increase, its conflict is considered to be resolved. If
more than one intruder is involved in an RA, all
conflicts must be resolved before the clear-of-conflict
message will be issued. When this occurs, "Clear of
Conflict" will be annunciated.
l.
Failure Indications.
(1) Figure 3C-157 shows a TCAS flag,
indicating failure of the TCAS and no range ring is
displayed. Normal vertical speed operation is not
affected. If the display is a result of a self-test being
completed, the aural message, "TCAS System Test
Fail" will be annunciated.
(2) Figure 3C-158 shows an RA and a V/S
flag, indicating failure of the vertical speed indicator. If
the vertical speed function of the indicator has failed, it
can display no vertical speed commands, thus no RA
maneuvers can be commanded. The RA flag is also
displayed because of this.
