warning systems

A traffic advisory prediction will annunciate when an aircraft is within conflict airspace in:

25–45 seconds — A Traffic Advisory (TA) predicts that another aircraft will enter TCAS conflict airspace in 25 to 45 seconds. A TA is intended to help the crew establish visual contact with the traffic. [Ref: Chapter 15 — Warning Systems — 15.20.13]

Proximate traffic shows on the TCAS display when the aircraft is within:

6 miles AND 1,200 ft vertically — Proximate traffic is traffic that is neither an RA nor a TA, but is within six miles and 1,200 feet vertically. It is shown as a filled white diamond when displayed. [Ref: Chapter 15 — Warning Systems — 15.20.14]

A TRAFFIC message displayed in amber means:

Traffic Advisory (TA) — An amber TRAFFIC message indicates that a Traffic Advisory is occurring. The associated TA traffic symbol is a filled amber circle. [Ref: Chapter 15 — Warning Systems — 15.20.14–15]

A TRAFFIC message displayed in red means:

Resolution Advisory (RA) — A red TRAFFIC message indicates that a Resolution Advisory is occurring. An RA predicts entry into TCAS conflict airspace within approximately 20 to 30 seconds and provides PFD vertical guidance. [Ref: Chapter 15 — Warning Systems — 15.20.13–15]

GPWS red PULL UP on both PFDs shows projected impact in:

20–30 seconds — The red GPWS look-ahead warning corresponds to a projected terrain or obstacle impact in approximately 20 to 30 seconds. This is the warning-level alert, requiring immediate attention/action in accordance with the applicable procedure. [Ref: Chapter 15 — Warning Systems — 15.20.19]

An amber CAUTION obstacle indication on both NDs shows projected impact in:

40–60 seconds — The amber look-ahead obstacle/terrain caution is generated when projected impact is approximately 40 to 60 seconds away. It is the caution-level alert, earlier than the red warning envelope. [Ref: Chapter 15 — Warning Systems — 15.20.20]

All TCAS RAs are inhibited below approximately:

1,000 ft radio altitude — During approach, all TCAS Resolution Advisories are inhibited at approximately 1,000 feet radio altitude. TCAS switches to TA-only operation and TA ONLY is displayed on the ND. [Ref: Chapter 15 — Warning Systems — 15.20.40]

All TCAS DESCEND RAs are inhibited below approximately:

1,100 ft radio altitude — During approach, TCAS DESCEND RAs are inhibited at approximately 1,100 feet radio altitude. This inhibit occurs before the approximately 1,000-foot point at which all RAs are inhibited. [Ref: Chapter 15 — Warning Systems — 15.20.40]

All TCAS INCREASE DESCENT RAs are inhibited below approximately what altitude?

1,500 ft radio altitude — During approach, TCAS INCREASE DESCENT RAs are inhibited at approximately 1,500 feet radio altitude. This is the highest of the three descent-related TCAS inhibit thresholds shown in the FCOM table: INCREASE DESCENT about 1,500 ft, DESCEND about 1,100 ft, and all RAs about 1,000 ft. [Ref: Chapter 15 — Warning Systems — 15.20.39–40]