What is a preflight check indicator for Halon 1211?

A preflight check indicator for Halon 1211 being identified as "the arrow on green" indicates that the fire extinguisher is fully charged and ready for use. The gauge typically features a colored indicator that displays the pressure level of the extinguisher. When the arrow points to the green section, it signifies that the extinguisher is in proper working condition, which is crucial for ensuring the safety of passengers and crew in an emergency situation.

It is essential for flight crews to regularly check extinguishers before a flight, and a reading in the green ensures that the Halon 1211 can effectively suppress fires if needed. Regularly confirming that this indicator is in the green zone helps in adhering to safety protocols and maintaining the operational readiness of emergency equipment on board.