alert phase

Also found in: Acronyms.

alert phase (ALERFA)

A phase that begins when apprehension exists about the safety of an aircraft and its occupants, after the uncertainty phase, and a communications search has failed to reveal any news of the aircraft; or an aircraft has been cleared to land and fails to land within 5 min after the estimated time of landing and communication has not been reestablished with the aircraft; or information has been received that indicates that the operating efficiency of the aircraft has been impaired but not to the extent that a forced landing is likely. The code word used to indicate this phase is ALERFA.
References in periodicals archive ?
I began to gain this experience and develop these processes when the 1-338th Training Support Battalion sent me to assist the 829th Engineer Team during the alert phase of its preparation for OIF 1 in February 2003.
The WHO designation of a pandemic alert Phase 6 reflects the fact that there are now ongoing community-level outbreaks in multiple parts of world.
In response to a question on pandemic alert phase change, Dr Chan explained that the definition of WHOs influenza preparedness phases was developed against backdrop of H5N1 avian flu.