safety alert

An alert issued to an aircraft under the control of ATC (air traffic control) if in the controller’s opinion the aircraft’s altitude is unsafe with respect to the terrain or an obstruction, or it is in an unsafe proximity to other aircraft. When feasible, the controller will offer the pilot an alternative course of action. If the pilot confirms that he or she is taking the necessary corrective action, the controller may discontinue giving further instructions. Once this alert is issued, it is solely the pilot’s prerogative to determine what course of action, if any, to take. This procedure is intended for use in situations where aircraft safety is in question. The issuance of a safety alert cannot be mandated, but it can be expected on a reasonable, although intermittent, basis. The two types of alert are the terrain/obstruction alert and the aircraft conflict/mode C intruder alert.