AMA
AMA refers to Area Minimum Altitude — the lowest altitude that will provide a minimum vertical clearance above all obstacles within a defined area. In Canadian IFR operations, AMA values are published on IFR charts and provide a safety floor for off-airway operations.
AMA Clearance Margins
AMA values include a 1,000 ft obstacle clearance buffer in non-mountainous areas and 2,000 ft in designated mountainous terrain. This margin is built in — maintaining or exceeding the AMA guarantees obstacle clearance within that sector.
When AMA Applies
AMA is used when an aircraft operates off published airways under IFR. Before descending below AMA, a positive position fix must be established (GPS, DME, radar, visual) and descent conducted with confirmed terrain clearance.
AMA vs. MEA vs. MOCA
- AMA: Off-airway sector minimum; guarantees obstacle clearance within the geographic sector
- MEA: On-airway minimum; guarantees obstacle clearance AND navaid reception along the route
- MOCA: On-airway minimum; guarantees obstacle clearance but only navaid reception within 22 NM of the facility
Related Terms
See also: Area Minimum Altitude, MEA, MOCA.