AOG Cost Estimator

A complete AOG cost includes: (1) lost charter revenue for the affected days, (2) crew standby or deadhead costs if crew cannot be productively deployed, (3) positioning flight costs to move the aircraft to a maintenance facility or back to base, (4) actual maintenance and parts costs, and (5) any customer compensation, accommodation, or alternative transport arranged. Many operators underestimate the total because they track only the maintenance invoice.

Part 135 operators carry the airworthiness responsibility under 14 CFR 135.25. An AOG event that grounds a revenue aircraft triggers cascading costs: no revenue comes in, but fixed crew costs continue, and customer relationships are at risk. Operators with a single aircraft are especially exposed. AOG cost quantification helps justify maintenance reserve funding, spare-parts stocking, and wet-lease agreements as backup capacity.

A positioning (or ferry) flight is a non-revenue flight to reposition the aircraft for maintenance or to return it to base after repair. Under Part 135 operations, a ferry flight with inoperable equipment may require a special flight permit (14 CFR 21.197) if the aircraft does not meet its type certificate limitations. The cost of the positioning flight — fuel, crew time, landing fees — should be included in the total AOG calculation.

Common mitigation strategies include: maintaining a wet-lease or interchange agreement as backup capacity, stocking high-frequency consumable parts, negotiating AOG priority with maintenance facilities, carrying maintenance reserve funding in escrow, and selecting aircraft types with strong regional MRO support. The best AOG management is not the response plan — it is the pre-emptive maintenance program that prevents unscheduled events.