Change of gauge (aviation)

In aviation, "change of gauge" refers to the substitution of one type or size of aircraft for another on a scheduled flight. This typically involves using an aircraft with a different number of seats or cargo capacity.

Changes of gauge can be temporary or permanent. A temporary change might occur due to maintenance requirements, unexpected high demand for a particular flight, or operational constraints at the origin or destination airport. A permanent change of gauge would involve a scheduled shift in the type of aircraft used on a specific route.

Airlines might implement a change of gauge for a variety of reasons:

• Matching Capacity to Demand: Airlines frequently adjust the size of the aircraft used on a route to better align the number of seats offered with the anticipated passenger demand.

• Operational Efficiency: Using a smaller aircraft on a route with consistently low load factors can improve fuel efficiency and reduce operational costs. Conversely, larger aircraft might be deployed to accommodate high-demand periods.

• Maintenance Scheduling: A change of gauge might be necessary to substitute an aircraft undergoing scheduled maintenance with an available replacement.

• Network Optimization: Airlines often adjust aircraft assignments across their network to optimize resource allocation and route profitability.

• Airport Restrictions: Certain airports have restrictions on the size or type of aircraft that can operate there, potentially necessitating a change of gauge for specific flights.

Passengers may experience changes of gauge in the form of different seating arrangements, in-flight entertainment options, or overall cabin comfort compared to what was initially anticipated. Airlines generally attempt to minimize disruptions to passengers when implementing a change of gauge.