What Is a ‘Reliever’ Field?

Answer: Per 49 USC § 47102(23), a reliever airport is a facility designated by the FAAto relieve congestion at a commercial service airport (where the airlines are) by providing more GA access to the community. 

A reliever can be towered or nontowered and will likely have an eclectic mix of corporate jets, light piston twins, and training aircraft. 

As for when an airliner uses a "reliever field," it has more to do with the length and weight-bearing capability of the runway and what the airline's procedures allow the crews to use. If the runway is too short,such as less than 5,000 feet long,or has a weight limit in excess of the weight of the aircraft, an airline—or any other aircraft that needs more length and strength—isn’t going to be able to use that particular runway.

Do you have a question about aviation that's been bugging you? Ask us anything you've ever wanted to know about aviation. Our experts in general aviation, flight training, aircraft, avionics, and more may attempt to answer your question in a future article.