A Swearingen SA226-AT Merlin IVA cargo aircraft, registered EC-GFK, experienced a landing accident at Gerona-Costa Brava Airport (GRO) on a local training flight. The aircraft executed two landings, followed by two touch-and-goes, and then circled for a full stop landing. The undercarriage was not deployed, and the aircraft landed gear-up. A left engine caught fire, which was quickly extinguished. The incident was caused by the crew’s failure to activate the deployment lever for the landing gear, coupled with inadequate documentation regarding flight tasks and timing.A Swearingen SA226-AT Merlin IVA cargo aircraft, registered EC-GFK, experienced a landing accident at Gerona-Costa Brava Airport (GRO) on a local training flight. The aircraft executed two landings, followed by two touch-and-goes, and then circled for a full stop landing. The undercarriage was not deployed, and the aircraft landed gear-up. A left engine caught fire, which was quickly extinguished. The incident was caused by the crew’s failure to activate the deployment lever for the landing gear, coupled with inadequate documentation regarding flight tasks and timing.