A 77-year-old man was taken in serious condition to a hospital Monday after the pilot of a small plane apparently performed an emergency landing at a construction site in Kapolei.

The Honolulu Fire Department received a 911 call at 12:49 p.m., and the first of 13 units arrived at the scene near 91-469 Ka­polei Kai St. to find a small plane leaking fuel.

“The aircraft was not on fire and the two occupants were conscious and awake,” Malcolm Medrano, the department’s on-duty public information officer, said in an email.

One of the occupants climbed out of the plane on his own, while the other needed assistance from the cockpit and required medical attention from Honolulu Emergency Services, Medrano said.

“The HFD corralled the leaking aviation fuel that was coming from the aircraft’s wing and controlled it from getting into any storm drains or waterways,” he said.

The Federal Aviation Administration said the pilot was reporting mechanical issues with the single-engine Diamond DA40 before the hard landing.

The State Airport Firefighting Rescue unit from the Kalaeloa Airport arrived on the scene to assist, along with officers from the Honolulu Police Department. The FAA and the aircraft owner also arrived to accept custody and responsibility at the scene, officials said.

The National Transportation Safety Board will investigate the incident, along with the FAA.