Four people, including a National Institutes of Health scientist and two other Montgomery County residents, were killed yesterday in the crash of a single-engine private plane shortly after takeoff from an airport in Westminster, Md.

The pilot of the plane, a Baltimore County man, reportedly was attempting to ferry the Montgomery residents to the Montgomery County Airpark in Gaithersburg. The three had flown to the Carroll County airport in their own plane, but it was unable to take off for the return trip, according to an airport employee.

The three county residents were identified as Eberhard G. Trams, 56, of 4715 Morgan Dr., Chevy Chase; John Edred Don Carlos III, 20, of 5301 Mohican Rd., Bethesda, and Elaine Isabell Dion, 20, of 5204 Little Falls Dr., Chevy Chase.

Trams, a PhD biochemist and pharmacologist,was a section chief in the National Institute of Neurological and Communicative Disorders and Stroke. A native of Berlin and a naturalized citizen, he flew in the German Luftwaffe during World War II, according to his NIH branch chief. Dr. Roscoe O. Brady described him as a "very good scientist" nearing the peak of his career who was "really getting some very good information on the biochemistry of manic depressive illness."

Witnesses said the plane, piloted by Francis L. Fenwick, 33, of Glyndon, took a long time to climb into the air. When it finally did, its engine sputtered. A minute or two later, the Piper Cherokee struck trees and crashed.

The cause of the 2:15 p.m. crash and of the difficulties with the plane left behind could not be learned immediately.