TEGUCIGALPA, HONDURAS, JUNE 16 -- Nicaragua's Sandinista government today claimed that a rebel aircraft it shot down yesterday was piloted by the chief of the rebel air force and that he and two crewmen were injured when the plane crash-landed inside Honduras.

A spokesman for the Nicaraguan Embassy here, Juan Jose Membreno, identified the casualties as Juan Gomez, a former colonel in Nicaragua's National Guard who now commands the rebel air force; his son, also named Juan Gomez; and a rebel named Aurelio Carasco.

{In the Nicaraguan capital of Managua, a Sandinista spokeswoman identified the younger Gomez as the plane's copilot and Carasco as the gunner, Associated Press reported. The spokeswoman attributed the information to "intelligence sources."}

Membreno identified the aircraft as a twin-engine Beechcraft Baron and said it was on a reconnaissance flight, but also had attacked a Sandinista military post with rockets. He said the Sandinista Army hit the plane with ground fire at about 2:30 p.m. near Cerro el Doradito, about six miles from the Honduran border in northern Nicaragua's Nueva Segovia Province. The aircraft went down about four miles inside Honduras at Cerro el Tigre, he said.

According to a source who is in contact with the Nicaraguan rebels, called contras, only two persons were in the plane, Gomez and his son, and they were injured when the aircraft made a "controlled crash" in Honduran territory. There was no immediate word on how seriously they were injured.

The source said the plane had been dropping anti-Sandinista pamphlets over the Nicaraguan city of Esteli before it was "disabled" by Sandinista ground fire and had to limp back to Honduras.

{Honduran military authorities said the plane's pilot and copilot had been captured and were being investigated, United Press International reported. The officials denied the plane had taken off from Honduras.}

In Managua, a Defense Ministry spokesman said the rebel plane did not damage Sandinista installations or injure government troops.

There was no formal comment on the incident from the rebel press office here. A contra spokesman in Miami confirmed that the plane belonged to the Nicaraguan Democratic Force, the main rebel army, but insisted that "it was neither armed nor carried ammunition." The spokesman said he had no further information on the incident.

A European diplomat said the contras were not known to possess any aircraft capable of firing rockets. He said the contra air force consisted of a few transport aircraft used to drop supplies to rebels inside Nicaragua and some small planes used to ferry officials. Few of the planes are believed to be airworthy.

The incident came as Central American leaders engaged in a flurry of diplomatic activity aimed at rescheduling a summit conference to discuss a peace plan for the region.

The meeting of the presidents of Honduras, Guatemala, Nicaragua, El Salvador and Costa Rica had been scheduled for June 25-26. It was suddenly postponed after Salvadoran President Jose Napoleon Duarte objected last week to the cancellation of a preparatory foreign ministers' meeting and said he was going on a European tour.

In an effort to resolve the issue, Guatemalan President Vinicio Cerezo arrived here today and met with Honduran President Jose Azcona. The presidents told reporters afterward that they had set a "tentative date" of Aug. 6-7 for a summit in Guatemala, to be preceded by three foreign ministers' meetings in Honduras, El Salvador and Nicaragua.

Azcona and Cerezo said that Duarte had accepted the new date "in principle" and that they would now consult with Costa Rican President Oscar Arias Sanchez and Nicaraguan President Daniel Ortega.

Both Cerezo and Azcona denied that the United States had exerted pressure to postpone the summit because of reported U.S. fears that the five Central American states would agree to a peace plan that would fail to meet American security interests.