A helicopter plunged into the Mediterranean Sea off the coast of Netanya yesterday, taking the lives of four people - an airline owner, a pilot for El Al and another with Arkia, and a Cypriot tourist.

The victims were named as Yoav Tamir, an owner of Tamir Airways; El Al pilot Ran Lapid, who was flying the copter for Tamir; and Arkia pilot Hadar Shavit, who used to fly for Tamir. The tourist from Cyprus was a businessman in the airline industry who had links with Tamir from private flights the company had made there.

The Robinson R44 model helicopter, which holds four passengers, had lifted off from Tel Aviv's Sde Dov airport. Eyal Amrani, a lifeguard working at Netanya's Sironit Beach, said he heard an unusual noise before the aircraft hit the water. He said he and another lifeguard immediately called police and the Magen David Adom rescue service and then ran into the water.

"When we reached the site of the crash, we found two bodies and pulled them to the coast," Amrani said. "When we understood that there were two additional casualties, we dove back out and found two more bodies strapped into their seats in the helicopter."

Initial investigation into the crash points to a technical malfunction, possibly rotor failure. The probe will examine the possibility of human error, though Lapid was viewed as an experienced helicopter pilot. He had regularly flown El Al Boeing 737 planes as well as private airplanes; he also served as a helicopter pilot in military reserve duty.

Parts of the aircraft retrieved from the sea will be sent for laboratory tests, and investigators will visit the Herzliya facility that maintained the copter.

Yesterday's incident was not the first time a civilian aircraft has plunged into the sea. In a similar accident nine years ago, two passengers were killed after the propeller of a smaller Robinson model, the R22, fell apart. Ten copters of the larger R44 model are currently in airline and private use in Israel.

A guest at the Carmel Hotel in Netanya who saw the crash said, "I saw the helicopter flying north of the hotel, about 500 meters from the beach. I focused on the helicopter and saw it slowly descend toward the water. Suddenly it flipped 90 degrees, the propeller hit the water and broke off, and the helicopter dove into the water. I was in shock."