Members of the Israel Defense Force's elite 669 search-and-rescue unit on Wednesday  collected body parts of all six IAF servicemen and the Romanian liasion officer who lost their lives when their CH-53 helicopter crashed on Monday in Romania's Carpathian Mountains during a joint military exercise.

The search-and-rescue crew also collected pieces of the crashed helicopter, which will aid the investigation into the cause of the accident.

The IDF and the Romanian army plan to hold a memorial ceremony on Thursday afternoon at the military base from which the doomed helicopter took off. Afterward, the Israeli search-and-rescue unit will return to Israel, where identification of the bodies of the fallen Israeli servicemen will continue.

Three helicopters carrying teams from the 669 unit arrived on Wednesday at the site of Monday's crash.

The IDF teams established two mountainside bases close to the crash site, before beginning the search for debris and body parts, to be transferred to a central collection point some 2.5 kilometers away.

Romanian rescuers, meanwhile, informed the Israelis that they had recovered body parts and transferred them to a hospital in the nearby city of Brasov. The IDF teams also set up a communications center at a nearby Romanian air base with a direct video link to commanders in Israel.

Wednesday's landing was the first at the crash site, high in the Carpathian Mountains, which until now had been inaccessible to search teams.

The rescue aircraft, which took off from a nearby Romanian base at around 6:00 AM local time, were carrying army crash investigators, as well as IDF rabbis.

A Romanian official said on Tuesday that all seven bodies had been located. All six Israelis were experienced members of the Israel Air Force. The Romanian was a liaison officer who was accompanying the Israeli crew on the flight.

Air force investigators suspect that human error stemming from poor visibility caused the fatal crash.

Officially the air force says that all possibilities are being investigated, including the option that the helicopter experienced a technical problem that led to the crash.

The helicopter's black box was discovered at the site at approximately midnight on Tuesday, and was transferred to Israel for inspection.

The air force's chief of staff, Brig. Gen. Nimrod Sheffer, said Tuesday it was still early to comment on the cause of the disaster.

But the decision by IAF chief Major General Ido Nehushtan not to ground the CH-53 fleet, common when there are concerns that a crash occurred for technical reasons, suggests that human error is believed to be the cause.

A former IAF chief, Major General (res.) Avihu Ben-Nun, gave a similar assessment in an interview with Army Radio on Tuesday.

Nehushtan has appointed Brigadier General (res.) Shlomo Mashiach, an experienced helicopter pilot, to head the investigation. Also in the team are members of the force's air accident investigation unit. Mashiach and his team traveled to Romania on Tuesday and are at the scene of the crash.

The initial findings and information provided by the pilot of the second helicopter flying in formation allow a general picture of the accident to be formed.

The two helicopters were on a routine exercise, part of the joint training drill with the Romanian air force. The six represented two sets of crew, each comprising two pilots and a flight engineer. The plan was to allow the crews to switch and practice flying during a relatively complex training flight, without having to return to base to change crews.