The Tupolev 154 airliner was involved in a midair collision with a Boeing 757 cargo plane in 2002 over Lake Constance, near the German border with Switzerland. All 69 people on board the plane flying from the Urals, including 45 children, were killed in the resultant crash.
Speaking Tuesday at a hearing in a Buelach district court, in the canton of Zurich, Prosecutor Bernhard Hecht accused staff of private Swiss air traffic control agency company Skyguide, which had been supervising the flights, of a negligent attitude to their responsibilities, but said they could not have foreseen the consequences.
The collision occurred at 11:35 p.m. local time (9:35 p.m. GMT) on July 1, 2002, with Swiss national Peter Nielsen as the only controller on duty at that point.
The eight Skyguide personnel who are on trial in the case denied any personal involvement, saying Nielsen, slain in 2004 by a Russian who lost his family in the accident, was the only one to blame.
But Hecht contested this suggestion, arguing that the company's top management must also be held responsible for having too few controllers on duty. At the time of the tragedy, Nielsen was in the control room alone, monitoring 15 flights, while his colleague was on a break.
Many insiders have suggested that the excessive workload could have prevented Nielsen from alerting the Tupolev and the Boeing crews to the potential danger early enough for them to avoid the collision.
Russian national Vitaly Kaloyev, whose wife and two children died in the crash, stabbed Nielsen to death in February 2004. In 2005, he was sentenced to eight years in a high security prison after a Swiss court found him guilty of murder.
At Tuesday's court hearing, Hecht also dismissed suggestions that errors by the Russian crew could have been a factor in the crash.
An independent Austrian expert who gave evidence to the Buelach court earlier this week also said the Tu-154 pilots had been correct to follow the human controller's instructions rather than those given by the on-board Traffic Collision Avoidance System (TCAS).
Nielsen instructed the Tu-154 crew to descend as soon as he realized the plane was on a collision course with the Boeing 757. The Russians initiated the descent, continuing even after being alerted by the TCAS system to climb. The Boeing 757 crew began descending at about the same time, on instructions from their TCAS.
The Skyguide hearings, which began on May 15, will continue through May 31, but the verdict is not expected to be handed down until July.
Russians who lost their loved ones in the crash believe, however, that the sentence recommended by Swiss prosecutors is not harsh enough.
"We find it hard to understand why prosecutors are recommending such a lenient punishment," one of the relatives, Zulfat Khamatov, said.
He accused Switzerland's judiciary of a double standard approach to the Russian air crash case, with Kaloyev locked up for eight years after a snap trial and the Skyguide staff facing suspended sentences of just over a year following proceedings launched five years after the tragedy.
