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. Last Updated: 07/27/2016

Swiss Turned Off Air Warning System

UEBERLINGEN, Germany -- Swiss authorities said a collision-warning system was out of service in the Zurich tower when it took control of a Bashkirian Airlines Tu-154 and a cargo jet shortly before they collided at 10,500 meters, killing 71 people, mostly children headed for a summer vacation.

As an international investigation began, Swiss air traffic control also said one of two controllers in the tower took a break during the maintenance operation on the warning system -- which alerts controllers to the danger of a collision.

Patrick Herr, a spokesman for Swiss air traffic control, said Zurich airport's collision warning system, which is meant to alert air traffic controllers of a danger of collision about one and a half minutes before projected impact was down Monday night for checks on its software. The maintenance is carried out on a routine basis at quiet traffic times.

He refused to speculate whether the system might have helped prevent the two aircraft smashing into each other.

"There seems to have been an extraordinary combination of extremely unlucky coincidences," Herr said.

Officials at Skyguide, the Swiss air traffic control company, gave conflicting accounts on whether the controller's break was authorized.

Anton Maag, chief of the Zurich airport control tower, said Skyguide rules forbid leaving a lone controller on duty without the aid of the warning system. But one of his aides, Philipp Seiler, later said that this rule does not apply at night.

Russian investigators sent to Germany by President Vladimir Putin toured the debris field Wednesday and met local investigators in the nearby town of Friedrichshafen.

Salvage crews were expected to move pieces of the shattered, twisted wreckage to the Friedrichshafen airport soon so investigators can examine them.

The chartered Bashkirian Airlines jetliner and a Boeing 757 cargo plane collided over Germany, leaving a 30 kilometer-wide debris field near Ueberlingen, a vacation spot set in rolling hills and forests on Lake Constance across from Switzerland. Five U.S. investigators were also expected on the scene.

Police spokesman Michael Kuhn said nine more bodies were found after the search resumed at dawn, bringing the total to 37.

Russian investigators concentrated on a large section of the Tu-154's fuselage, which lay about 500 meters from where three engines from the tail of the aircraft were embedded in a charred corner of a golden barley field.

Investigators believe as many as 20 more bodies of passengers and crew may be in the fuselage, still strapped into their seats, but have not yet been able to get inside to know for sure, Kuhn said.

Swiss officials were already facing criticism for not giving the Russian pilot enough time to lower the Tu-154 out of the way of the cargo jet. The Swiss insist the 50-second warning should have been sufficient, but a German pilot representative said pilots usually count on five to 10 minutes warning.

Initially, Swiss air traffic control said it gave the Tu-154 about two minutes' warning and that the pilot responded after a third request. But the Swiss revised their account after German officials began describing the tighter time scenario.

The Russian pilot heeded the command to descend after a second warning. But the cargo jet was equipped with a radar collision avoidance system that told its pilots to descend as well.

The result was a fiery collision over Lake Constance, shared by Germany and Switzerland, and flaming chunks of wreckage raining down on farms and forests. No one on the ground was hurt.

Two pilots died aboard the cargo plane operated by the DHL International delivery service. Their bodies were among those recovered in the first day of searching.

Investigators from Germany's aviation authority were to begin analyzing information Wednesday from the planes' flight data recorders and cockpit voice recorders.

Bashkirian Airlines has defended its pilots as fluent in English with thousands of flying hours and experience on overseas missions and pointed the finger at the controllers.

Compounding the problems for the Swiss -- which pride themselves for their strict safety standards -- details emerged Wednesday of a government-commissioned report which said Skyguide's radar system fell below European safety standards in several key respects.

The report from the Swiss Aircraft Accident Investigation Bureau, completed late last month and published on the Internet, was based on three near misses between 1998 and 2000. It said big differences between radar readings issued by Geneva and Zurich centers called into question the quality and reliability of the entire system. Skyguide fell short of demands by the Europe-wide body Eurocontrol that all radar data be stamped with "universal time."

This risked discrepancies of several seconds between Swiss readings and those of neighboring countries. That could mean the location of a plane on the radar screens was out by up to 500 meters. The report said there were also deficiencies in the quality of the radar equipment used by Skyguide to trace plane movements.

An air traffic control spokesman, Philipp Seiler, refused to comment in detail on the findings but said Skyguide was in the process of introducing changes to meet the recommendations.

Switzerland lies at the heart of Europe and the airspace around the Zurich hub is heavily congested. At peak traffic times, air traffic controllers routinely make decisions about necessary altitude changes within tight time schedules.

Investigators on Wednesday hoped to be able to interview the air traffic controller, who hasn't been named. He was treated for shock Tuesday and not in a fit state to be questioned. He has been described as an experienced staff member.