View Full Version : Midair crash, at odds..

27th Aug 2002, 04:06
Pilot error is blamed as the experts question failure of failsafe system
PILOT error was being blamed last night for the Lake Constance air disaster, as it emerged that the Russian plane failed to respond to air traffic control orders to descend.

Aviation experts said it was unlikely the patchwork nature of Europe's air traffic control zones was the problem, but said language difficulties could have played a part.

A recent rule change on how close planes are allowed to fly to each other was also likely to come under the spotlight, although officials insisted that it had no bearing on the accident.

Both aircraft were equipped with a sophisticated collision-avoidance system and crash investigators will want to know why this did not prevent the accident.

Swiss air traffic control said it had been in charge of the planes, both flying at around 36,000ft. Anton Maag, chief of the control tower at Zurich, said the first descent order was given to the Bashkirian Airlines Tupolev 154 plane about a minute before the impact - a time window that "wasn't irresponsible, but fairly tight".

He said the Russian plane began to decrease altitude only after a second request. At the same time, the DHL cargo plane's automatic collision warning system issued an order to descend, and pilots are obliged to immediately follow these instructions, Mr Maag said.

As both planes descended they collided in one of the worst air accidents in Germany's history. Mr Maag said the air traffic controller in charge at the time was working alone as his partner took a break because of the light air traffic.

"There are two mysteries," Patrick Herr, Swiss air traffic control spokesman, said later.

"Firstly, why the Tupolev pilot didn't react straight away. And secondly, why the automatic warning system of the Boeing 757 also gave a descent order." Swiss air traffic control initially said it had given the Russian plane about two minutes' warning and the pilot responded after the third request.

It revised its account after the German agency for air accident investigations said the Russian pilot was given only about 50 seconds and reacted after the second warning.

Russian aviation authorities angrily rejected pilot error as a possible cause, saying the Tupolev pilot had years of experience and spoke English well, so he would have understood instructions to descend.

Bashkirian Airlines also denied that the Tupolev crew had made any mistakes.

"My version is that the (air) traffic controllers are to blame," Nikolai Odegov, the airline's director, said in Moscow.


BERLIN - The pilot of a Russian passenger jet that collided in mid-air with a DHL freight plane responded immediately to orders from a Swiss air-traffic controller to descend, despite conflicting warnings from his onboard computer, German investigators said Monday.
Germany's air-accident investigation agency had previously said the pilot of the Bashkirian Airlines Tu-154 only responded to a second order to descend from Swiss air-traffic control.

The information led to speculation the Russian pilot was unsure whether to obey the air-traffic controller, or his Traffic alert and Collision Avoidance System, or TCAS, which told him to climb.

Western experts have said pilots are always taught TCAS orders take precedence, but Russian aviation officials have insisted their pilots are told to obey air-traffic control orders in case of conflict.

The DHL International Boeing 757-200 pilot followed his TCAS command to descend, but did not alert ground control that he was bringing the plane down until 13 seconds before impact, the report confirmed.

The two planes collided over a strip of southern Germany controlled by Swiss towers on July 1, killing 71 people.

It had been unclear from the flight-data recorder exactly when the Russian plane began its descent into the DHL jet's path, but more detailed information was uncovered in examination of the Tu-154's TCAS computer, said Frank Goeldner, a spokesperson for the German agency, which is in charge of the investigation.

The report said both aircraft were equipped with the same TCAS systems, and neither malfunctioned. It noted that "both operators had provided training programs for TCAS and the crews had completed the corresponding training."

Goeldner said investigators are still looking into who the Russian crew was trained to obey. Accident investigations usually take about a year to complete, Goeldner said.

The crash killed 69 people on the Russian plane, including 45 pupils heading for a Spanish beach vacation, and the two DHL pilots.

Investigators have so far focused on the role of Zurich controllers, who had command of the planes even though they were in German airspace. A lone controller was on duty while a colleague took a break, a collision-warning system was down for maintenance and the phones were being repaired.

Swiss prosecutors have launched a criminal investigation to see whether charges of negligent homicide are warranted. That investigation will not proceed until German authorities have finished their report, Swiss air-traffic control spokesperson Patrick Herr said. The air-traffic controller who was on duty was suspended shortly after the crash.


Don't Look Now
27th Aug 2002, 04:36
What's new about this?

27th Aug 2002, 05:24
perhaps a new thread?