Can We Technicians Get Some Love ?

[TCAS 4 DUMMIES]

I see some Major airline threds and a few other threads for gen chat .... I would like to see one for the People behind the sceen who make the Magic happen =) maybe we can even exchange ideas .. owww .. and concerns ahhh

 

[TCAS 4 DUMMIES]

The NTSB wants the FAA to inform all pilots who use transponders or TCAS units to become familiar with their current annunciations.

U.S. Federal Aviation Regulations require TCAS to be installed on all Turbine powered airplanes of more than 33,000 pounds maximum certificated takeoff weight operating under 14 CFR parts 121, 125, and 129 and on all airplanes with 10 to 30 seats that are operated under parts 121, 129.

P.S. withing the next few years all TTR-920 TCAS will be phazed out and 921 / 4000 will be the only thing in the sky due to software upgrades.

 

[TCAS 4 DUMMIES]

JULY 1 2002.
Bashkirian Airlines Flight 2937.


The two aircraft were flying at 36,000 (FL360) feet on a collision course. Despite being over Germany, the airspace was controlled from Zürich, Switzerland by the private Swiss airspace control company Skyguide.

The air traffic controller handling the airspace, Peter Nielsen, was working two workstations at the same time and did not realise the danger facing the two aircraft until less than a minute before the accident. At that time he contacted Flight 2937, instructing the pilot to descend by a thousand feet to avoid collision with crossing traffic (Flight 611). Seconds after the Russian crew initiated the descent, however, their Traffic Collision Avoidance System (TCAS) instructed them to climb, while at about the same time the TCAS on Flight 611 instructed the pilots of that aircraft to descend. Had both aircraft followed those automated instructions, it is likely that the collision would not have occurred.

Flight 611's pilots on the Boeing jet initially followed the TCAS instructions and initiated a descent, but could not immediately inform the controller due to the fact that he was dealing with Flight 2937. About eight seconds before the collision, Flight 611's descent rate was about 2400 feet per minute, not as rapid as the 2500-3000 ft/min range advised by TCAS. The Russian pilot on the Tupolev disregarded the TCAS instruction to climb and instead began to descend, as instructed by the controller, thus both planes were now descending. During this descent the Russian pilot went below his assigned flight level by about 33 metres (110 ft), and also changed his magnetic bearing once again, by another ten degrees.

Unaware of the TCAS-issued alerts, Nielsen repeated his instruction to Flight 2937 to descend, giving the Tupolev crew incorrect information as to the position of the other plane. Maintenance work was being carried out on the main radar system, which meant that the controllers were forced to use a slower system. The Flight 2937 crew tried to locate the DHL flight visually in the dark, losing reaction time.

The aircraft collided at almost a right angle at 34,890 feet, with the Boeing's vertical stabilizer slicing completely through Flight 2937's fuselage just ahead of the Tupolev's wings. The Tupolev exploded and broke into several pieces, scattering wreckage over a wide area. The crippled Boeing, now with 80% of its vertical stabilizer lost, struggled for a further seven kilometres (4.3 miles) before crashing into a wooded area close to the village of Taisersdorf at a 70 degree downward angle; each engine ended up several hundred metres away from the main wreckage, and the tail section was torn from the fuselage by trees just before impact. All 69 people on the Tupolev, and the two on board the Boeing, lost their life.







Other factors in the crash


One air traffic controller, Peter Nielsen of ACC Zurich, was controlling the airspace through which the aircraft were transitioning. The only other controller on duty was resting in another room for the night. This was against the regulations, but had been a common practice for years and was known and tolerated by management. Due to maintenance work Nielsen had a stand-by controller and system manager on call; Nielsen was unaware of this or he chose not to use them in order to avoid dangerous boredom.[1]

In addition, a ground based optical collision warning system which would have alerted the controller to imminent collisions early had been switched off for maintenance; Nielsen was unaware of this. There still was an aural STCA warning system, which released a warning addressed to workstation RE SUED at 21:35:00 (32 seconds before the collision); this warning was not heard by anyone present at that time, although no error in this system could be found in a subsequent technical audit; if this audible warning is turned on or not, is not logged technically. Even if Nielsen had heard this warning, he might have misinterpreted it until the next radar update 12 seconds later became visible or until the TCAS descent notice by the DHL crew came in; at that time finding a useful resolution order by the air traffic controller is difficult to impossible.[1]

The main phone lines at Skyguide was also down as part of the maintenance work, and the backup line was defective. This prevented adjacent air traffic controllers at Karlsruhe from phoning in a warning.

In the minutes before the accident, Nielsen was occupied with an Airbus on a delayed Aero Lloyd Flight 1137 approaching Friedrichshafen Airport.[1] Handling two workstations at once, Nielsen struggled with the malfunctioning phone system that he was trying to use to call the Friedrichshafen airport to announce the approaching Aero Lloyd. Due to these distractions he did not spot the danger until about a minute before impact. Had he ordered the Russian plane to descend earlier, the aircraft would have been separated and their collision avoidance systems would not have issued instructions. When Nielsen realised that the situation (the multiple factors in two workstations) was overwhelming, it was too late to summon assistance.

Switzerland commented in the "Publication of deviating statements" section of the official report of the German federal investigators that the Tupolev was about 33 metres below the flight level ordered by the Swiss controller, and still descending at 1900 feet per minute, and that in spite of the false information given (position and phraseology) by the Swiss controller the TCAS advisories would have been useful if obeyed immediately.

The Russian Federation countered in the same section of the official report that the Russian pilots were unable to obey the TCAS advisory to climb; the advisory was given when they were already at 35500 feet while the controller wrongfully stated there was conflicting traffic above them at 36000 feet. Also, the controller gave the wrong position of the DHL plane (2 o'clock instead of the actual 10 o'clock), and the DHL crew had a "real possibility" to avoid a collision since they were able to hear the conversation between the Russian crew and the controller.

The change of magnetic bearing of the Russian aircraft by cumulatively 20 degrees (from 254 to 274) during the upcoming conflict is not assessed in the official report.

:::::::::::::::::::::: NOT TRYING TO DEPRESS ANYONE::::::::::::::::: its just the nature of the beast and i the Best damn job GOD WILLING to keep you all safe in the air.


Peace b with you...

 

[hardfault]

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