|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||0601 To 1200|
|Locale Reference||airport : ord|
|Altitude||msl bound lower : 8500|
msl bound upper : 9000
|Controlling Facilities||tracon : ord|
|Operator||common carrier : air carrier|
|Make Model Name||Heavy Transport, Low Wing, 4 Turbojet Eng|
|Flight Phase||descent other|
|Route In Use||arrival other|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Experience||flight time last 90 days : 260|
flight time total : 25000
flight time type : 2400
|Function||flight crew : first officer|
|Qualification||pilot : instrument|
pilot : commercial
|Anomaly||altitude deviation : overshoot|
non adherence : clearance
other anomaly other
|Independent Detector||other flight crewa|
|Resolutory Action||flight crew : returned to intended course or assigned course|
|Primary Problem||Flight Crew Human Performance|
|Air Traffic Incident||Pilot Deviation|
My company is evaluating a collision threat device. Basically, by using a special antenna which can disseminate a bearing it can display symbols upon a screen which represent other aircraft in the vicinity of ownership. Using the returns of altitude reporting transponders and a special computer it can calculate flight paths and give visual and aural warnings if these flight paths would come closer than an agreed minimum. And, quite frankly, this experience is terrifying. All of us feel we keep the best look out that we can, are perhaps aware it is not as good as it should be, but feel that we would see a threat in time. This device displays all the transponders it can find within the vicinity of ownership, and even before it tells you what it thinks you ought to do, the bare display of traffic is a tremendous shock. One can see ATC's responsibilities and how it deals with them. In this instance, the copilot, who was flying, had been cleared to level off at 9000', and was just about to do so when the collision avoidance system gave a traffic alert. We were so busy trying to find the conflicting traffic, and were confused by the additional aural and visual warnings that the aircraft dipped about 300' or so below the cleared flight level (this was not the cause of the warning, which turned out to be an arrival climbing away from us and behind us). We recovered at once, but again we had broken the old rule, 'somebody has to fly the aeroplane.' callback conversation with reporter revealed the following: reporter explained that TCAS system they are testing gives all targets within 20 mi, but cuts off any 2500' above or below ownership. Computer then figures flight paths and comes up with which way to evade. Problem is that alarm right now is to close to altitude alert signal sound so if happen to get more than 1 warning at time could miss one. Thinks once crews are used to it and problems worked out it will be great.
Original NASA ASRS Text
Title: ACR HVT WITH TCAS SYSTEM INSTALLED FOR EVALUATION INCURRED ALT EXCURSION BECAUSE OF ATTENTION TO TCAS ALERT.
Narrative: MY COMPANY IS EVALUATING A COLLISION THREAT DEVICE. BASICALLY, BY USING A SPECIAL ANTENNA WHICH CAN DISSEMINATE A BEARING IT CAN DISPLAY SYMBOLS UPON A SCREEN WHICH REPRESENT OTHER ACFT IN THE VICINITY OF OWNERSHIP. USING THE RETURNS OF ALT RPTING TRANSPONDERS AND A SPECIAL COMPUTER IT CAN CALCULATE FLT PATHS AND GIVE VISUAL AND AURAL WARNINGS IF THESE FLT PATHS WOULD COME CLOSER THAN AN AGREED MINIMUM. AND, QUITE FRANKLY, THIS EXPERIENCE IS TERRIFYING. ALL OF US FEEL WE KEEP THE BEST LOOK OUT THAT WE CAN, ARE PERHAPS AWARE IT IS NOT AS GOOD AS IT SHOULD BE, BUT FEEL THAT WE WOULD SEE A THREAT IN TIME. THIS DEVICE DISPLAYS ALL THE TRANSPONDERS IT CAN FIND WITHIN THE VICINITY OF OWNERSHIP, AND EVEN BEFORE IT TELLS YOU WHAT IT THINKS YOU OUGHT TO DO, THE BARE DISPLAY OF TFC IS A TREMENDOUS SHOCK. ONE CAN SEE ATC'S RESPONSIBILITIES AND HOW IT DEALS WITH THEM. IN THIS INSTANCE, THE COPLT, WHO WAS FLYING, HAD BEEN CLRED TO LEVEL OFF AT 9000', AND WAS JUST ABOUT TO DO SO WHEN THE COLLISION AVOIDANCE SYS GAVE A TFC ALERT. WE WERE SO BUSY TRYING TO FIND THE CONFLICTING TFC, AND WERE CONFUSED BY THE ADDITIONAL AURAL AND VISUAL WARNINGS THAT THE ACFT DIPPED ABOUT 300' OR SO BELOW THE CLRED FLT LEVEL (THIS WAS NOT THE CAUSE OF THE WARNING, WHICH TURNED OUT TO BE AN ARR CLBING AWAY FROM US AND BEHIND US). WE RECOVERED AT ONCE, BUT AGAIN WE HAD BROKEN THE OLD RULE, 'SOMEBODY HAS TO FLY THE AEROPLANE.' CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING: RPTR EXPLAINED THAT TCAS SYS THEY ARE TESTING GIVES ALL TARGETS WITHIN 20 MI, BUT CUTS OFF ANY 2500' ABOVE OR BELOW OWNERSHIP. COMPUTER THEN FIGURES FLT PATHS AND COMES UP WITH WHICH WAY TO EVADE. PROB IS THAT ALARM RIGHT NOW IS TO CLOSE TO ALT ALERT SIGNAL SOUND SO IF HAPPEN TO GET MORE THAN 1 WARNING AT TIME COULD MISS ONE. THINKS ONCE CREWS ARE USED TO IT AND PROBS WORKED OUT IT WILL BE GREAT.
Data retrieved from NASA's ASRS site as of August 2007 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.