 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
Light transport aircraft climbing to FL210 had TCASII RA. Controller told flight crew to descend back to FL200 'due to traffic,' then they received a climb RA as intruder aircraft showed 400 ft below them.
| Attributes | |
| ACN | 398332 |
| Time | |
| Date | 199804 |
| Day | Wed |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : iad |
| State Reference | DC |
| Altitude | msl bound lower : 20000 msl bound upper : 20600 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zdc |
| Operator | general aviation : corporate |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | Part 91 |
| Navigation In Use | Other Other |
| Flight Phase | climbout : intermediate altitude |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Any Unknown or Unlisted Aircraft Manufacturer |
| Operating Under FAR Part | other : unknown |
| Flight Phase | descent other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | Other |
| Function | flight crew : first officer |
| Qualification | pilot : atp pilot : commercial |
| Experience | flight time last 90 days : 150 flight time total : 14000 flight time type : 3500 |
| ASRS Report | 398332 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | conflict : nmac other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : took evasive action other |
| Consequence | Other |
| Miss Distance | horizontal : 0 vertical : 400 |
| Supplementary | |
| Primary Problem | ATC Human Performance |
| Air Traffic Incident | Operational Error |
Narrative:
We were in the clear, climbing to FL210. Passing through FL201 we received a traffic alert on the TCASII and it popped up on the multi-function display. The target was showing 1400 ft above us and was almost overlaid on top of our position. At FL205 we were told by the controller to descend back down to FL200. No urgency was stressed, just 'due to traffic.' passing through FL206 and while initiating a descent back down to FL200, we received an RA of 'climb, climb.' the traffic was now overlaid on top of us and now showed 400 ft below us. We never saw the other aircraft or heard center issue any type of clearance to them. Obviously, it was a very confusing 15 seconds going from climb to descend to climb! The controller was dealing with data that was being updated very slowly while our TCASII showed a more realistic picture. Our first reaction on the TA was 'where is he?' with the traffic almost on top of us on the multi-function display, and with the overlaying of graphical data, it made it hard to interpret the data rapidly. With the RA we knew where we stood. I just wish it would have come quicker. Obviously, human error somewhere in the ATC system or the other aircraft contributed to this situation. I was also under the mistaken impression that an alarm in the ATC computer would alert the controller when 2 jets were going to occupy the same airspace and in the past our TCASII had given us considerably more warning than it did on this occasion. Evidently, the vertical closure rates were too high for either system to handle after the human error had been made. I would like to see both the ARTCC and TCASII system updated further. In the meantime, wear a rabbit's foot!
Original NASA ASRS Text
Title: LTT ACFT CLBING TO FL210 HAD TCASII RA. CTLR TOLD FLC TO DSND BACK TO FL200 'DUE TO TFC,' THEN THEY RECEIVED A CLB RA AS INTRUDER ACFT SHOWED 400 FT BELOW THEM.
Narrative: WE WERE IN THE CLR, CLBING TO FL210. PASSING THROUGH FL201 WE RECEIVED A TFC ALERT ON THE TCASII AND IT POPPED UP ON THE MULTI-FUNCTION DISPLAY. THE TARGET WAS SHOWING 1400 FT ABOVE US AND WAS ALMOST OVERLAID ON TOP OF OUR POS. AT FL205 WE WERE TOLD BY THE CTLR TO DSND BACK DOWN TO FL200. NO URGENCY WAS STRESSED, JUST 'DUE TO TFC.' PASSING THROUGH FL206 AND WHILE INITIATING A DSCNT BACK DOWN TO FL200, WE RECEIVED AN RA OF 'CLB, CLB.' THE TFC WAS NOW OVERLAID ON TOP OF US AND NOW SHOWED 400 FT BELOW US. WE NEVER SAW THE OTHER ACFT OR HEARD CTR ISSUE ANY TYPE OF CLRNC TO THEM. OBVIOUSLY, IT WAS A VERY CONFUSING 15 SECONDS GOING FROM CLB TO DSND TO CLB! THE CTLR WAS DEALING WITH DATA THAT WAS BEING UPDATED VERY SLOWLY WHILE OUR TCASII SHOWED A MORE REALISTIC PICTURE. OUR FIRST REACTION ON THE TA WAS 'WHERE IS HE?' WITH THE TFC ALMOST ON TOP OF US ON THE MULTI-FUNCTION DISPLAY, AND WITH THE OVERLAYING OF GRAPHICAL DATA, IT MADE IT HARD TO INTERPRET THE DATA RAPIDLY. WITH THE RA WE KNEW WHERE WE STOOD. I JUST WISH IT WOULD HAVE COME QUICKER. OBVIOUSLY, HUMAN ERROR SOMEWHERE IN THE ATC SYS OR THE OTHER ACFT CONTRIBUTED TO THIS SIT. I WAS ALSO UNDER THE MISTAKEN IMPRESSION THAT AN ALARM IN THE ATC COMPUTER WOULD ALERT THE CTLR WHEN 2 JETS WERE GOING TO OCCUPY THE SAME AIRSPACE AND IN THE PAST OUR TCASII HAD GIVEN US CONSIDERABLY MORE WARNING THAN IT DID ON THIS OCCASION. EVIDENTLY, THE VERT CLOSURE RATES WERE TOO HIGH FOR EITHER SYS TO HANDLE AFTER THE HUMAN ERROR HAD BEEN MADE. I WOULD LIKE TO SEE BOTH THE ARTCC AND TCASII SYS UPDATED FURTHER. IN THE MEANTIME, WEAR A RABBIT'S FOOT!
Data retrieved from NASA's ASRS site as of July 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.