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An air carrier flight leaves its assigned altitude of FL350 when receiving a TCASII RA for traffic. Later to be determined as a false warning by ATC and crew. Buf, ny.
| Attributes | |
| ACN | 460388 |
| Time | |
| Date | 200001 |
| Day | Tue |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : buf.airport |
| State Reference | NY |
| Altitude | msl bound lower : 34500 msl bound upper : 35000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | Large Transport, Low Wing, 2 Turbojet Eng |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 160 flight time total : 17000 flight time type : 2000 |
| ASRS Report | 460388 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : multi engine pilot : commercial |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment : tcas |
| Resolutory Action | controller : issued advisory flight crew : returned to assigned altitude |
| Consequence | faa : reviewed incident with flight crew other |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Aircraft |
| Primary Problem | Aircraft |
Narrative:
We were on a vector for traffic and received a TA followed within 3 seconds by an RA commanding a descent of about 1000 FPM. Within 5 additional seconds, we received an 'increase descent' command of about 1800 FPM. The RA resolved a few seconds after that, but we never received a 'clear of conflict' message. We followed the RA as it occurred and advised ATC. The descent was stopped at FL345 and we promptly returned to FL350. During the event, we briefly saw a target on the navigation display at our 6 O'clock position, close in, same altitude. ATC advised that there was no traffic in our vicinity at the time of the event.
Original NASA ASRS Text
Title: AN ACR FLT LEAVES ITS ASSIGNED ALT OF FL350 WHEN RECEIVING A TCASII RA FOR TFC. LATER TO BE DETERMINED AS A FALSE WARNING BY ATC AND CREW. BUF, NY.
Narrative: WE WERE ON A VECTOR FOR TFC AND RECEIVED A TA FOLLOWED WITHIN 3 SECONDS BY AN RA COMMANDING A DSCNT OF ABOUT 1000 FPM. WITHIN 5 ADDITIONAL SECONDS, WE RECEIVED AN 'INCREASE DSCNT' COMMAND OF ABOUT 1800 FPM. THE RA RESOLVED A FEW SECONDS AFTER THAT, BUT WE NEVER RECEIVED A 'CLR OF CONFLICT' MESSAGE. WE FOLLOWED THE RA AS IT OCCURRED AND ADVISED ATC. THE DSCNT WAS STOPPED AT FL345 AND WE PROMPTLY RETURNED TO FL350. DURING THE EVENT, WE BRIEFLY SAW A TARGET ON THE NAV DISPLAY AT OUR 6 O'CLOCK POS, CLOSE IN, SAME ALT. ATC ADVISED THAT THERE WAS NO TFC IN OUR VICINITY AT THE TIME OF THE EVENT.
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.