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37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
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Air carrier receives rapid TA, RA TCASII alerts. Starts to respond, then sights traffic. Not a factor. Returns to assigned altitude.
| Attributes | |
| ACN | 218264 |
| Time | |
| Date | 199208 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : tla |
| State Reference | FO |
| Altitude | msl bound lower : 31000 msl bound upper : 31000 |
| Environment | |
| Flight Conditions | Mixed |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | Widebody, Low Wing, 4 Turbojet Eng |
| Flight Phase | cruise other |
| Route In Use | enroute airway : ub4 |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Military Transport |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : flight engineer pilot : cfi pilot : atp |
| Experience | flight time last 90 days : 180 flight time total : 10000 flight time type : 2500 |
| ASRS Report | 218264 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified |
| Resolutory Action | flight crew : returned to intended course or assigned course flight crew : took evasive action |
| Consequence | Other |
| Miss Distance | horizontal : 3 vertical : 1800 |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Cruising at 31000 on UB4 30 mi to go to tla, scotland. Received proximate TA on TCASII, the TA, then RA to descend, descend now all within 10 seconds maximum total between proximate to RA. Autothrottles autoplt was disconnected by me, the PF, and pushover just began as we got a visual on the military target and it was immediately determined not a factor (high closure rate) altitude varied plus/minus 200 until autoplt was reconnected. Scottish control was queried and they could not believe we received a RA. Initial approximately altitude was plus 1800 ft and we believe remained plus 1800 ft. Our only clue might have been high rate of descent to 33000? And high speed (closure) to give such a quick RA and quick clear of conflict. TCASII must be further tested before a case happens where 1 deviation to a RA leads to another/another RA everyone doing their own thing. Line flying is not a good test bed for experiments.
Original NASA ASRS Text
Title: ACR RECEIVES RAPID TA, RA TCASII ALERTS. STARTS TO RESPOND, THEN SIGHTS TFC. NOT A FACTOR. RETURNS TO ASSIGNED ALT.
Narrative: CRUISING AT 31000 ON UB4 30 MI TO GO TO TLA, SCOTLAND. RECEIVED PROXIMATE TA ON TCASII, THE TA, THEN RA TO DSND, DSND NOW ALL WITHIN 10 SECONDS MAX TOTAL BTWN PROXIMATE TO RA. AUTOTHROTTLES AUTOPLT WAS DISCONNECTED BY ME, THE PF, AND PUSHOVER JUST BEGAN AS WE GOT A VISUAL ON THE MIL TARGET AND IT WAS IMMEDIATELY DETERMINED NOT A FACTOR (HIGH CLOSURE RATE) ALT VARIED PLUS/MINUS 200 UNTIL AUTOPLT WAS RECONNECTED. SCOTTISH CTL WAS QUERIED AND THEY COULD NOT BELIEVE WE RECEIVED A RA. INITIAL APPROX ALT WAS PLUS 1800 FT AND WE BELIEVE REMAINED PLUS 1800 FT. OUR ONLY CLUE MIGHT HAVE BEEN HIGH RATE OF DSCNT TO 33000? AND HIGH SPD (CLOSURE) TO GIVE SUCH A QUICK RA AND QUICK CLR OF CONFLICT. TCASII MUST BE FURTHER TESTED BEFORE A CASE HAPPENS WHERE 1 DEV TO A RA LEADS TO ANOTHER/ANOTHER RA EVERYONE DOING THEIR OWN THING. LINE FLYING IS NOT A GOOD TEST BED FOR EXPERIMENTS.
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.