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Medium large transport encounters wake turbulence following widebody transport. Has TCASII RA, responds.
| Attributes | |
| ACN | 191689 |
| Time | |
| Date | 199110 |
| Day | Mon |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| Locale Reference | atc facility : buj airport : dfw |
| State Reference | TX |
| Altitude | msl bound lower : 10600 msl bound upper : 11300 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Route In Use | arrival star : star enroute airway : dfw |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Widebody, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other Other |
| Flight Phase | cruise other |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : cfi pilot : atp pilot : flight engineer |
| Experience | flight time last 90 days : 100 flight time total : 15000 flight time type : 2500 |
| ASRS Report | 191689 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : atp |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa |
| Resolutory Action | flight crew : took evasive action |
| Consequence | Other |
| Miss Distance | vertical : 600 |
| Supplementary | |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | other |
Narrative:
Flight on STAR to dfw at 11000 ft assigned in trail with widebody transport at 5 mi. Aircraft entered moderate turbulence and began roll to right and lost approximately 400 ft altitude. (Flight was on autoplt). TCASII issued TA followed by immediate RA with climb command issued. Flight crew took evasive action by following TA. Aircraft continued climb to 11300 ft before TCASII issued clear of conflict. Suspect that wing tip vortices from preceeding widebody transport caused initial altitude loss. Although widebody transport not defined as 'heavy', more separation is probably in order. Flight crew did not see intruder aircraft by visual sighting but it was displayed on the TCASII screen at 12 O'clock approximately 600 below and level. Range 5-10 mi.
Original NASA ASRS Text
Title: MLG ENCOUNTERS WAKE TURB FOLLOWING WDB. HAS TCASII RA, RESPONDS.
Narrative: FLT ON STAR TO DFW AT 11000 FT ASSIGNED IN TRAIL WITH WDB AT 5 MI. ACFT ENTERED MODERATE TURB AND BEGAN ROLL TO R AND LOST APPROX 400 FT ALT. (FLT WAS ON AUTOPLT). TCASII ISSUED TA FOLLOWED BY IMMEDIATE RA WITH CLB COMMAND ISSUED. FLC TOOK EVASIVE ACTION BY FOLLOWING TA. ACFT CONTINUED CLB TO 11300 FT BEFORE TCASII ISSUED CLR OF CONFLICT. SUSPECT THAT WING TIP VORTICES FROM PRECEEDING WDB CAUSED INITIAL ALT LOSS. ALTHOUGH WDB NOT DEFINED AS 'HVY', MORE SEPARATION IS PROBABLY IN ORDER. FLC DID NOT SEE INTRUDER ACFT BY VISUAL SIGHTING BUT IT WAS DISPLAYED ON THE TCASII SCREEN AT 12 O'CLOCK APPROX 600 BELOW AND LEVEL. RANGE 5-10 MI.
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.