 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
An light transport was nearly upset by the wake turbulence of an large transport in the night traffic pattern.
| Attributes | |
| ACN | 238067 |
| Time | |
| Date | 199304 |
| Day | Thu |
| Local Time Of Day | 1801 To 2400 |
| Place | |
| Locale Reference | airport : dfw |
| State Reference | TX |
| Altitude | msl bound lower : 3000 msl bound upper : 3000 |
| Environment | |
| Flight Conditions | VMC |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tower : dfw |
| Operator | common carrier : air carrier |
| Make Model Name | Light Transport, Low Wing, 2 Turbojet Eng |
| Flight Phase | descent : approach |
| Route In Use | approach : straight in |
| Flight Plan | IFR |
| Aircraft 2 | |
| Operator | common carrier : air carrier |
| Make Model Name | Medium Large Transport, Low Wing, 2 Turbojet Eng |
| Navigation In Use | Other |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 170 flight time total : 8100 flight time type : 400 |
| ASRS Report | 238067 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : commercial pilot : instrument |
| Events | |
| Anomaly | inflight encounter other other anomaly other anomaly other |
| Independent Detector | other flight crewa |
| Resolutory Action | controller : issued new clearance flight crew : became reoriented other |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
Approaching dfw from the northwest following medium large transport traffic when controller saw an opportunity to allow us to land runway 35R. We were 3000 ft MSL at 210 KIAS assigned airspeed when told to follow large transport over LOM for runway 35R. Crossed behind medium large transport on final for runway 36L still at 3000 ft and intercepted localizer for runway 35R. Switched to tower frequency and were told we had a 70 KT overtake on large transport and began slowing. Began descent from 3000 ft noting we were full deflection above GS. I judged this to be perfectly acceptable knowing the nasty reputation the large transport has for generating wake turbulence and, in fact, fully intended to remain high on final. Tower advised 'cleared to land following traffic 2 1/2 ahead, caution wake turbulence.' I thought we would be safely above his wake. Shortly after, my aircraft (light transport) rolled to the right to an angle of approximately 100 degrees (more than 90 degrees). Full opposite control input did not have any affect in stopping this roll. IAS began dropping and throttles were then firewalled. As we rolled right, we had also turned slightly in that direction and I assume we flew out of that vortex and were able to right the aircraft. Then we hit what I assume was his right wing vortex and the aircraft (mine) began to roll left. We flew through this vortex fairly quickly, probably due to our new (uncommanded) heading, and our bank did not exceed 60 degrees. We recovered from this roll on a heading of about 080 degrees and declared a missed approach. Tower asked if we could enter a base for runway 31R and land. We did, and landed without further incident. The large transport had obviously been very high on his approach for some reason, possibly an earlier TCASII resolution. Our attention had been focused on the medium large transport we were originally following, thus I was unaware of the large transport's glide path. I feel someone (controllers) should have noticed this and realized a wake encounter was inevitable. Secondly, I feel the large transport should be classified as a 'heavy' jet and increased spacing should be used.
Original NASA ASRS Text
Title: AN LTT WAS NEARLY UPSET BY THE WAKE TURB OF AN LGT IN THE NIGHT TFC PATTERN.
Narrative: APCHING DFW FROM THE NW FOLLOWING MLG TFC WHEN CTLR SAW AN OPPORTUNITY TO ALLOW US TO LAND RWY 35R. WE WERE 3000 FT MSL AT 210 KIAS ASSIGNED AIRSPD WHEN TOLD TO FOLLOW LGT OVER LOM FOR RWY 35R. CROSSED BEHIND MLG ON FINAL FOR RWY 36L STILL AT 3000 FT AND INTERCEPTED LOC FOR RWY 35R. SWITCHED TO TWR FREQ AND WERE TOLD WE HAD A 70 KT OVERTAKE ON LGT AND BEGAN SLOWING. BEGAN DSCNT FROM 3000 FT NOTING WE WERE FULL DEFLECTION ABOVE GS. I JUDGED THIS TO BE PERFECTLY ACCEPTABLE KNOWING THE NASTY REPUTATION THE LGT HAS FOR GENERATING WAKE TURB AND, IN FACT, FULLY INTENDED TO REMAIN HIGH ON FINAL. TWR ADVISED 'CLRED TO LAND FOLLOWING TFC 2 1/2 AHEAD, CAUTION WAKE TURB.' I THOUGHT WE WOULD BE SAFELY ABOVE HIS WAKE. SHORTLY AFTER, MY ACFT (LTT) ROLLED TO THE R TO AN ANGLE OF APPROX 100 DEGS (MORE THAN 90 DEGS). FULL OPPOSITE CTL INPUT DID NOT HAVE ANY AFFECT IN STOPPING THIS ROLL. IAS BEGAN DROPPING AND THROTTLES WERE THEN FIREWALLED. AS WE ROLLED R, WE HAD ALSO TURNED SLIGHTLY IN THAT DIRECTION AND I ASSUME WE FLEW OUT OF THAT VORTEX AND WERE ABLE TO RIGHT THE ACFT. THEN WE HIT WHAT I ASSUME WAS HIS R WING VORTEX AND THE ACFT (MINE) BEGAN TO ROLL L. WE FLEW THROUGH THIS VORTEX FAIRLY QUICKLY, PROBABLY DUE TO OUR NEW (UNCOMMANDED) HDG, AND OUR BANK DID NOT EXCEED 60 DEGS. WE RECOVERED FROM THIS ROLL ON A HDG OF ABOUT 080 DEGS AND DECLARED A MISSED APCH. TWR ASKED IF WE COULD ENTER A BASE FOR RWY 31R AND LAND. WE DID, AND LANDED WITHOUT FURTHER INCIDENT. THE LGT HAD OBVIOUSLY BEEN VERY HIGH ON HIS APCH FOR SOME REASON, POSSIBLY AN EARLIER TCASII RESOLUTION. OUR ATTN HAD BEEN FOCUSED ON THE MLG WE WERE ORIGINALLY FOLLOWING, THUS I WAS UNAWARE OF THE LGT'S GLIDE PATH. I FEEL SOMEONE (CTLRS) SHOULD HAVE NOTICED THIS AND REALIZED A WAKE ENCOUNTER WAS INEVITABLE. SECONDLY, I FEEL THE LGT SHOULD BE CLASSIFIED AS A 'HVY' JET AND INCREASED SPACING SHOULD BE USED.
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.