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B737-700 captain reported a wake vortex encounter on descent into bna that provided enough distraction they missed a crossing restriction.
| Attributes | |
| ACN | 1091692 |
| Time | |
| Date | 201305 |
| Local Time Of Day | 0601-1200 |
| Place | |
| Locale Reference | ZME.ARTCC |
| State Reference | TN |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Make Model Name | B737-700 |
| Operating Under FAR Part | Part 121 |
| Flight Phase | Descent |
| Route In Use | STAR SWFFT 1 |
| Flight Plan | IFR |
| Aircraft 2 | |
| Make Model Name | Commercial Fixed Wing |
| Operating Under FAR Part | Part 121 |
| Route In Use | STAR SWFFT ONE |
| Flight Plan | IFR |
| Person 1 | |
| Function | Captain Pilot Not Flying |
| Qualification | Flight Crew Air Transport Pilot (ATP) |
| Experience | Flight Crew Last 90 Days 169 |
| Events | |
| Anomaly | Deviation - Altitude Crossing Restriction Not Met Deviation - Procedural Clearance Inflight Event / Encounter Wake Vortex Encounter |
Narrative:
We were on the swfft 1 arrival into bna and had finished briefing the intersections and altitudes. The restriction at lense intersection is to cross at or above FL240. ATC gave us a clearance to descend now to FL300 and then cross lense at FL240. The first officer set 240 in the MCP and started our descent to FL300. At that time; we encountered some wake turbulence; which rolled the aircraft into a 20 to 25 degree right bank and the autopilot disengaged. The first officer quickly resumed control and had to apply almost full left aileron to stop the roll; yet the aircraft remained in the bank for two to three seconds before the wings rolled level. He returned the aircraft to a stabilized profile and then re-engaged the autopilot with the aircraft back LNAV and VNAV path.I did not notice that we had forgotten to change the 'at or above altitude' at lense to a hard altitude of 240. It was in our descent through FL290 and about eight miles from lense intersection that I noticed we were not going to make our altitude and reported it to ATC as we crossed the intersection at approximately FL260. They then gave us a clearance to descend to FL240. The flight continued to bna without any further problems.
Original NASA ASRS Text
Title: B737-700 Captain reported a wake vortex encounter on descent into BNA that provided enough distraction they missed a crossing restriction.
Narrative: We were on the SWFFT 1 arrival into BNA and had finished briefing the intersections and altitudes. The restriction at LENSE Intersection is to cross at or above FL240. ATC gave us a clearance to descend now to FL300 and then cross LENSE at FL240. The First Officer set 240 in the MCP and started our descent to FL300. At that time; we encountered some wake turbulence; which rolled the aircraft into a 20 to 25 degree right bank and the autopilot disengaged. The First Officer quickly resumed control and had to apply almost full left aileron to stop the roll; yet the aircraft remained in the bank for two to three seconds before the wings rolled level. He returned the aircraft to a stabilized profile and then re-engaged the autopilot with the aircraft back LNAV and VNAV PATH.I did not notice that we had forgotten to change the 'at or above altitude' at LENSE to a hard altitude of 240. It was in our descent through FL290 and about eight miles from LENSE Intersection that I noticed we were not going to make our altitude and reported it to ATC as we crossed the intersection at approximately FL260. They then gave us a clearance to descend to FL240. The flight continued to BNA without any further problems.
Data retrieved from NASA's ASRS site as of July 2013 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.