|37000 Feet||Browse and search NASA's
Aviation Safety Reporting System
|Local Time Of Day||1201 To 1800|
|Locale Reference||airport : den|
|Altitude||msl bound lower : 14000|
msl bound upper : 14000
|Controlling Facilities||tracon : den|
tower : pit
|Operator||common carrier : air carrier|
|Make Model Name||B737-400|
|Operating Under FAR Part||Part 121|
|Navigation In Use||Other |
|Flight Phase||descent : approach|
|Affiliation||government : faa|
|Function||observation : observer|
|Qualification||controller : non radar|
|Affiliation||company : air carrier|
|Function||flight crew : captain|
oversight : pic
|Qualification||pilot : atp|
|Anomaly||other anomaly other|
other spatial deviation
|Independent Detector||aircraft equipment other aircraft equipment : unspecified|
other flight crewa
|Resolutory Action||flight crew : overcame equipment problem|
flight crew : returned to intended course or assigned course
|Primary Problem||Flight Crew Human Performance|
|Air Traffic Incident||other|
During approach to den, on a left downwind to runway 16, at 14000 ft, the B737-400 made an uncommanded roll to the right. Alarms sounded. I noticed on the copilot's monitor the letters cws roll. The pilot turned the yoke to the left and grabbed the throttle. There were no other aircraft flying above us or even close, according to the traffic on the TCASII. It was never explained what caused the 20-30 degree roll. It was my first unpleasurable flight. I could tell by the pilot's and first officer's reaction, that they were just as surprised and unhappy about what happened as I was.
Original NASA ASRS Text
Title: JUMPSEAT RIDER RPTED ACR B737-400 UNCOMMANDED ROLL TO THE R. RPTR SAW 'CWS ROLL' ILLUMINATED ON FO'S FLT MODE ANNUNCIATOR. CAPT OVERCAME EQUIP PROB BY MOVING YOKE BACK TO L.
Narrative: DURING APCH TO DEN, ON A L DOWNWIND TO RWY 16, AT 14000 FT, THE B737-400 MADE AN UNCOMMANDED ROLL TO THE R. ALARMS SOUNDED. I NOTICED ON THE COPLT'S MONITOR THE LETTERS CWS ROLL. THE PLT TURNED THE YOKE TO THE L AND GRABBED THE THROTTLE. THERE WERE NO OTHER ACFT FLYING ABOVE US OR EVEN CLOSE, ACCORDING TO THE TFC ON THE TCASII. IT WAS NEVER EXPLAINED WHAT CAUSED THE 20-30 DEG ROLL. IT WAS MY FIRST UNPLEASURABLE FLT. I COULD TELL BY THE PLT'S AND FO'S REACTION, THAT THEY WERE JUST AS SURPRISED AND UNHAPPY ABOUT WHAT HAPPENED AS I WAS.
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.