 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
A B757-200 crew, on final to sfo, encountered an autoplt uncommanded roll input requiring autoplt disconnect.
| Attributes | |
| ACN | 558357 |
| Time | |
| Date | 200208 |
| Day | Thu |
| Place | |
| Locale Reference | airport : sfo.airport |
| State Reference | CA |
| Altitude | msl single value : 3700 |
| Environment | |
| Flight Conditions | VMC |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | tracon : o90.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B757-200 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | descent : approach |
| Flight Plan | IFR |
| Aircraft 2 | |
| Controlling Facilities | tracon : o90.tracon |
| Operator | common carrier : air carrier |
| Make Model Name | B747 Undifferentiated or Other Model |
| Flight Phase | descent : approach |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : flight engineer pilot : commercial pilot : atp pilot : multi engine |
| Experience | flight time last 90 days : 180 flight time total : 13000 flight time type : 5700 |
| ASRS Report | 558357 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | aircraft equipment problem : less severe other anomaly other other spatial deviation |
| Independent Detector | other flight crewa other flight crewb |
| Resolutory Action | flight crew : overrode automation flight crew : regained aircraft control flight crew : overcame equipment problem |
| Consequence | other |
| Supplementary | |
| Problem Areas | Aircraft |
| Primary Problem | Aircraft |
Narrative:
On FMS bridge visual runway 28R into sfo international at 3700 ft MSL, descending -900 FPM, speed 180 KTS, flaps set at 15 degrees, right autoplt command, VNAV, LNAV, on left navigation track, above VNAV path, gear down, smooth air, above heavy traffic (B747) ahead flight path and at least 5 mi behind this B747. Autoplt seemed to malfunction because airplane did a rapid smooth roll to right to 30-40 degree angle of bank. First officer disconnected autoplt (he was PF) and manually leveled plane. I, the captain, immediately took control of plane, became PF, and landed manually with flaps 30 degrees. After autoplt disconnected, plane flew normally. We had no EICAS messages, advisories, cautions, or warnings. No autoplt warnings -- probably an autoplt malfunction with uncommanded roll. If we had not acted promptly, plane would have rolled right on over.
Original NASA ASRS Text
Title: A B757-200 CREW, ON FINAL TO SFO, ENCOUNTERED AN AUTOPLT UNCOMMANDED ROLL INPUT REQUIRING AUTOPLT DISCONNECT.
Narrative: ON FMS BRIDGE VISUAL RWY 28R INTO SFO INTL AT 3700 FT MSL, DSNDING -900 FPM, SPD 180 KTS, FLAPS SET AT 15 DEGS, R AUTOPLT COMMAND, VNAV, LNAV, ON L NAV TRACK, ABOVE VNAV PATH, GEAR DOWN, SMOOTH AIR, ABOVE HVY TFC (B747) AHEAD FLT PATH AND AT LEAST 5 MI BEHIND THIS B747. AUTOPLT SEEMED TO MALFUNCTION BECAUSE AIRPLANE DID A RAPID SMOOTH ROLL TO R TO 30-40 DEG ANGLE OF BANK. FO DISCONNECTED AUTOPLT (HE WAS PF) AND MANUALLY LEVELED PLANE. I, THE CAPT, IMMEDIATELY TOOK CTL OF PLANE, BECAME PF, AND LANDED MANUALLY WITH FLAPS 30 DEGS. AFTER AUTOPLT DISCONNECTED, PLANE FLEW NORMALLY. WE HAD NO EICAS MESSAGES, ADVISORIES, CAUTIONS, OR WARNINGS. NO AUTOPLT WARNINGS -- PROBABLY AN AUTOPLT MALFUNCTION WITH UNCOMMANDED ROLL. IF WE HAD NOT ACTED PROMPTLY, PLANE WOULD HAVE ROLLED RIGHT ON OVER.
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.