 |
37000 Feet | Browse and search NASA's Aviation Safety Reporting System |
|
An FK28 flight crew experiences an autoplt altitude hold malfunction and a subsequent excursion from their assigned altitude of FL290 while detouring thunderstorm activity 30 mi south of reo VOR, or.
| Attributes | |
| ACN | 476650 |
| Time | |
| Date | 200006 |
| Day | Thu |
| Local Time Of Day | 1201 To 1800 |
| Place | |
| State Reference | OR |
| Altitude | msl bound lower : 28600 msl bound upper : 29000 |
| Environment | |
| Flight Conditions | Mixed |
| Weather Elements | Thunderstorm |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zlc.artcc |
| Operator | common carrier : air carrier |
| Make Model Name | F28 Undifferentiated or Other Model |
| Operating Under FAR Part | Part 121 |
| Flight Phase | cruise : level |
| Route In Use | enroute airway : ns.airway |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : atp |
| Experience | flight time last 90 days : 200 flight time total : 10530 flight time type : 500 |
| ASRS Report | 476650 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Qualification | pilot : instrument pilot : commercial pilot : multi engine |
| Events | |
| Anomaly | aircraft equipment problem : less severe altitude deviation : excursion from assigned altitude inflight encounter : weather non adherence : clearance other anomaly other |
| Independent Detector | aircraft equipment : altitude alert other controllera other flight crewa |
| Resolutory Action | controller : issued advisory flight crew : returned to assigned altitude |
| Consequence | faa : reviewed incident with flight crew |
| Supplementary | |
| Problem Areas | Flight Crew Human Performance Weather Aircraft |
| Primary Problem | Aircraft |
| Air Traffic Incident | Pilot Deviation |
Narrative:
While concentrating on keeping maximum bank (15 degrees, FK28, FL290) to avoid a thunderstorm build-up, with all modes of the autoplt engaged the altitude hold function disengaged. The green 'altitude' light on the glare shield remained illuminated, giving me an erroneous indication. After a loss of 300 ft, the altitude alerter gave me a warning. I disengaged the autoplt and recovered my altitude with a momentary maximum loss of 400 ft. ZLC controller asked my altitude, and I advised the autoplt failed and that we were back at FL290. I re-engaged the autoplt, and a few mins later got the same failure with the same indicator failure. I recorded the failure and indicator failure in the maintenance log. I have previously experienced the altitude hold function disengaging in the FK28, but never with the 'altitude' engage light staying illuminated.
Original NASA ASRS Text
Title: AN FK28 FLC EXPERIENCES AN AUTOPLT ALT HOLD MALFUNCTION AND A SUBSEQUENT EXCURSION FROM THEIR ASSIGNED ALT OF FL290 WHILE DETOURING TSTM ACTIVITY 30 MI S OF REO VOR, OR.
Narrative: WHILE CONCENTRATING ON KEEPING MAX BANK (15 DEGS, FK28, FL290) TO AVOID A TSTM BUILD-UP, WITH ALL MODES OF THE AUTOPLT ENGAGED THE ALT HOLD FUNCTION DISENGAGED. THE GREEN 'ALT' LIGHT ON THE GLARE SHIELD REMAINED ILLUMINATED, GIVING ME AN ERRONEOUS INDICATION. AFTER A LOSS OF 300 FT, THE ALT ALERTER GAVE ME A WARNING. I DISENGAGED THE AUTOPLT AND RECOVERED MY ALT WITH A MOMENTARY MAX LOSS OF 400 FT. ZLC CTLR ASKED MY ALT, AND I ADVISED THE AUTOPLT FAILED AND THAT WE WERE BACK AT FL290. I RE-ENGAGED THE AUTOPLT, AND A FEW MINS LATER GOT THE SAME FAILURE WITH THE SAME INDICATOR FAILURE. I RECORDED THE FAILURE AND INDICATOR FAILURE IN THE MAINT LOG. I HAVE PREVIOUSLY EXPERIENCED THE ALT HOLD FUNCTION DISENGAGING IN THE FK28, BUT NEVER WITH THE 'ALT' ENGAGE LIGHT STAYING ILLUMINATED.
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.