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DO328 excursion from assigned altitude while in heavy turbulence, with up- and downdrafts, and precipitation causing inadvertent autoplt disconnect.
| Attributes | |
| ACN | 546928 |
| Time | |
| Date | 200205 |
| Day | Tue |
| Local Time Of Day | 0601 To 1200 |
| Place | |
| Locale Reference | airport : day.airport |
| State Reference | OH |
| Altitude | msl bound lower : 24000 msl bound upper : 24500 |
| Environment | |
| Flight Conditions | IMC |
| Weather Elements | Turbulence Rain |
| Light | Daylight |
| Aircraft 1 | |
| Controlling Facilities | artcc : zob.artcc tower : zzz.tower |
| Operator | common carrier : air carrier |
| Make Model Name | Do 328 TP (Turboprop) |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | other |
| Flight Phase | cruise : level |
| Route In Use | enroute airway : j149.airway |
| Flight Plan | IFR |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | flight crew : captain oversight : pic |
| Qualification | pilot : instrument pilot : multi engine pilot : atp |
| Experience | flight time last 90 days : 222 flight time total : 3512 flight time type : 1952 |
| ASRS Report | 546928 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | flight crew : first officer |
| Events | |
| Anomaly | altitude deviation : excursion from assigned altitude inflight encounter : weather inflight encounter : turbulence non adherence : clearance other anomaly |
| Independent Detector | aircraft equipment other aircraft equipment : altimeter/autoplt ind other flight crewa |
| Resolutory Action | flight crew : returned to assigned altitude flight crew : regained aircraft control |
| Supplementary | |
| Problem Areas | Aircraft Flight Crew Human Performance Weather |
| Primary Problem | Flight Crew Human Performance |
| Air Traffic Incident | Pilot Deviation |
Narrative:
The problem arose while the inexperienced first officer was PF in solid IMC with severe turbulence and updraft and heavy precipitation. Upon entering the localized conditions (the radar showed zero echoes along our entire route) the turbulence within the precipitation area knocked off the autoplt. When the autoplt is inadvertently disconnected, the flight director is lost simultaneously. The inexperienced first officer (2 months on line) was not quick enough to arrest the ascent to 500 ft above assigned altitude in the updraft. Both pilots manipulated the controls to level off the aircraft. The biggest factor affecting human performance is the sudden loss of flight director when it becomes necessary to hand fly the airplane (raw data) because of autoplt disconnect. It would be beneficial for experienced and inexperienced pilots for the flight director logic to not remove it from the primary flight display during uncommanded autoplt disconnect.
Original NASA ASRS Text
Title: DO328 EXCURSION FROM ASSIGNED ALT WHILE IN HVY TURB, WITH UP- AND DOWNDRAFTS, AND PRECIP CAUSING INADVERTENT AUTOPLT DISCONNECT.
Narrative: THE PROB AROSE WHILE THE INEXPERIENCED FO WAS PF IN SOLID IMC WITH SEVERE TURB AND UPDRAFT AND HVY PRECIP. UPON ENTERING THE LOCALIZED CONDITIONS (THE RADAR SHOWED ZERO ECHOES ALONG OUR ENTIRE RTE) THE TURB WITHIN THE PRECIP AREA KNOCKED OFF THE AUTOPLT. WHEN THE AUTOPLT IS INADVERTENTLY DISCONNECTED, THE FLT DIRECTOR IS LOST SIMULTANEOUSLY. THE INEXPERIENCED FO (2 MONTHS ON LINE) WAS NOT QUICK ENOUGH TO ARREST THE ASCENT TO 500 FT ABOVE ASSIGNED ALT IN THE UPDRAFT. BOTH PLTS MANIPULATED THE CTLS TO LEVEL OFF THE ACFT. THE BIGGEST FACTOR AFFECTING HUMAN PERFORMANCE IS THE SUDDEN LOSS OF FLT DIRECTOR WHEN IT BECOMES NECESSARY TO HAND FLY THE AIRPLANE (RAW DATA) BECAUSE OF AUTOPLT DISCONNECT. IT WOULD BE BENEFICIAL FOR EXPERIENCED AND INEXPERIENCED PLTS FOR THE FLT DIRECTOR LOGIC TO NOT REMOVE IT FROM THE PRIMARY FLT DISPLAY DURING UNCOMMANDED AUTOPLT DISCONNECT.
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.