DRYDEN, NY, USA
N6886D
CESSNA 425
THE PLT STATED THAT HE WAS UTILIZING THE AUTOPILOT AND FLT DIRECTOR TO EXECUTE THE ILS APPCH TO RWY 32. THE AUTOPILOT WAS TRACKING THE LOCALIZER WHILE THE PILOT CONTROLLED THE RATE OF DESCENT ALONG THE GLIDESLOPE WITH PITCH COMMAND WHEEL ON THE AUTOPILOT, USING THE COMMAND BARS AS A STEERING REFERENCE IN ADDITION TO THE RAW DATA GLIDESLOPE NEEDLE ON THE HSI. ALL SEEMED NORMAL, ACCORDING TO THE PILOT, UNTIL THE ACFT STRUCK TREES ABOUT 450 FEET ABOVE ARPT ELEVATION TWO MILES SHORT OF THE RWY AND CAME TO REST ON THE LOCALIZER CENTERLINE. A ZERO FT CEILING WITH AN EIGHTH MILE VSBY EXISTED AT THE ARPT. DURING THE INVSTGTN, IT WAS DETERMINED THAT THE 1000A IFCS WILL NOT PROVIDE VERTICAL STEERING COMMANDS AS OPERATED BY THE PLT, BUT IS DRIVEN BY THE PITCH WHEEL. THIS IS NOT SPECIFICALLY STATED IN THE POH. THE PLT HAD FLOWN EXTENSIVELY WITH THE 800 SERIES IFCS WHICH WILL PROVIDE THE EXPECTED STEERING COMMANDS. EXTENSIVE DAMAGE PRECLUDED A FUNCTIONAL TEST OF THE RAW DATA GLIDESLOPE NEEDLE.
Source: NTSB Aviation Accident Database
Aviation Accidents App
In-Depth Access to Aviation Accident Reports
