Date & Time: Mar 2, 1997 at 1913 LT
Registration:
N117WM
Survivors:
Yes
Schedule:
Las Vegas - Salt Lake City
MSN:
BB-662
YOM:
1980
Crew on board:
1
Crew fatalities:
0
Pax on board:
3
Pax fatalities:
1
Other fatalities:
0
Total fatalities:
1
Captain / Total flying hours:
8172
Captain / Total hours on type:
1841
Aircraft flight hours:
4692
Circumstances:
The flight was on a coupled instrument landing system (ILS) approach with 1/2 mile visibility in snow showers. Three successive fixes on the localizer are defined by distance measuring equipment (DME) paired with the ILS; prior to the ILS DME commissioning 6 months before the accident, the DME fixes were defined by a VORTAC 4.7 nautical miles past the ILS DME. The aircraft was 800 feet high at the first fix and 1,500 feet high at the second, but approximately on altitude 4.7 nautical miles past the first and second fixes, respectively. It passed the outer marker 900 feet high and captured the glide slope from above about 1.8 nautical miles from the threshold, 500 feet above decision height (DH) and 700 feet above touchdown. The aircraft was on glide slope for 28 seconds, during which time its speed decayed to stall speed; it then dropped below glide slope and crashed 1.3 nautical miles short of the threshold. The pilot's FLT DIR DME-1/ DME-2 switch, which control the DME display on the pilot's horizontal situation indicator (HSI), was found set to DME-2; the NAV-2 radio was set to the VORTAC frequency. Up to 800 feet may be required for stall recovery.
Probable cause:
The pilot's failure to maintain adequate airspeed on the ILS approach, resulting in a stall. Factors included: low visibility; the pilot's selection of the improper DME for the approach; his resulting failure to attain the proper descent profile for the approach; and insufficient altitude available for stall recovery.
Final Report:
N117WM.pdf127.27 KB