Boise Air Terminal-Gowen Airport
Aircraft Accident/Incident Report

Boise, Idaho 83715
Thursday, December 7, 1995 21:24 MST

The flight was on a coupled Category I ILS approach in fog and dark night conditions. After passing the final approach fix, the crew was notified that the runway visibility range (RVR) was below minimums. The captain continued the approach to decision height (DH) in accordance with company operations specifications. He visually acquired the runway prior to DH and continued toward landing, disengaging the autopilot about 60 feet above the runway. The flight data recorder (FDR) indicated that the aircraft heading then began to drift right. The cockpit crewmembers stated that upon noticing the drift, the captain countered it with aileron and rudder inputs. The FDR indicated a roll angle of -7.50 degrees at the instant maximum vertical G and minimum altitude readings were recorded, increasing to -14.90 degrees one second later. Damage was observed to the left outboard slats and flap after the flight. A Boeing chart indicated that at a pitch angle of 3.9 degrees and landing sink rate of 10 feet per second, the outboard slat and flap will contact the ground at a roll angle between 7.45 and 8.7 degrees.

the pilot-in-command's misjudgment of the remedial action necessary to correct the aircraft's misalignment with the runway. The dark night conditions, fog, and the pilot-in-command's failure to maintain proper alignment with the runway were factors.