ANC00LA029

The airplane collided with frozen pack ice, three miles from the airport, during a GPS instrument approach. Instrument conditions of 3/4 mile visibility in snow and fog were reported at the time of the accident. The pilot stated that he began a steep descent with the autopilot engaged. He indicated that as the airplane crossed the final approach course, the autopilot turned the airplane inbound toward the airport. He continued the steep descent, noted the airplane had overshot the course, and the autopilot was not correcting very well. He disengaged the autopilot and manually increased the correction heading to intercept the final approach course. During the descent he completed the landing checklist, extended the landing gear and flaps, and was tuning both the communications and navigation radios. The pilot said he looked up from tuning the radios to see the sea ice coming up too quickly to react, and impacted terrain. The pilot relayed there were no preaccident anomalies with the airplane, and that he 'did not stay ahead of the airplane.'

On February 21, 2000, about 1123 Alaska standard time, a Piper PA-31-T3 airplane, N219CS, sustained substantial damage when it collided with frozen pack ice on the Chukchi Sea, three miles west of Kotzebue, Alaska, during an instrument approach to the Ralph Wein Memorial Airport, Kotzebue. The solo airline transport pilot received minor injuries. The flight was being conducted under 14 CFR Part 135 as scheduled commuter Flight 170, by Cape Smythe Air Service, Inc., of Barrow, Alaska. The flight originated in Barrow, with intermediate stops at Wainwright, and Point Lay, Alaska. Instrument meteorological conditions of 3/4 mile visibility in snow and fog were reported at Kotzebue at 1116. The pilot filed an IFR flight plan while airborne, and received an IFR clearance to Kotzebue, from a point 35 miles northwest of Kotzebue.

The flight was cleared for the GPS Runway 8 approach, and at 1117, the pilot reported to the Kotzebue FAA Flight Service Station that the airplane was on a 10 mile final. The airplane did not arrive at the airport, and an ELT signal was received about 1124. A ground search located the airplane at 1215. Postaccident inspection by the FAA revealed the airplane remained upright, all three landing gear assemblies separated from the airplane, and substantial damage had occurred to both wings and the tail assembly.

The pilot stated in his NTSB Pilot/Operator report that once he was cleared for the approach, he began a steep descent with the autopilot engaged. He indicated that as the airplane crossed the final approach course about 10 miles from the airport at 3,000 feet msl, the autopilot turned the airplane inbound toward the airport. He said he continued the steep descent attempting to cross the final approach fix at 1,600 feet. He noted the airplane had overshot the course to the south, and the autopilot was not correcting very well. He disengaged the autopilot and manually increased the correction heading to intercept the final approach course. He said that during the descent he completed the landing checklist, extended the landing gear and flaps, and tuned the communications radio to the Automated Weather Observation System (AWOS) frequency to update the weather, which reported 3/4 miles visibility in snow. He then tuned the second navigation radio to the ILS frequency, thinking he should fly the ILS. The pilot said he looked up from tuning the radios to see the sea ice coming up too quickly to react, and the airplane impacted terrain.

A review of the Air Traffic Control radar plot of the airplane's ground track depicted the airplane overshooting the final approach course from north to south, and then overshooting to the north prior to impacting the sea ice.

During a telephone interview with the NTSB investigator-in-charge on March 2, the pilot stated the last altitude he remembered seeing was 800 feet msl. He related there were no preaccident anomalies with the airplane, and that this airplane's radar altimeter was not configured to generate an aural warning when the airplane descended below the selected minimum descent altitude, which he had set to 300 feet agl. The pilot commented that he "did not stay ahead of the airplane."