Aviation Accident Summaries

Aviation Accident Summary CHI96LA039

STEVENS POINT, WI, USA

Aircraft #1

N6293F

CESSNA 172

Analysis

The pilot was advised that icing conditions existed and were forecast along his route of flight. The pilot reported that ten minutes from Stevens Point, Wisconsin, he began picking up ice on his windscreen. He requested a full VOR approach. The pilot reported picking up 3/4 inch of ice during the approach. The pilot descended to the minimum descent altitude (MDA) and did not have the airport in sight. He saw a road and descended below the MDA and continued toward the airport. He saw the airport when he was over the top of it, and he tried a circling approach to runway 12. The pilot reported that the engine failed and the airplane hit trees and nosed into the ground. A witness at the airport reported that the airplane flew over the airport at 50 to 75 feet and that the engine sounded fine. He reported that the airplane disappeared into the haze and impacted the ground a short time later. An inspection of the engine indicated that the engine had continuity and there were no indications of mechanical problems.

Factual Information

On November 26, 1995, at 1258 central standard time (CST), a Cessna 172, N6293F, was substantially damaged when it impacted trees and the ground one quarter mile north of Stevens Point Municipal Airport, Stevens Point, Wisconsin. The pilot had requested the VOR Runway 30 approach to Stevens Point, Wisconsin, due to ice accumulation. The commercial pilot and passenger received serious injuries. The 14 CFR Part 91 flight departed Ionia, Michigan, en route to Duluth International Airport, Duluth, Minnesota. Instrument meteorological conditions prevailed. An instrument flight plan had been filed. The Federal Aviation Administration (FAA) reported that the pilot telephoned the Lansing Automated Flight Service Station (AFSS) at 1114 CDT to obtain a weather briefing and file a flight plan. The Lansing AFSS advised the pilot that there were advisories for icing along his intended route of flight. The briefer stated, "...once you move north basically of Green Bay, they look for occasional rime mixed icing in clouds and in precip below 10,000 feet. Additional advisories in effect for IFR conditions. It does cover your entire route of flight... ." The briefer also advised the pilot that occasional light freezing drizzle was being reported in the central portions of Wisconsin. The AFSS weather adviser told the pilot there were reports of light freezing drizzle and fog west from central Wisconsin to Duluth, Minnesota. The weather at Duluth was reporting a measured 1800 foot overcast with ten miles visbility. The temperature and dew point were both 23 degrees. The briefer also advised that there were two pilot reports of icing in the Duluth area. A DC-9 had reported moderate mixed icing ten miles south of Duluth during climbout. A Citation had reported a trace of rime icing during climb. The Lansing AFSS briefer told the pilot that the forecast temperatures aloft were between plus two degrees to minus five degrees at six thousand feet along his intended flight path. The pilot filed an instrument flight plan at 1125 CST. His destination airport was Duluth International Airport, Duluth, Minnesota, and his alternate was Sky Harbor Airport, Duluth, Minnesota, which was 10 nautical miles from his destination airport. The pilot reported that he departed Ionia, Michigan, about 1130 CST and crossed Lake Michigan at 4,000 feet. He reported that he had ground contact until about ten minutes out from Stevens Point, Wisconsin. He reported that the outside air temperature was 4 degrees at 4,000 feet. He reported that he started picking up ice on his windscreen. At 1238 CST he requested a VOR Runway 30 approach into Stevens Point, Wisconsin, due to icing. The controller asked the pilot if he expected the full procedure turn and the pilot advised him he did. The pilot reported that he was cleared to 3,000 feet and he flew the full approach at that altitude. He reported that he was getting ice on the windscreen, tires, struts, and wings. He reported that during the approach, he picked up about 3/4 inch of ice. At 1247 CST the controller read the pilot the weather reported at Wausau, Wisconsin, 24 nautical miles to the north. The Wausau weather was, "...estimated ceiling three hundred overcast, visibility two and three quarters, fog, temperature two seven, dew point two four, wind zero eight zero at six, altimeter two nine seven nine." The weather at Central Wisconsin Airport, Mosinee, Wisconsin, 15 nautical miles to the north, at 1245 CST was: "...partially obscurred, measured two hundred overcast, 1/2 mile fog, temperature 25 degrees, dew point 23 degrees, winds 080 at 7 knots, altimeter 29.77, fog 8." The pilot, however, was not aware of the weather in Mosinee, Wisconsin. The pilot continued with the approach and reported that he saw the ground when the airplane was about .7 miles from the airport at 1740 feet. He reported that he saw a road below him so he descended below the Minimum Descent Altitude (MDA) and continued toward the airport. He reported that he finally saw the airport when he was over the top of it. He attempted to make a left circling approach to runway 12. He reported that while entering the left traffic pattern, the engine failed. He reported that he was not sure if it was a full or partial power failure. He reported that he had tried applying full power. He reported that he had the carburetor heat on during the entire approach. The airplane impacted trees and nosed down hitting the ground. The pilot does not remember anything else about the accident. The passenger's statements concerning the accident, taken shortly after the accident and during subsequent telephone conversations, coincide with the pilot's account. A witness at the airport reported observing the airplane as it flew over the airport. He reported that the airplane was at about 50 to 75 feet in altitude. He reported that the engine sounded like it was running fine with no sputtering. He reported that the airplane was in a left turn and going in a direction that was right in line with the crash site. He reported that the airplane disappeared in the fog and haze. The witness reported that he examined the airplane shortly after the accident and reported that the leading edge of the wing had 1/4 inch of slushy ice on it. The witness also reported that the weather at the time of the accident was foggy and hazy with freezing rain. An Airworthiness Inspector from the Federal Aviation Administration examined the aircraft. He reported that the engine had nearly separated from the firewall and that the carburetor had separated from the engine. He inspected the engine and reported that it had continuity, and that there were no indications of a mechanical problem. An examination of the VOR 30 approach plate for Stevens Point Municipal Airport, Stevens Point, Wisconsin, indicated that when the Wausau altimeter was used for the approach, the MDA increased by 80 feet from 1,740 feet to 1,820 feet.

Probable Cause and Findings

flying into known icing conditions and descending below the minimum descent altitude.

 

Source: NTSB Aviation Accident Database

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