Aviation Accident Summaries

Aviation Accident Summary ANC17TA015

Pilot Point, AK, USA

Aircraft #1

N4261T

PIPER PA-32

Analysis

The airline transport pilot reported that, at 800 ft during a visual flight rules cross-country flight, the windscreen began accumulating trace ice, so he landed the airplane at an airport that he was flying over on the route. An agent at the destination airport reported to the pilot by telephone that the visibility at the destination was 10 miles, that the clouds were at 3,000 ft, and that no ice was reported. Subsequently, the pilot decided to continue the flight toward the destination to "take a look" at the weather conditions. He stated to the passenger that he would return to the departure airport if the weather was poor. After departing and within 8 miles of the airport, the windscreen began to accumulate ice again, and the pilot maneuvered the airplane back toward the departure airport. The pilot stated that, shortly after, at 500 ft, the airplane encountered severe icing conditions. He stated that he saw that the windows and wing leading edges were rapidly accumulating ice, that the engine began running roughly, and that the flight controls began feeling "sluggish." The engine surged with corresponding propeller vibrations. Both the pilot and the passenger stated that instrument meteorological conditions were present when the airplane was at 500 ft. The airplane could not maintain altitude and descended through 400 ft, and the pilot conducted a forced landing on snow-covered terrain about 5 miles from the airport. During the landing, the nose and right main landing gears sheared off due to impact with ground ice, and the fuselage then impacted terrain. Both occupants sustained serious injuries, and the left wing, horizontal stabilizer, and fuselage sustained substantial damage. The pilot stated that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. Even though a review of weather information for the area where the reported icing encounter occurred revealed no probability of icing at the reported time and altitude of the encounter, the airplane previously encountered icing conditions in the area and the pilot subsequently landed the airplane to evaluate the ice and the weather. The pilot then decided to take off and continue the flight toward the destination. It is likely that the pilot flew the airplane into an area of visible moisture at below freezing temperatures and that the airplane and propeller accumulated ice, which resulted in reduced aerodynamic performance and prevented the airplane from maintaining altitude.

Factual Information

On January 16, 2017, about 1520 Alaska standard time, a Piper PA-32-260 airplane, N4261T, was substantially damaged during a forced landing to snow-covered terrain about 5 miles south of the Pilot Point Airport (PNP), Pilot Point, Alaska. The airline transport pilot and sole passenger sustained serious injuries. The airplane was registered to a private individual and operated by Van Air Inc., Dillingham, Alaska, as a Title 14 Code of Federal Regulations Part 135 commercial on-demand passenger flight. A visual flight rules (VFR) flight plan was filed and activated. Day instrument meteorological conditions prevailed at the time of the accident. The flight departed PNP about 1505 destined for Port Heiden Airport (PTH), Port Heiden, Alaska. The pilot stated that the chartered passenger flight originated from Dillingham Airport (DLG), Dillingham, about 1350 destined for PTH with one passenger. While en route over the Pilot Point area, at an altitude of 800 feet and about 48 miles from the destination, the windshield started accumulating trace ice. The pilot landed the airplane at PNP and called the PTH village agent who reported the destination weather to be good with visibility 10 miles, clouds at 3,000 feet scatted, and no reported icing. The pilot asked the passenger if she knew anyone in Pilot Point that she could stay with that night, and she responded no and stated that she preferred to return to Dillingham if the airplane could not make it to the destination. The pilot decided to take off and continue the flight toward the intended destination to "take a look," and if the weather deteriorated, he would return to Dillingham. According to the pilot, the airplane departed PNP and continued southwest at 800 feet. About eight miles south of PNP, the wind screen started to accumulate ice, so he maneuvered the airplane back toward the north as planned. The passenger stated that after departing PNP, the visibility deteriorated, and the airplane was in clouds or fog after it turned around, and the engine did not sound right. The pilot stated that the aircraft began accumulating light structural ice and the engine started "running rough." He turned on the carburetor heat and engine performance was restored briefly. About 6 miles south of PNP at 500 feet, severe icing and visibility below 1 mile was encountered. The flight controls became sluggish, all the windows started icing over rapidly, and the engine surged with strong propeller vibrations. The airplane would not maintain altitude and descended through 400 feet. The pilot performed a forced landing on an easterly heading near the King Salmon River and Ugashik River confluence. During the landing sequence, the right main landing gear and the nose landing gear sheared off due to impact with ground ice. The fuselage, right wing, and right horizontal stabilizer sustained substantial damage. (Refer to figure 1.) The pilot and passenger sustained serious injuries during the impact and successfully egressed the airplane. Together they operated the Emergency Locator Transmitter, a mobile marine radio and the strobe light to effect rescue. The passenger, using her cell phone, called the Federal Aviation Administration Flight's Service Station in Dillingham to report the accident. A U.S. Coast Guard MH-60 helicopter extracted the survivors from the remote location about 1830. The closest weather reporting facility is PNP, about 5 miles north of the accident site. At 1521, an aviation special weather report (SPECI) stated in part: wind from 140 degrees at 5 knots; sky condition, overcast at 1,600 feet; visibility 1 ¾ statute miles in light snow; temperature 7°F; dewpoint 1°F; barometric pressure 29.23 inches mercury. A review of the Alaska Aviation Weather Unit graphic forecast charts indicated marginal VFR conditions along the route of flight with no significant icing or turbulence forecast. There were no published pilot reports (PIREPs) of icing conditions in the area. Also, the pilot stated that he obtained weather information from National Weather Service online services and determined no significant weather was forecast. The pilot stated that there were no preimpact mechanical failures or malfunctions with the airframe or engine that would have precluded normal operation. Figure 1. N4261T PA-32-260 wreckage at the accident scene.

Probable Cause and Findings

The pilot's continued flight into known icing conditions, which resulted in structural icing and a forced landing on icy, snow-covered terrain.

 

Source: NTSB Aviation Accident Database

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