ANC17FA010

The non-instrument-rated private pilot and three passengers departed from an airport along a lakefront in an airplane not equipped or certified for flight into known icing conditions. A couple of minutes after the airplane departed, a pilot who was descending to land at the departure airport spoke with the accident pilot. The pilot of the descending airplane told the accident pilot that the tops of the clouds were about 2,000 ft. The accident pilot replied, "looking good under here, I'm gonna keep going." No further radio transmissions were received from the accident pilot. When the airplane failed to arrive at its intended destination, a search was launched. The day following the accident, airplane debris and personal items that were positively identified as belonging to the occupants of the airplane were found floating on the surface of the lake. The debris indicated that the airplane impacted the surface of the lake. Despite an extensive search, neither the occupants nor the airplane have been recovered, and, due to the depth of the lake, a recovery mission is unlikely. Weather camera images, surface weather observations, and upper air observations indicated that the weather conditions at the time of the accident likely included freezing fog and mist, low visibilities and ceilings, and moderate or greater icing conditions in the clouds covering the accident area. Therefore, the accident flight likely encountered instrument meteorological conditions shortly after departure and rapidly began accumulating structural and/or induction icing. However, because the airplane was not available for examination by investigators, the possibility of mechanical failure or malfunction could not be ruled out.

The airplane was manufactured in 1971 and equipped with a Lycoming O-360 series engine. The airplane was not equipped or certified for flight into known icing conditions. No airframe or engine logbooks were located for the accident airplane. On December 7, 2016, about 0935 Alaska standard time, a wheel-equipped Piper PA-28-180 airplane, N8648N, impacted the open waters of Lake Clark shortly after takeoff from the Port Alsworth Airport (PALJ), Port Alsworth, Alaska. The noninstrument-rated private pilot and three passengers are missing and presumed to have sustained fatal injuries. The airplane was not recovered and is presumed to have sustained substantial damage. The airplane was registered to a private individual in Port Alsworth, and the pilot had rented the airplane for the 14 Code of Federal Regulations Part 91 visual flight rules cross-country personal flight. Visual meteorological conditions prevailed at the airplane's point of departure, but instrument meteorological conditions were reported along the flight's anticipated route. The flight departed PALJ about 0930 with a destination of Merrill Field Airport (PAMR), Anchorage, Alaska. No flight plan was filed for the flight. During a telephone conversation with a National Transportation Safety Board (NTSB) investigator on December 8, a friend of the pilot and passengers reported that the three passengers were part of a family traveling to Anchorage to meet up with other family members. They were originally scheduled to travel on a scheduled air carrier flight on the day of the accident, but canceled their reservations and elected to fly to Anchorage with the pilot instead. Another family member departed for Anchorage aboard the scheduled air carrier flight. A pilot who was completing a flight from Anchorage to PALJ about the time of the accident reported speaking with the accident pilot a couple minutes after the accident airplane departed from PALJ. He told the accident pilot that the tops of the clouds were about 2,000 ft and that, from his perspective, it looked open at Miller Valley, which is located about 10 miles northeast of PALJ along the northern shore of Lake Clark. The accident pilot replied, "looking good under here, I'm gonna keep going." No further radio transmissions were received from the accident pilot. When the airplane failed to arrive in Anchorage, family members and friends of the passengers reported the airplane overdue. An alert notice was issued by the Federal Aviation Administration (FAA) at 1501 on December 7, and an extensive search was launched. According to the airplane's owner, the airplane was equipped with a 406 MHz emergency transmitter locator, but no signal was received by search personnel. On December 8, about 1530, searchers located personal items floating about 11 miles northeast of the airport in Lake Clark that were later positively identified as belonging to the occupants of the airplane. Also recovered were three airplane landing gear wheelassemblies, a co-pilot (right side) seat, and cargo from the airplane. The rest of the airplane was not located, and it is presumed to have sunk in Lake Clark. The official search was suspended by the Lake Clark National Park and Preserve and the Alaska State Troopers on December 12, 2016. Family friends and volunteers continued to search for the missing airplane. To date, the remains of the pilot have not been located; therefore, no pathological or toxicology information exists. At the time of his last medical examination, the pilot reported no medical concerns, and no significant issues were identified by the aviation medical examiner. The closest official weather station was at PALJ, located about 8 miles southwest of the accident site. PALJ used Aviation Paid Weather Observers (A-Paid) who are individuals trained by the National Weather Service and/or the FAA and stationed in locations where the NWS has determined that it is necessary to take weather observations to help provide NWS forecast responsibilities. A-Paid observers are certified by the NWS to take surface observations (that is, hourly reports of temperature, dew point, estimated cloud cover, estimated visibility, pressure, weather, and wind direction and speed) using equipment provided by the NWS. These observers are compensated for their work on a per-observation basis. Between December 5 and December 7, there were a total of four observations taken by the A-Paid observer at PALJ. The only observation from the day of the accident was timestamped 1459 and stated in part: wind from 140° at 5 knots, 7 miles visibility, overcast ceiling at 500 ft above ground level (agl), temperature 3°F, dew point 0°F, and altimeter setting 30.18 inches of mercury. Iliamna Airport (PAIL), Iliamna, Alaska, was the next closest official weather station, located 40 miles southwest of the accident site. PAIL had an Automated Surface Observing System (ASOS); the reports were supplemented by air traffic controllers. At 0911, a METAR from PAIL reported in part: wind from 360° at 13 knots with gusts to 23 knots, 10 miles visibility, overcast ceiling at 1,100 ft agl, temperature of -3°C, dew point temperature of 1°F, and an altimeter setting of 30.17 inches of mercury. At 0953, a METAR from PAIL reported in part: wind from 360° at 16 knots with gusts to 22 knots, 10 miles visibility, overcast ceiling at 1,200 ft agl, temperature of -3°F, dew point temperature of 1°F, and an altimeter setting of 30.16 inches of mercury. The FAA had a weather camera at Lake Clark Pass located about 8 miles east-northeast of the accident site that took images facing the accident location. The reference image provided by the FAA for interpreting the weather camera's images is shown in Figure 1. Figure 1: FAA weather camera reference image The image shown in Figure 2 was taken at 0941. Although slightly dark due to the sun not rising until 1007 (about 32 minutes after the accident occurred), the visibility can still bedistinguished as limited. Figure 2: 0941 FAA weather camera image The image shown in Figure 3 was taken at 0951 and more clearly shows the limited visibility. Figure 3: 0951 FAA weather camera image The closest official upper air sounding to the accident site was from King Salmon, Alaska, (PAKN), located 124 miles southwest of the accident site at an elevation of 46 feet. The 0300 PAKN sounding indicated a conditionally unstable layer between the surface and 750 feet with a stable layer from 750 feet through 3,250 feet. An inversion (increase in temperature with height) was located immediately above the surface to 2,488 feet and this inversion would have kept any clouds that formed below the inversion in place if the background wind environment was relatively light. With the relative humidity greater than 80% from the surface to 10,000 feet, the complete Rawinsonde Observation program (RAOB) indicated that clouds were likely from the surface through 10,000 feet. Moderate or greater icing conditions were indicated by RAOB in the cloud cover between 750 feet and 6,500 feet. A detailed meteorology study is located in the public docket for this accident. The pilot, age 25, held a private pilot certificate with an airplane single-engine land rating. His most recent third class medical certificate was issued on February 1, 2013, and contained the limitation, "must wear corrective lenses." A logbook belonging to the pilot was recovered from the waters of Lake Clark during the search for the airplane. The last entry, dated November 9, 2016, was for a flight in the accident airplane. The total flight time listed in the logbook was 257.2 hours. The airplane is presumed to have sustained substantial damage during impact with the open waters of Lake Clark shortly after takeoff. Due to the depth of the lake, about 500 ft in some locations, there are no search and recovery efforts planned at the time of this report.