N185RNCessna A185E · 1968

On April 11, 2020, about 2025 Alaska daylight time, a Cessna A185E, N185RN, was substantially damaged when it was involved in an accident near D&C Fire Lake Flying Club Seaplane Base (D72), Eagle River, Alaska. Of the four occupants onboard, the pilot and one passenger sustained serious injuries, and two passengers sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations (CFR) Part 91 personal flight.

Due to the injuries sustained in the accident, the pilot had no recollection of the accident flight. The pilot-rated passenger, seated in the front right seat, reported they were returning home from the family’s cabin and the pilot began the initial descent about 5 miles north of Fire Lake. He said that the pilot’s intentions were to over fly the lake to inspect the landing area, followed by a left base turn, and a landing on the frozen lake to the north. He added that as they flew over the north side of the lake, on a southerly heading, the pilot began to maneuver the airplane for the approach to land and the engine suddenly lost all power, but the propeller continued to windmill. The pilot continued to fly the approach and set up to make an emergency landing. As he maneuvered the airplane to the left, he said, in part: “We are going down” which was immediately followed by the sound of the stall warning horn. The airplane subsequently struck a stand of trees and a powerline, and then pitched down violently and struck the ground in a nosed down attitude.

The pilot-rated passenger reported that immediately after regaining consciousness, moments after the accident, he realized that he had gasoline in his eyes and on his coat.

A witness on the ground reported that he observed the airplane fly over the northeast corner of the lake, and head south, at an altitude of about 600 ft. As the airplane passed overhead, he noted that the flaps were initially in the retracted position. He heard the power suddenly change from a mid-range cruise setting to an abrupt loss in power. He added that the propeller continued to windmill following the loss of engine power, and that once the airplane was about midway over the lake it banked to the southwest. He then recalled that the flaps had been extended and the airplane appeared to be in a forward sideslip momentarily. After briefly losing sight of the airplane, he witnessed it heading east toward the direction of the lake. A few seconds later he heard an airplane impact the trees and the ground.

The airplane came to rest in a residential yard in a near vertical position after impacting multiple trees and a powerline. The wings, fuselage, engine, and empennage were impact damaged. The landing gear appeared to be extended in the ski down position. All parts of the airplane were located at the accident site.

Federal Aviation Administration (FAA) inspectors that responded to the accident site reported that the outboard left wing leading edge had impacted the ground and that the right wing had not impacted the ground. They observed no fuel on the ground, no odor of fuel was noted at the scene of the accident, and there was no evidence of a post-crash fire. The empennage was separated but remained connected to the fuselage by the flight control cables. The left and right flap appeared to be positioned in the down (extended) position. The fuel selector was found set to the middle (BOTH) position. There were no propeller ground strike marks, and the propeller was damaged.

The FAA inspectors further reported that where the right wing connects with the forward pillar that the fuel line was pulled from the fuel tank. They added that they removed the left inboard fuel tank cap and observed that the fuel tank membrane was completely dry. Then they removed the left outboard fuel tank cap and observed that the tank membrane showed the presence of fuel. They dipped the left tank and the dip stick went to the outboard aft corner of the tank, which was the lowest point in the fuel tank due to the position of the airplane. A moisture mark was noted about 1.5 to 2 inches up on the stick when it was removed. They did not pull the fuel tank caps on the right tanks due to the position of the airplane.

First responders reported minimal evidence of a fuel spill at the accident scene upon arrival. During the recovery of the airplane wreckage the following afternoon, no fuel was found in either wing. Residual fuel was found in the fuel strainer that contained minor sediment and no blockages were found in the engine fuel lines. Examination of the airplane revealed no evidence of preimpact malfunctions or anomalies.

The pilot rated passenger reported they sumped the fuel tanks prior to the flight and no water or contaminates were noted. He said he was unsure of the quantity of fuel onboard before the flight because “they do not dip the tanks or visually check fuel levels; they rely on the fuel totalizer for the fuel quantity.” He was unsure when the last time fuel was added, but said the pilot usually flew to Birchwood Airport (BCV), Alaska to refuel. He did not recall the fuel quantity just before the accident and did not know of any mechanical problems prior to the accident.

A Garmin GPSMap 495 portable global positioning system (GPS) was recovered and subsequently download and analyzed. The downloaded data revealed that the airplane was last flown to BCV, the pilot’s reported usual refueling airport, on March 28, then flown to the family’s cabin, and the airplane then returned to Fire Lake that same day. On April 4, the airplane was flown from Fire Lake to the family’s cabin and back to Fire Lake. On April 11, the day of the accident, the airplane was again flown from Fire Lake to the family’s cabin, and the accident occurred while returning to Fire Lake. A total of about 4.1 flight hours had elapsed since the airplane had been flown to BCV, or any other intermediate stops between Fire Lake or the family’s cabin.

A J.P. Instruments (JPI) Fuel Scan, model 450, was recovered and subsequently downloaded at the NTSB's Vehicle Recorders Laboratory. The following preset parameters were recovered from the device:

Twin/Single Engine: “Single”

Fuel Units: “Gallons”

Tanks Size: “68”

Fuel Remaining: “7.7”

Fuel Used: “0”

The J.P.I model 450 Fuel Scan system is dependent on user input to provide correct indications of fuel used and fuel remaining parameters.

The airplane was configured with an 84-gallon total fuel capacity (78 usable). Each wing can hold 42 gallons (39 usable) of fuel, with about 3 gallons unusable fuel remaining in each wing after fuel exhaustion.

The airplane was equipped with a Continental IO-550-D engine, Fluidyne 3600 hydraulic wheel-skis, and a belly-mounted cargo pod. An airplane performance study was performed by the NTSB’s vehicle performance group. The group found that detailed airplane performance data for the Cessna A185E on hydraulic wheel-skis, with the Continental IO-550-D engine, do not exist. However, limited fuel burn data was found.

Supplemental Type Certificate (STC) SA00344WI, which facilitates the installation of the Continental IO-550-D engine in the Cessna A185E, reflects the following limitations regarding fuel flow at full throttle (2,700 RPM) for the airframe/engine combination: 24.9 gallons per hour (GPH) sea level, 22.6 GPH 4,000 ft., 19.2 GPH 8,000 ft., 17.1 GPH 12,000 ft. However, the throttle, propeller, and mixture settings used on the flights leading up to and the accident flight are unknown. Assuming the airplane had maximum usable fuel when it departed BCV, 4.1 flight hours before the accident, the engine had an average fuel consumption rate of about 19 GPH.

Title 14 CFR Part 91.151(a) defines the minimum fuel requirements for flight under day VFR. It states that no person may begin a flight in an airplane under VFR conditions unless (considering wind and forecast weather conditions) there is enough fuel to fly to the first point of intended landing and, assuming normal cruising speed, to fly after that for at least 30 minutes. The intent of the fuel reserve is to accommodate the unexpected: an incorrect forecast for winds aloft enroute, an unexpected and longer routing from air traffic control, etc.

To arrive at the destination airport with a 30-minute VFR fuel reserve, the accident airplane would have needed to burn fuel at a rate of about 17 GPH if all usable fuel was available for 4.1 hours of flight time.