What happened
On February 3, 2022, at approximately 11:51, a Textron 172N, registration TF-ABB, crashed into the Ölfusvatnsvík area of Lake Þingvallavat . The aircraft had departed from Reykjavík Airport (BIRK) at 10:38 with a pilot and three passengers. The flight was traveling along the south coast toward Þjórsárós before turning northwest toward the lake.
Onboard video footage captured during the descent indicates that while the engine was initially producing power, the engine power decreased, causing the aircraft to descend toward the water. Security camera footage from the area showed the aircraft flying at a very low altitude before performing a left turn and impacting the lake surface. Following the impact, a brief, distressed phone call was placed from a passenger's phone to emergency services.
The investigation
The RNSA investigation involved a complex underwater recovery operation. The aircraft was located by a side-scan sonar on February 4 at a depth of approximately 47 meters. An ROV later confirmed the identity of the wreckage. The aircraft was eventually recovered from the lake bed on April 22, 2022. During the recovery, investigators also retrieved a broken antenna located 35 meters from the wreckage.
Investigators examined the wreckage and recovered electronic devices. Data from memory cards within these devices were successfully retrieved and analyzed. The investigation also focused on the state of the aircraft's controls, fuel systems, and safety equipment. Tragically, the four occupants were found deceased in the lake several days after the aircraft was located.
Findings
Technical examination of the wreckage revealed that the fuel system was contaminated with water. Specifically, approximately 58 liters of water were found in the right fuel tank and 28 liters of water were found in the left fuel tank. This water contamination in the fuel was a critical factor in the engine power loss observed during the descent.
Other findings included:
- The aircraft's flaps were set to 30 degrees.
- The throttle was positioned at 4.0 cm of the 5.5 cm available.
- The carb heat was set to the ON position.
- The master switch and ignition switch were both in the OFF position.
- The emergency locator transmitter (ELT) was armed, but no signals were received following the crash.
- The pilot and the front-seat passenger were not using shoulder harnesses, and the rear passengers were likely not wearing seatbelts.
- The left window of the left door was slightly open.