L2024-02 Historic AircraftAccident at Räyskälä on October 16, 2024

The pilot and a passenger on board an SNJ-3 airplane departed on a post-maintenance check flight from Räyskälä aerodrome, Finland, on October 16, 2024, after a recent change of the airplane’s ownership.

The airplane took off at about 1205 h. The initial climb was normal, but about 100 m above ground level the engine failed, and the pilot initiated a steep right-hand turn in an attempt to return to the airfield for landing. During the turn, the airplane lost altitude rapidly, until it impacted ground after about one minute from the commencement of takeoff. Both occupants were fatally injured, and the airplane was destroyed by impact and post-impact fire.

Investigation determined that the engine failure resulted from fuel flow restriction. The airplane’s fuel selector valve was likely an original factory-installed component fitted with a cork seal that had apparently degraded over the years and therefore did not allow unrestricted fuel flow during takeoff. This, combined with considerable backlash in the operating linkage between the selector and valve, which resulted in the seal being in an incorrect position, led to a falling fuel level in the carburetor and engine stoppage. Investigation also stated that successful completion of a steep turn toward the runway at a low altitude after takeoff is practically impossible.

Although selector valve problems were known among recreational aviation communities, it is possible that all silent knowledge related to airplane operation was not transferred to the new pilot during ownership changes. The Federal Aviation Administration (FAA) of the United States had released a non-mandatory modification in order to eliminate the need of in-flight fuel tank switchover, but the modification had not been performed on the accident airplane.

The Safety Investigation Authority recommends that the FAA informs the owners and operators of the airplane type of risks related to the wear and aging of the fuel selector valve and its operating mechanism and of relevant risk management practices.

Corrigendum on 2.3.2026:

Revised paragraph on pages 39-40 of the Investigation Report:

In addition to stall speed and descent rate considerations it should be noted that takeoffs are generally performed into the wind. From this follows that headwind changes to tailwind during a turn to a direction opposite to that of takeoff, which leads to increase of ground speed.

Removed paragraph on page 45 of the Investigation Report about turn from headwind to tailwind.