Accident with an aircraft type Mooney M20J near Norrtälje Roslagen Airport

Summary in English

On 5 September 2025, a serious accident occurred involving a Mooney M20J aircraft,
SE-GXI, near Norrtälje Roslagen Airport. On board the aircraft were a pilot and an observer, both of whom were fatally injured.

The crew were taking part in an exercise for a Sea Information Group (SIG) within the framework of the activities of the Swedish Voluntary Flying Corps (FFK). After just over an hour of flying, SE-GXI returned towards Norrtälje Airport. For unknown reasons, a go-around was carried out at low altitude shortly before landing. Something then occurred which led to a loss of control of the aircraft, and shortly thereafter it impacted the surface of Lake Limmaren.

The investigation has been unable to clarify the entire sequence of events from the go-around until the aircraft struck the water surface. The most probable scenario is that the crew lost control of the aircraft, which then entered an uncontrolled attitude where the altitude did not permit recovery before water impact.

The technical investigations that were carried out showed no technical faults that could have contributed to the accident. The engine examination conducted by the manufacturer revealed no damage or irregularities that could have caused an in-flight engine malfunction. The technical investigations indicate that the accident was not caused by any technical fault in the aircraft or the engine.

Given that the flight was conducted with survival suits under the prevailing temperature conditions, the Swedish Accident Investigation Authority (SHK) assesses that there were conditions conducive to heat stress. Such stress can affect the crew’s physiological and cogni­tive ability to operate the aircraft. It is likely that this – in combination with an increased workload in connection with the go-around – was significant for the course of events.

The missions that FFK carries out on behalf of the Swedish Armed Forces are military in nature but are conducted within the civil aviation system and are not fully risk-assessed with regard to the nature of the missions. The investigation also shows that the support FFK provides to the Swedish Armed Forces is not regulated with sufficient clarity, despite previously identified needs for clarification in investigations by both SHK and the Swedish Armed Forces.

Causes of the accident

SHK has not been able to determine the cause of why the crew lost control of the aircraft.

Contributing factors were likely a combination of high workload in the final phase of the flight and heat stress that affected the crew’s performance capability.

An underlying systemic cause is that the requirements for the level of pilot licenses for FFK pilots are not adapted to the nature of the missions.

Safety recommendations

The Swedish Voluntary Flying Corps (FFK) is recommended to:

• carry out a systematic and documented risk analysis of the aircrews’ work environ­ment, and implement and follow up measures to reduce the identified risks. The analysis should form the basis for determining which level of pilot licenses are to apply to FFK’s pilots. (SHK 2026:16 R1)
• carry out a systematic and documented risk analysis of heat load in connection with flights using survival suits. The analysis should cover both operational and medical aspects and result in clear procedures and action plans to reduce the identified risks. (SHK 2026:16 R2)

The Swedish Armed Forces is recommended to:

• in cooperation with the Swedish Transport Agency and FFK, carry out an overarch­ing review of the regulations governing how FFK’s support to the Swedish Armed Forces is to be conducted. This review should include a clear clarification and formal establishment of the division of responsibilities as well as command and subordina­tion relationships regarding the Swedish Armed Forces’ use of FFK. (SHK 2026:16 R3)