What happened
On July 5, 1995, a Piper PA-28-236 Dakota, registration PH-DAK, crashed into a steep mountainside in the Eigental region of Lucerne, Switzerland. The aircraft, which had departed from Hilversum in the Netherlands for a private VFR flight to Buochs, was carrying three occupants. During the flight, the crew entered the Zurich TMA without prior authorization and subsequently contacted air traffic services.
While flying at FL 85, the crew requested permission to descend below the cloud layer. After receiving instructions from the Emmen tower to maintain 6000 ft, the aircraft began a descent. At approximately 10:46 UTC, the crew transmitted that they were passing 4500 ft in IMC (Instrument Meteorological Conditions). Shortly thereafter, the radar echo disappeared. The aircraft struck the terrain after clipping several trees, resulting in three fatalities and the total destruction of the aircraft.
The investigation
The investigation examined radar data, radio transcripts, and meteorological records. Investigators reviewed the actions of the air traffic controllers at both Zurich Delta and Emmen. The inquiry also looked into the pilot's flight preparation and the navigation error that led the aircraft toward the mountainside rather than its intended destination. The investigation noted that the controller at Emmen misheard the phrase "IMC" as "climbing," which led him to believe the aircraft was still operating under VFR conditions.
Findings
- The primary cause of the accident was the deliberate continuation of a VFR flight into IMC within mountainous terrain.
- The crew's flight preparation was inadequate for the weather conditions encountered.
- A navigational error occurred, as the crew appears to have confused the destination of Buochs with Alpnach.
- The crew provided misleading information to air traffic control, which prevented controllers from identifying critical safety risks.
- The air traffic controller at Emmen did not verify the actual weather conditions or the aircraft's flight rules (VMC/IMC) during the descent.