Accident
On 23 June 2014 at 1522 hrs, the German Federal Bureau of Aircraft Accident Investigation (BFU) was informed by the Bundeswehr (German Armed Forces) that a collision had occurred between a civil Learjet 35A and a German Air Force Eurofighter during aerial target demonstrations. The Learjet was operated by a civil operator specializing in manned aerial target demonstrations. It had taken off from Hohn Airport and initially flown with a southern heading under Instrument Flight Rules (IFR). At the time of the accident, the Learjet had changed to Visual Flight Rules (VFR) and was flying in airspace E with a northern heading.
A formation of two Eurofighters had taken off from Nörvenich Air Base with the order to conduct a so-called Renegade mission, which involved intercepting, identifying, and accompanying the unknown civil aircraft to a military airport. After the collision with a Eurofighter, the Learjet crashed to the ground. The pilots of the Learjet suffered fatal injuries, and the aircraft was destroyed. The pilot of the Eurofighter managed to land the severely damaged airplane at Nörvenich Air Base.
Investigation
According to the Law Relating to the Investigation into Accidents and Incidents Associated with the Operation of Civil Aircraft (FlUUG), accidents and incidents involving civil and military aircraft are investigated under the responsibility of the BFU. The BFU immediately deployed a team of five investigators to the accident site, supported by the Directorate Aviation Safety of the German Armed Forces (AbtFlSichhBw).
Probable Cause
The investigation identified the following causes:
Immediate Causes:
- During positioning for the intervention, the collision risk due to unexpected manoeuvres of the intercepted airplane was not sufficiently taken into consideration.
- The Learjet crew did not take into account the risks due to possible limitations of the field of vision and the distraction by using the computer when deciding about the task distribution. Due to insufficient situational awareness during the intervention, the Learjet crew continued the turn with an excessive bank angle despite the loss of visual contact with the Eurofighter flying at the inside of the turn.
Systemic Causes:
- The operator had not specified in detail how the crew should distribute their tasks during Renegade exercises.
- Neither the operator commissioned to conduct the aerial target demonstration nor the Air Force had sufficiently described the Renegade training nor had a commensurate risk analysis been done.