What happened
On June 22, 2007, a mid-air proximity incident occurred at Frankfurt Airport involving a Boeing 747-400 and a Pilatus P3-05. The Boeing aircraft was on final approach to runway 25R when it encountered the Pilatus aircraft, which was operating under Visual Flight Rules (VFR) on a flight from Aachen to Würzburg. The minimum separation between the two aircraft was recorded at 0.6 NM horizontally and 300 ft vertically.
During the flight, the pilot of the Pilatus aircraft encountered a bank of clouds while over the Taunus region. In an attempt to avoid the cloud cover, the pilot maneuvered southeast but subsequently entered the clouds. The pilot reported that once inside the cloud layer, maintaining control of the aircraft's altitude and heading became difficult, and focus was primarily directed toward basic flight stabilization. After locating a break in the clouds that revealed the terrain, the pilot maneuvered the aircraft in a full circle within the opening. Upon noticing the proximity of Frankfurt Airport, the pilot turned east to exit the control zone as quickly as possible.
The investigation
The BFU investigation examined radar recordings from the air traffic control service and radio communications. The radar data confirmed the eastward flight path of the Pilatus aircraft. Audio recordings of the radio transmissions revealed that the air traffic controller issued a traffic information alert to the Boeing 747-400 crew regarding the presence of the Pilatus aircraft at 11:11:36. Shortly thereafter, at 11:11:43, the Boeing crew requested and received clearance to turn left. Following the passing of the Pilatus aircraft, the Boeing 747-400 returned to the glide path to continue its approach to runway 25R.
Findings
- The primary contributing factor was the loss of situational awareness and flight control by the pilot of the Pilatus aircraft after entering cloud cover.
- The pilot of the Pilatus aircraft was unable to maintain precise altitude and heading while navigating through a cloud layer.
- There was no radio communication established between the Pilatus aircraft and Frankfurt Tower during the event.
- No injuries or damage to either aircraft were reported.