What happened
On April 22, 2005, at 11:41 UTC, a loss of separation occurred in the Prague TMA/CTR airspace between a charter flight, an A3CO operated by Eurofly S.P.A. (registration EEZ 1978), and an L 200 D Morava (registration OK-RMA) operated by Aeroklub Praha-Letňany.
The pilot of the OK-RMA was conducting an aerial photography mission over Prague. After departing from Letňany, the pilot requested a climb to 3,500 ft to fly south, east of the Vltava River. Simultaneously, the crew of EEZ 1978 was performing a VOR/DME approach to runway 31 at Prague/Ruzyně Airport.
During the approach, the horizontal separation between the two aircraft dropped to 0.87 NM, and the vertical separation decreased to only 200 ft. The crew of EEZ 1978 subsequently reported performing an ACAS RA maneuver to avoid the nearby traffic.
The investigation
The ÚZPLN investigation examined the actions of both flight crews, the air traffic controllers (ATCO), and the operational procedures in place. The investigation relied on radar information and radio communications between the aircraft and the Prague Approach (IEC APP Praha) and Ruzyně Tower (TEC LKPR).
Investigators found that while both flight crews and the air traffic controllers were properly qualified and competent, significant procedural failures occurred during the clearance process. Specifically, the investigation focused on the coordination between different sectors of the Prague control area and the management of aircraft transitioning between different airspace classes.
Findings
- The controller at Prague Approach (IEC APP Praha) authorized the OK-RMA to climb to 3,500 ft without considering that this change in altitude would move the aircraft from Class D into Class C airspace (TMA II LKPR).
- The controller failed to coordinate the altitude change with the adjacent Prague-Kbely (AEC APP Praha) sector.
- The controller did not account for the fact that the flight path of the OK-RMA would intersect with the approach path of EEZ 1978.
- The controller failed to ensure the required separation between IFR and VFR traffic when authorizing the climb.
- The controller provided incomplete traffic information to the OK-RMA crew regarding significant traffic in the area.