What happened
On May 20, 2011, at approximately 09:30 UTC, a Boeing 737 (registration EI-DWC) operating as Ryanair flight RYR4593 departed Perugia Airport (LIRZ) for London Stansted. The aircraft was flying under Instrument Flight Rules (IFR) following a standard instrument departure (SID) via the LAKOX 6G route, climbing toward FL 110.
Simultaneously, a formation of four Tecnam P2002JF aircraft (registrations OH-TPI, OH-TPF, OH-TPG, and OH-TPH) was operating under Visual Flight Rules (VFR). The formation, flying under the callsign OH-TPI, had departed from Capua and was transiting the Perugia Control Zone (CTR) at 4,500 feet on a route from Todi to Fossombrone.
At 09:31 UTC, the crew of the Boeing 737 reported to the Perugia Tower that they had observed traffic approximately 1,500 feet above their current altitude. The Tower controller, after a brief hesitation, identified the traffic as a SIRA type aircraft at 4,500 feet. The crew of EI-DWC then reported that they had just passed 900 feet below the identified traffic.
The investigation
The ANSV investigation examined the coordination between the Perugia Tower (TWR) and the Perugia Approach (APP) controllers. The investigation noted that while the controllers' workstations were co-located, allowing for immediate verbal coordination, there was no documented evidence of specific coordination regarding this encounter.
The investigation also reviewed the flight plans and the airspace classification. The event occurred within a Class D airspace, where air traffic services are required to provide traffic information to both IFR and VFR flights. The investigation found that the planned route for the VFR formation was destined to conflict with the departure procedure of the IFR flight.
Findings
- The investigation established that no traffic information was provided to any of the aircraft involved in the encounter.
- The lack of traffic information prevented the pilots from adjusting their flight paths to maintain safety.
- A lack of effective coordination between the Tower and Approach control positions may have contributed to the event.
- There was a failure to properly apply procedures for the transfer of IFR control from the Tower to the Approach controller.