What happened
On May 18, 2023, at 16:20 local time, a Cessna 560XL, registration EC-KOL, operated by Gestair, was climbing through 4,000 ft within the Madrid TMA. The aircraft was performing an IFR flight from Cuatro Vientos to Sevilla with two pilots and seven passengers on board. During the climb, air traffic controllers alerted the crew to the presence of another aircraft and instructed them to turn to a heading of 120 degrees.
Shortly after, the crew of the Cessna 560XL reported a TCAS RA (Resolution Advisory). The aircraft performed an evasive maneuver, descending approximately 300 ft to maintain separation. Simultaneously, a Piper PA28 161, registration CS-ECV, was operating a private VFR flight at 4,200 ft. The minimum separation between the two aircraft reached 0.6 NM horizontally and 200 ft vertically. The pilot of the Piper PA28 161 was unaware that a loss of separation had occurred.
The investigation
Investigators examined radar tracks, GPS data, and communications between the aircraft and Madrid TMA controllers. The investigation revealed that the Piper PA28 161 had entered Class A airspace (sector TMAD-22) without authorization. Radar traces showed the aircraft had been flying at 4,000 ft, penetrating the controlled airspace while returning to Cuatro Vientos. The pilot stated they believed they were flying further west, in a different sector.
Regarding air traffic control, investigators found that the controllers in sectors LECMWDN and LECMRSN had limited situational awareness. The controllers' radar screens were configured with filters that obscured the presence of the VFR traffic. Additionally, while the Cessna 560XL crew reported the TCAS RA, they did not explicitly communicate that the conflict had been resolved, and the controllers continued providing instructions without confirming the safety of the maneuver.
Findings
- The primary cause of the incident was the unauthorized entry into Class A airspace due to improper flight planning by the pilot of the Piper PA28 161.
- The controllers' situational awareness was degraded by inadequate radar screen configuration (specifically the lower altitude filters).
- There was a lack of standardized communication regarding the resolution of TCAS alerts between the crew and ATC.
- The Cessna 560XL and Piper PA28 161 sustained no damage, and all persons on board were uninjured.