What happened
On December 6, 2017, a near-collision occurred near the TESEL waypoint within the Canarias Terminal Control Area (TMA). The incident involved two aircraft: a commercial ATR 72-212A, registration EC-MPI, operated by CANAIR, and a private PIPER PA28-181, registration EC-JMT, operated by the Real Aero Club de Tenerife.
The PIPER PA28-181 was conducting a visual flight rules (VFR) flight around the perimeter of Tenerife. Meanwhile, the ATR 72-212A was operating under instrument flight rules (IFR), having departed Tenerife North Airport (GCXO) on a standard instrument departure.
At approximately 15:18 local time, the two aircraft reached a point of extreme proximity. The horizontal separation between them was reduced to just 1.13 nautical miles, with a vertical separation of only 200 feet. While the pilot of the PIPER PA28-181 established visual contact with the larger aircraft and maintained separation, the crew of the ATR 72-212A was unaware of the other aircraft's presence.
The investigation
The investigation focused on the coordination between various air traffic control (ATC) sectors, including Tenerife North Approach, Tenerife South Approach, and the GCCCINB sector of the Canarias ACC.
Investigators found that the controller for the GCCCINB sector had coordinated the transfer of the PIPER PA2 8-181 directly to Tenerife North Approach, despite the aircraft being within the GCCCINB sector's responsibility. This deviation from the established Letter of Agreement (LoA) created a gap in situational awareness. Furthermore, the investigation revealed that a controller relief had occurred in the GCCCINB sector without following the standard ENAIRE checklist, leaving the incoming controller unaware of the full traffic situation in the area.
Additionally, the investigation noted that a Conflict Alert (VAC) was triggered at 15:18:09, yet there was no evidence that the GCCCINB controller attempted to contact other controllers to investigate the alert.
Findings
- The primary cause of the incident was that the GCCCINB sector controller failed to provide traffic information to the ATR 72-212A regarding the proximity of the other aircraft.
- Controllers failed to comply with the established Letter of Agreement regarding the proper procedures for transferring control of aircraft between agencies.
- A deficient shift handover following a temporary absence of the GCCCINB controller resulted in a loss of situational awareness regarding traffic in the sector.
- The incoming controller's attention was potentially compromised by a cognitive bias, as VFR traffic appeared in a different color on the radar screen, making it harder to prioritize.
Safety action
- REC 15/18: It is recommended that ENAIRE instruct controllers on the necessity of providing traffic information between IFR and VFR flights when trajectories are convergent and separation may reach minimum limits, in order to prevent potential TCAS alerts.