What happened
On July 16, 2019, at approximately 08:36 UTC, two aircraft engaged in flight instruction experienced a loss of separation in the vicinity of the Sierra reporting point for Cuatro Vientos (LECU), Madrid. The first aircraft, a Cessna 172N, registration EC-GLO, was operating by Flyschool and was flying in a straight and level manner at 3,000 ft toward the Sierra reporting point.
While in flight, the crew of EC-GLO heard a radio transmission on an unofficial air-to-air frequency from a second aircraft, a Cessna 172RG, registration EC-HHX. The crew of EC-HHX, operated by Aerofan, reported being at 3,500 ft over the WG point of Getafe (LEGT). The crew of EC-GLO initially established visual contact with EC-HHX and notified the other aircraft of their relative position. However, due to the high-wing configuration of the Cessna 172N, the crew of EC-GLO subsequently lost visual contact with the higher-flying aircraft.
Seconds later, the Cessna 172RG flew over the Cessna 172N on a descending path, passing at a vertical distance of approximately 247 ft and a horizontal distance of about 92 m. There were no injuries to the two occupants on either aircraft, and no damage was sustained by either airframe.
The investigation
The CIAIAC investigation examined the flight paths, the operational manuals of the operators, and the visual approach charts for Cuatro Vientos. The investigation reviewed the flight of EC-HHX from a previous date, which revealed that the instructor had been following a pattern of descending from 3,50 and reaching 3,000 ft at the Sierra point, a practice consistent with the operator's manual but inconsistent with regional regulations.
Investigators also analyzed the Madrid TMA VFR circulation chart, which specifies a precaution to not exceed 3,000 ft in the visual sector south of the N-V highway. Furthermore, the investigation looked into the use of the 131.975 MHz air-to-air frequency, noting that while used by local flight schools for position reporting, this frequency is not officially published in the AIP.
Findings
- The primary cause of the incident was the failure of the crew of EC-HHX to adhere to the Madrid TMA VFR circulation chart, which prohibits exceeding 3,000 ft south of the N-V highway.
- The crew of EC-HHX failed to comply with the right-of-way regulations established in SERA.3210.
- A contributing factor was the discrepancy between the Aerofan Operations Manual and the official information published in the AIP Spain.
- The crew of EC-GLO lost visual contact with the other aircraft and did not communicate this loss of visual contact via radio.
- The crew of EC-HHX did not establish visual contact with EC-GLO at any point during the event.