What happened
On July 1, 2005, at 07:45, a near-collision occurred near the Villefranche aerodrome within the Lyon TMA 4 Class C airspace. An ATR 42-500, operating a scheduled passenger flight, was descending to flight level 90 along a 120-degree magnetic track. While transitioning through clouds, the crew observed a Robin DR 400-160 approximately 300 feet above them. The crew reported the encounter to air traffic control immediately after the event, noting they had no time to perform an avoidance maneuver. The aircraft's onboard anti-collision system failed to detect the light aircraft.
At the time, the Robin DR 400-160, operated by a flying club, was conducting a cross-country flight. Due to weather conditions, the pilot had been descending from flight level 95 toward flight level 75. The pilot did not observe the ATR 42 during the encounter.
The investigation
The investigation established that the Robin DR 400-160 had entered Class C airspace without authorization. Air traffic controllers managing VFR traffic had no radio contact with the light aircraft, and neither the VFR controller nor the ATR 42 controller had secondary radar contact with the aircraft. While primary radar contact was established, controllers could not determine the altitude of the Robin DR 400-160. The aircraft was eventually identified through radar data and coordination with military controllers.
Investigators examined the pilot's navigation tools and found he was using a 1/500,000 scale aeronautical chart from the IGN. This specific chart included a warning not to use it above certain altitudes, but it did not display the Lyon TMA 4 airspace. Consequently, the pilot was unaware of the airspace boundaries.
Findings
Several contributing factors led to the risk of collision:
- The pilot failed to use the transponder, which prevented air traffic controllers from maintaining secondary radar contact and prevented the ATR 42's anti-collision system from detecting the aircraft.
- The pilot had an insufficient understanding of the limitations of the aeronautical chart being used, which resulted in an unintentional intrusion into Class C airspace.
- The pilot demonstrated a reluctance to contact air traffic control services, having not established radio contact since departure from Epernay.
- The pilot believed that contacting controllers was not regulatory required based on his perceived position.