What happened
On August 6, 2010, a Fuji FA-200-180AO, registration PH-BZN, entered the Schiphol local control area without permission or radio contact with air traffic control. The aircraft, a small red-and-white propeller plane, flew through the controlled airspace, causing two separate near-collision incidents with commercial airliners.
At approximately 10:30 AM, the crew of a Boeing 777-200, flight KL592, flying at 2,000 feet, encountered the light aircraft. The crew received a series of TCAS warnings, including a resolution advisory to climb. During the maneuver, they observed the PH-BZN passing approximately 100 feet below them.
Shortly thereafter, a second incident occurred involving flight BCY216D, a BAe Avro RJ85. While on approach, the crew also received TCAS warnings and was forced to abort their final approach and climb to 3,000 feet to maintain separation from the unidentified aircraft. Due to the unpredictable path of the PH-BZN and the lack of radar identification, air traffic controllers were forced to divert all traffic intended for runway 18R to runway 27 to ensure safety.
The investigation
Investigators analyzed cockpit voice recordings, TCAS data from the commercial aircraft, and radar plots from Air Traffic Control Netherlands (LVNL). Radar data showed the PH-BZN appearing near Lelystad and moving through the Schiphol CTR, despite the crew's claims that they had flown a different route and remained outside the controlled area.
Technical analysis of the TCAS computer from the Boeing 777 confirmed that the collision warnings were triggered by the specific transponder code assigned to the PH-BZN. The investigation also noted that while the aircraft was visible on primary radar, it lacked a four-digit transponder code and altitude information on the controllers' screens.
Findings
- The PH-BZN operated within the Schiphol controlled airspace without authorization or two-way radio communication.
- The aircraft's transponder was in standby mode and utilized older software, which prevented air traffic controllers from identifying the aircraft or seeing its altitude.
- The PH-BZN came so close to commercial traffic that TCAS resolution advisories were triggered, necessitating emergency maneuvers by both airliners.
- The crew of the light aircraft failed to notify air traffic control of their presence or exit the controlled airspace after the first encounter, significantly increasing the risk to other aircraft.