Investigation Summary
The collision occurred at 37,000 feet (FL370). The Legacy 600 was on its delivery flight from the Embraer factory to the United States. According to the flight plan, the Legacy was supposed to fly at FL370 to Brasilia, then descend to FL360. However, the Brasilia controller cleared the Legacy to Manaus at FL370 without specifying the intermediate level changes. As the Legacy passed Brasilia, the ATC software automatically changed the aircraft's displayed altitude from 'cleared' to 'requested' without alerting the controller, leading them to believe the aircraft was at the correct (lower) altitude. Simultaneously, the Legacy's transponder was inadvertently switched to 'standby' mode, likely by the pilot's foot resting on the footrest near the unit, which disabled the Traffic Collision Avoidance System (TCAS). Consequently, neither aircraft received a resolution advisory before the impact.
Final Conclusions
The accident was caused by a combination of ATC errors and equipment configuration. Controllers failed to ensure the Legacy followed the flight plan's altitude changes and did not notice the loss of the transponder signal for several minutes. The Legacy pilots were found to have inadvertently disabled their transponder, which prevented TCAS from functioning. The NTSB emphasized that the primary failure was the ATC system's inability to maintain separation, while Brazilian authorities placed more weight on the Legacy pilots' failure to monitor their equipment status.
Video Analysis
Mid-air Collision: Gol Transportes Aéreos 1907 and ExcelAire N600XL — An analysis of the 2006 collision over the Amazon involving a Boeing 737 and an Embraer Legacy 600. The video examines air traffic control errors and the deactivation of the Legacy's transponder.
Watch on YouTube ↗If playback is blocked, the owner has disabled embedding — use the link above.
Systems & Failure Modes
TCAS (Traffic Collision Avoidance System)
A system designed to reduce mid-air collisions by communicating between aircraft transponders; it failed to provide warnings because the Legacy's transponder was off.
SSR (Secondary Surveillance Radar)
ATC equipment that relies on aircraft transponders to display altitude; it showed the Legacy at FL370 as a 'ghost' target without verified altitude.
RMU (Radio Management Unit)
The interface in the Legacy cockpit where the transponder was likely deactivated by accidental pilot contact.
Interesting Facts
- 01The Boeing 737-800 was less than three weeks old at the time of the crash.
- 02The Legacy 600 was on its maiden delivery flight to the United States.
- 03Both aircraft were equipped with TCAS, but it was inactive on the Legacy because the transponder was in standby.
- 04The collision occurred in a 'blind spot' of Brazilian radar coverage where radio communication was also difficult.
- 05All 154 people on Gol 1907 died, making it Brazil's deadliest aviation accident at the time.
Safety Actions & Advisories
TCAS Alerting Improvements
Source ↗The NTSB issued recommendation A-07-35, asking for enhanced aural and visual warnings to alert pilots if their TCAS or transponder becomes inactive.
ATC Software Updates
Brazilian authorities updated ATC software to prevent the automatic changing of altitude fields without controller confirmation.
Known Controversies & Unanswered Questions
CENIPA vs. NTSB Causal Findings
Reference ↗The Brazilian CENIPA report placed significant blame on the American Legacy pilots for deactivating the transponder, while the NTSB argued the pilots acted properly within the ATC instructions they were given and that ATC failure was the primary cause.