What happened
On April 20, 2004, at approximately 02:24 local time, an S-76A helicopter, registration PT-YBG, operated by Líder Táxi Aéreo, crashed near Macaé, Rio de Janeiro. The flight was a scheduled night maintenance mission intended to verify the functionality of the Electronic Attitude Display Indicator (EADI) system following recent maintenance.
After departing from Macaé Airport under visual flight rules (VFR), the crew retracted the landing gear and climbed to 700 feet. During the climb, the crew observed warning lights indicating that the front right and rear left doors were unlocked. Shortly thereafter, an audible and visual alarm for the landing gear being unseated also activated.
While the crew focused on investigating these cockpit warnings, the aircraft began a descent. The helicopter struck tree canopies before sliding approximately 75 meters into a marshy area near drainage channels. The impact was severe enough to cause the tail rotor assembly to detach and submerge in a nearby ditch. The commander escaped without injury, while the co-pilot and mechanic sustained minor injuries. The aircraft was a total loss.
The investigation
CENIPA's investigation focused on the sequence of events leading to the Controlled Flight Into Terrain (CFIT). Investigators analyzed the Cockpit Voice Recorder (CVR), which revealed that the crew was preoccupied with the door and landing gear warnings for approximately 42 seconds prior to impact.
The investigation also examined the operational pressures surrounding the flight. The commander had expressed discomfort regarding performing the mission at night due to limited night-flying experience. However, maintenance personnel and operations management pressured the crew to proceed to ensure aircraft availability for the following day. Furthermore, the investigation noted that the pilots lacked specific training for the EADI configuration used in this aircraft, which included altitude-based safety triggers for the landing gear alarms.
Findings
- Fixation of attention: The crew became hyper-focused on resolving the cockpit warnings, leading to a loss of situational awareness and a failure to maintain controlled flight.
- Improper task management: There was a lack of effective Crew Resource Management (CRM), characterized by a failure to assign specific roles (such as one pilot flying while the other checked instruments) and poor communication between the pilots.
- Operational pressure: The crew performed the night mission under pressure from maintenance and operations management, despite the commander's expressed reservations.
- Lack of preparation: No pre-flight briefing was conducted for this specific maintenance mission, and the crew did not review the daily maintenance logs prior to takeoff.
- Inadequate training: The crew lacked specific familiarity with the EADI safety settings and had limited experience with night operations in this specific aircraft type.