What happened
On November 3, 2018, an Agusta A109E helicopter, registration PP-MTX, was performing a private flight from the Juquehy Baleia Helipad in São Sebastião to the HBR Helipad in Osasco. The flight, which included the pilot and four passengers, encountered deteriorating meteorological conditions during the en-route phase. As the aircraft entered a region characterized by thunderstorms, heavy rain, and cumulonimbus clouds, it collided with a forested area near the Quatinga district in Mogi das Cruzes, São Paulo. The impact resulted in the destruction of the aircraft and the death of all five occupants.
The investigation
CENIPA's investigation established that the aircraft was in a valid operational state, with all engines functional at the time of impact and the aircraft within weight and balance limits. Radar and satellite imagery confirmed the presence of intense precipitation and significant thunderstorm activity over the accident site. Analysis of the Cockpit Voice Recorder (CVR) revealed that the pilot was aware of the degrading weather and that the flight was being conducted in clouds and rain. However, the investigation noted that after the pilot decoupled the NAV mode, the aircraft experienced significant fluctuations in engine power, heading, and altitude, eventually leading to a loss of control in flight.
Findings
- Adverse meteorological conditions: The presence of cumulonimbus clouds and thunderstorms led to the unintended entry into IMC (Instrument Meteorological Conditions).
- Insufficient pilot experience: The pilot had only 8 hours of night VFR experience on this specific equipment, which contributed to a low perception of risk and flaws in decision-making.
- Control skills and decision-making: The pilot failed to adequately assess the operational implications of the weather degradation, leading to the decoupling of the NAV mode and subsequent loss of control.
- Spatial disorientation: Evidence suggested the pilot may have experienced visual illusions or spatial disorientation due to the prevailing flight conditions.
Safety action
CENIPA issued several recommendations to the Brazilian National Civil Aviation Agency (ANAC), including:
- Clarifying training and endorsement requirements for the A109E model.
- Assessing the need for mandatory night VFR training for specific endorsements.
- Establishing clearer guidelines for pilots to reacquire recent experience, particularly regarding night flight requirements.
- Disseminating lessons learned from this accident to civil aviation training centers.