What happened
On January 31, 1998, an EMB 810C Sêneca, registration PT-REZ, departed Londrina, Brazil, on an IFR flight plan destined for Cascavel. During the flight, the crew requested to change their flight rules to VFR and proceed to Toledo, Brazil, at FL 065.
As the aircraft approached Toledo, the crew was unable to contact the local radio station because it was outside of its operating hours. During the approach, the aircraft collided with trees at the Maripá Farm, approximately 1,000 meters from the runway threshold of Toledo. The impact occurred while the aircraft was in a level attitude and cruise configuration. The accident resulted in three fatalities (both pilots and one passenger) and one injury (light) to the remaining passenger. The aircraft was a total loss.
The investigation
CENIPA's investigation established that the crew was attempting a visual approach under highly unfavorable meteorological conditions, including heavy rain and restricted visibility. The investigation found that the crew was using a portable GPS unit as their primary means of navigation, despite being unfamiliar with the device.
Furthermore, the investigation revealed a significant altimetry error. The aircraft's altimeter was set to the standard 1013 hPa, while the local pressure at the nearest operational airport was 1008 hPa. This discrepancy caused the altimeter to indicate an altitude approximately 140 feet higher than the actual altitude. The crew also attempted an approach via the western sector of the airfield, an area known for terrain depressions, which likely contributed to the collision with the treetops.
Findings
- Improper use of navigation equipment: The crew relied on a portable GPS as a primary navigation source despite a lack of familiarity with the device.
- Altimetry error: The failure to update the altimeter to the local QNH resulted in a 140-foot altitude error.
- Inadequate flight planning: The crew planned a VFR flight to a destination where they were unaware of the prevailing weather conditions.
- Human factors: The pilot's excessive confidence in his regional knowledge and professional experience, combined with the co-pilot's complacency, led the crew to descend under instrument conditions while operating under VFR authorization.
- Operational errors: The crew intentionally violated VFR regulations by flying under IFR conditions and descending below minimum altitudes.
- Adverse weather: Heavy rain and low visibility prevented the crew from perceiving the proximity of the terrain.