What happened
On October 1, 1997, at 21:45 local time, an Embraer 121 Xingu, registration PP-EHJ, crashed in a wooded area approximately 2.5 km from the runway threshold at Chapecó Airport (SBCH), Brazil. The aircraft, operated by the Air Service Division of the State of Rio Grande do Sul, was performing a mission to transport a team of five doctors for an organ retrieval operation.
The flight departed from Porto Alegre (SBPA) and was operating under instrument flight rules (IFR). During the approach to runway 29, the crew initially attempted the ECHO 1 procedure but aborted the landing after failing to establish visual contact with the runway. During a second attempt using the same procedure, the crew was informed by local radio of deteriorating weather, including rain and a ceiling of 600 feet. Despite the fact that the ECHO 1 procedure requires a minimum ceiling of 900 feet, the aircraft continued the approach. Shortly after, the aircraft struck the terrain with its wings level. The impact resulted in six fatalities among the passengers and two fatalities among the crew, with one passenger later succumbing to injuries at a hospital.
The investigation
CENIPA's investigation focused on the aircraft's systems, the meteorological conditions, and the crew's decision-making. Technical analysis of the wreckage showed that the engines were at high power during impact, suggesting the crew attempted to recover from a sudden loss of lift. The investigation ruled out mechanical failure, as all aircraft systems, including the Angle of Attack sensors, were functioning normally, and the engines were producing high power.
Investigators examined the meteorological data, which revealed significant wind variations. Just before the crash, the wind shifted from 290 degrees at 10 knots to 320 degrees at 20 knots. The investigation also looked into the crew's psychological state, noting the high-pressure nature of the organ transplant mission and the two-hour departure delay, which may have contributed to anxiety.
Findings
- The primary cause of the accident was likely the encounter with wind shear, specifically vertical downdrafts, which forced the aircraft into the ground.
- The crew demonstrated flight indiscipline by intentionally performing an approach below the established IFR minimums (600 feet ceiling instead of the required 900 feet).
- Deficient judgment played a role, as the crew failed to properly evaluate the deteriorating weather and did not divert to an alternate airport despite the unsafe conditions.
- The mission's urgency and the delay in departure likely induced anxiety, affecting the crew's decision-making process.
- The operator lacked an effective training program to prepare crews for handling adverse weather phenomena like wind shear.