What happened
On February 22, 2018, a Boeing 737-4B6, registration PR-SDU, operated by Sideral Linhas Aéreas, was performing a cargo flight from Brasília (SBBR) to Manaus (SBEG). During the climb phase, after passing through Flight Level 140, the commander experienced a sudden medical emergency. The pilot became unconscious, exhibiting tremors and excessive salivation.
At the time of the incident, the aircraft was operating under autopilot. The co-pilot immediately assumed control of the aircraft, leveled the flight at FL150, and coordinated with Air Traffic Services. After assessing the necessary fuel requirements, the co-pilot initiated a return to the origin airport. The aircraft landed safely at Brasília without any damage to the airframe, and both crew members remained uninjured.
The investigation
CENIPA investigators examined the cockpit voice recorder and flight data to reconstruct the sequence of events. The investigation focused on the medical aspects of the commander's incapacitation. Medical records revealed that the commander had a history of a meningioma (a tumor of the membranes surrounding the brain) in 2007, which had left a scar known as encephalomalacia.
Investigators also analyzed the crew's recent physiological state. The commander reported a period of inadequate rest following a night flight the previous day, noting difficulty sleeping during daytime hours. Additionally, medical personnel at the airport treated the commander for hypoglycemia upon landing. The investigation also looked into the regulatory framework regarding how medical examiners access a pilot's previous health inspection records.
Findings
- Pilot incapacitation was the primary event, characterized by a loss of consciousness lasting approximately twenty minutes.
- Fatigue may have contributed to the event, as the commander had experienced insufficient restorative sleep due to recent night operations.
- Inadequate nutrition (hypoglycemia) was identified as a potential physiological trigger for the medical episode.
- The presence of encephalomalacia (a brain lesion from a previous surgery) likely interacted with fatigue and low blood sugar to trigger the seizure-like symptoms.