What happened
On 27 April 2017, an Airbus A320, registration VT-IAR, operated by IndiGo, was en route from Kolkata to Hyderabad when the First Officer experienced a sudden medical emergency. Approximately 35 minutes after takeoff, while the aircraft was cruising, the First Officer attempted to drink water but experienced throat irritation. This was followed by physical stiffness in his limbs, blurred vision, and a loss of consciousness.
During the episode, the First Officer exhibited symptoms of a seizure, including body shaking and visible blood near the mouth, likely from a tongue bite. The Pilot-in-Command (PIC) immediately declared a "MAYDAY," notified Bhubaneswar ATC of the medical emergency, and initiated a diversion. To manage the situation, the Captain requested assistance from the cabin crew. The crew reclined the First Officer's seat, secured him with a shoulder harness to prevent accidental control interference, and administered oxygen via a Quick Donning Mask.
Despite the medical crisis, the Captain successfully managed the flight duties alone, performing a stabilized ILS approach and landing the aircraft safely at Bhubaneswar. The First Officer regained consciousness approximately 10 minutes after the onset of symptoms.
The investigation
AAIB India examined the medical history and operational circumstances of the flight crew. The investigation confirmed that the First Officer had been physically fit prior to the flight, having undergone a negative breath analyzer test and having had adequate sleep.
Medical evaluations conducted at various facilities, including Apollo Hospital and specialists in New Delhi, focused on the cause of the loss of consciousness. While neurological and brain imaging (EEG and CEM-MRI) returned normal results, the investigation noted the presence of Vitamin B12 and Vitamin D deficiencies, as well as unrelated findings of cholelithiasis and cystitis.
Findings
- The sudden incapacitation was most likely caused by an episode of seizure.
- The flight crew followed established company procedures for managing an incapacitated pilot, including securing the crew member and declaring an emergency.
- The aircraft was operated by appropriately licensed and qualified pilots.
- The medical event was unpredictable given the pilot's documented fitness prior to the flight.