Occurrence
On 11 July 2019, an Air Canada Boeing 777-233LR (registration C-FNNH), operating as flight ACA033, departed Vancouver International Airport (CYVR), British Columbia, Canada, en route to Sydney Kingsford Smith Airport (YSSY), New South Wales, Australia. The aircraft carried 15 crew members and 269 passengers. The planned flight time was 14 hours and 25 minutes.
Pre-Flight and Initial Flight
Before departure, the flight crew reviewed the forecast en-route weather. No significant weather was forecast along the route until the segment near the equator, where isolated cumulonimbus clouds were predicted near the route. In the area of the ADOWA waypoint, cumulonimbus clouds were forecast several hundred miles west of the planned track.
The aircraft departed at 0750 and followed the flight-planned route. For the first few hours, the aircraft flew in smooth air and clear of cloud.
Turbulence Encounter
At approximately 1350, the cabin crew began preparing service carts in the galleys to start the snack service. The seatbelt sign was off. At 1400, the aircraft was near the ADOWA waypoint, 640 nautical miles southwest of Honolulu, Hawaii, United States, when it encountered severe turbulence at flight level 340 for 10 to 15 seconds. Several passengers and some cabin crew members were thrown into the ceiling of the cabin.
Injuries and Damage
A total of 37 people—31 passengers and 6 cabin crew—reported sprains, strains, cuts, and bruises. Maintenance conducted a severe-turbulence inspection, and no faults were found. Some interior components and cabin furnishings were damaged where occupants had come into contact with them.
Diversion and Aftermath
The flight crew diverted to Daniel K Inouye International Airport (PHNL), Honolulu, Hawaii, United States, approximately 2 hours away. While en route, cabin crew and medical professionals among the passengers administered first aid. Fuel was dumped, and arrangements were made for emergency medical services to meet the aircraft upon landing.
The Transportation Safety Board of Canada (TSB) reviewed the aircraft’s digital flight data recorder, which showed no significant turbulence before or after the occurrence.