Language selection

Air transportation safety investigation A19F0176

This is the summary of a class 5 occurrence to which TSB investigators deployed. The investigation is now closed.

Table of contents

Severe turbulence encounter

Air Canada
Boeing 777-233LR
Honolulu, Hawaii

The occurrence

On , an Air Canada Boeing 777-233LR (registration C-FNNH) was operating as flight ACA033 from Vancouver International Airport (CYVR), British Columbia, Canada, to Sydney Kingsford Smith Airport (YSSY), New South Wales, Australia, with 15 crew members and 269 passengers on board. The planned route was an almost direct routing over the Pacific Ocean with a planned flight time of 14 hours and 25 minutes.

The aircraft departed CYVR at 0750Footnote 1 and followed the flight-planned route. Before departure, the flight crew reviewed the forecast en-route weather. No significant weather was forecast along the route of flight until the segment near the equator, where isolated cumulonimbus clouds were forecast near the route of flight. In the area of the ADOWA waypoint, cumulonimbus clouds were forecast several hundred miles west of the planned track.

For the first few hours of the flight, the aircraft was flying in smooth air and clear of cloud. At approximately 1350, the cabin crew started preparing service carts in the galleys in order to begin 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 of the cabin crew were thrown into the ceiling of the cabin. In total, 37 people (31 passengers and 6 cabin crew) reported sprains, strains, cuts, and bruises.

The flight crew diverted to Daniel K Inouye International Airport (PHNL), Honolulu, Hawaii, United States, which was approximately 2 hours away. While en route to PHNL, the cabin crew and medical professionals who were among the passengers administered first aid. In preparation for landing, fuel was dumped and arrangements were made to have emergency medical services meet the aircraft at the airport.

The Transportation Safety Board of Canada (TSB) reviewed the aircraft’s digital flight data recorder, and there was no significant turbulence before or after the occurrence. Maintenance conducted a severe-turbulence inspection, and no faults were found. Some interior components and cabin furnishings were damaged where passengers and cabin crew had come into contact with them.

Media materials



This animation, developed for another investigation report, shows the effects the forces associated with severe turbulence can have on passengers who are wearing seat belts and those who aren’t.

Fasten your seatbelt – A15F0165 Severe Turbulence

Investigation information

Map showing the location of the occurrence


Photo of Jonathan (Jon) Lee

Jonathan (Jon) Lee is the Western Regional Manager for the Transportation Safety Board of Canada (TSB) in Edmonton, Alberta. He has been an aircraft investigator for 19 years, and has been managing the Edmonton office for eight of those years. He has been involved in approximately 50 investigations. Mr. Lee has also participated in foreign investigations that involve Canadian aerospace products. Working with the National Transportation Safety Board (United States), the Aviation Safety Council (Taiwan), Aviation and Railway Accident Investigation Board (South Korea), and the Aviation Accident Investigation Board (Mongolia) has made Mr. Lee appreciate the importance of the TSB’s role in global aviation.

Before working in accident investigation, Mr. Lee gained industry experience as a pilot in operations ranging from regional airlines and transcontinental cargo to medevac and flight instruction. He has flown over 35 types of aircraft and has accumulated 6500 flight hours. He maintains a valid and current airline transport pilot license.

Class of investigation

This is a class 5 investigation. Class 5 investigations are limited to collecting data, which are then stored in the modal database. If TSB investigators deployed to the occurrence site, a short description of the occurrence is posted to the TSB website once the investigation has been completed. These investigations are generally completed within 90 days. For more information, see the Policy on Occurrence Classification.

TSB investigation process

There are 3 phases to a TSB investigation

  1. Field phase: a team of investigators examines the occurrence site and wreckage, interviews witnesses and collects pertinent information.
  2. Examination and analysis phase: the TSB reviews pertinent records, tests components of the wreckage in the lab, determines the sequence of events and identifies safety deficiencies. When safety deficiencies are suspected or confirmed, the TSB advises the appropriate authority without waiting until publication of the final report.
  3. Report phase: a confidential draft report is approved by the Board and sent to persons and corporations who are directly concerned by the report. They then have the opportunity to dispute or correct information they believe to be incorrect. The Board considers all representations before approving the final report, which is subsequently released to the public.

For more information, see our Investigation process page.

The TSB is an independent agency that investigates air, marine, pipeline, and rail transportation occurrences. Its sole aim is the advancement of transportation safety. It is not the function of the Board to assign fault or determine civil or criminal liability.