Aviation Investigation A17O0264

Collision with terrain

Updated on 21 December 2017

The following update contains facts that the TSB has been able to validate at this time. It contains no conclusions about the factors that contributed to the occurrence. The final investigation report will include an analysis of all relevant factors and provide the Board's findings.

The occurrence

On 14 December 2017, a helicopter Aerospatiale AS 350 B-2, registered to Hydro One Networks Inc, transporting 3 linemen and 1 pilot, crashed near Tweed, Ontario. All four occupants sustained fatal injuries. The TSB is investigating.

What we know

  • The linemen were conducting maintenance work on high-power transmission lines.
  • As part of the work being conducted, a few bags used for carrying tools and supplies were carried externally on a platform extending out of the right side of the fuselage. These bags, when carried externally, are normally attached with double-lock carabiners.
  • Shortly before the accident, the pilot picked up the 3 linemen at the base of a tower and was transporting them to a nearby staging area.
  • While nearing the staging area, one of the bags that was being carried externally blew off the platform and, along with its attached carabiner, struck the tail rotor.
  • Shortly thereafter, while the pilot was attempting to land, the helicopter departed from controlled flight, all 3 passengers became separated from the helicopter while it was still airborne. The helicopter subsequently crashed nearby.
  • The weather at the time of the accident was suitable for this type of operation and is not considered a factor.
  • The helicopter was not equipped with, nor was it required to carry, a Cockpit Voice Recorder (CVR) or a Flight Data Recorder (FDR). However, we have recovered a GPS, which will help with our investigation.

Progress to date

  • We have obtained initial eyewitness statements from the Ontario Provincial Police. The team is conducting follow-up interviews with selected witnesses.
  • Investigators have taken photographs of the wreckage and accident site.
  • Examination of the aft seatbelts found that 2 of the 3 passengers seatbelts were unfastened.
  • We have found a heavily damaged white canvas bag, with a damaged carabiner attached, and the tip of a tail rotor blade over 600 meters away from the crash site.
  • The helicopter was sent to the TSB Engineering Laboratory in Ottawa to examine the helicopter systems like flight controls and engines in a controlled environment.

Next steps

In the coming days and weeks, the team will:

  • Review the helicopter maintenance records, pilot training, qualifications and proficiency records.
  • Review operational policies and procedures and regulatory requirements.
  • Conduct interviews with family, witnesses, the helicopter operator and others who may provide additional information useful to the investigation.
  • Examine previous occurrences involving the Aerospatiale AS 350 B-2's, and subsequent safety action taken in Canada, the United States and other jurisdictions.

Map of the area


Photo of Peter Rowntree

Peter Rowntree has 26 years of civil aviation experience. He joined the TSB in November 1997 as an investigator/technical specialist in the TSB Air Investigations Ontario Regional Office, in Richmond Hill, Ontario. Prior to joining the TSB, he worked as an aircraft maintenance supervisor in the arctic for a major Canadian air carrier. During that time, he maintained and supervised the maintaining of different aircraft types, from small aircraft to the larger commuter and jet aircraft. Since joining the TSB, Mr. Rowntree has participated in numerous investigations and several major TSB investigations. He has also assisted numerous foreign accident investigation agencies in their work abroad.


Link to the TSB Flickr page

See more high resolution pictures on the TSB Flickr page.

Transportation Safety Board 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.


Safety communications

Aviation Safety Advisory A17O0264-D1-A1: Unsecured Cargo and Unrestrained Passengers in Helicopters
Read the aviation safety advisory

Media advisories

TSB will provide a news briefing on its investigation into the helicopter accident near Tweed, Ontario
Read the media advisory


TSB will provide a news briefing on its investigation into the helicopter crash that occurred near Tweed, Ontario
Read the media advisory

Deployment notices

TSB deploys a team of investigators to a helicopter accident near Tweed, Ontarioa
Read the deployment notice