A helicopter carrying offshore oil workers dropped suddenly from the sky and came close to hitting the water in a 2011 incident, the Transportation Safety Board of Canada has revealed.
An investigation released Thursday found that the Cougar Helicopters flight "inadvertently descended and came within seconds of striking the water" on July 23, 2011.
The board found that numerous problems, including crew errors, contributed to the near-crash, which resulted in the flight's captain being fired.
The aircraft — a Sikorsky S-92A — was the same as the one involved in a disaster off Newfoundland's east coast that killed 17 people in March 2009.
In the July 2011 incident, the chopper — which was carrying two crew and five passengers — left an offshore oil platform to head back to St. John's.
The TSB found that the helicopter effectively dropped like a stone, coming within 11.5 metres — or about 38 feet — of the Atlantic Ocean.
The investigation identified numerous operational, procedural and training problems that all contributed to the incident.
"During the departure, the captain made a large, rapid aft control input just prior to activating the go-around mode, causing the helicopter to enter a nose-high, decelerating pitch attitude in cloud," the TSB said in a statement.
The chopper started dropping when it fell below the minimum control speed, with problems then compounded when other things went wrong.
"The captain, subtly incapacitated, possibly due to spatial disorientation, did not take action to recover from the descent in a timely manner," the TSB said.
153-metre drop in 32 seconds
Rather than jumping into action, the first officer did not take control of the aircraft, as specified in Cougar's training. The board said the first officer had been "lacking confidence in his abilities to recover from the inadvertent descent."
The TSB found the chopper dropped 153 metres (503 feet) in 32 seconds.
"The aviation industry is increasingly relying on cockpit automation in its day-to-day operations," TSB investigator Daryl Collins said in a statement.
"Despite the many benefits of cockpit automation in aviation, it is vital that flight crews maintain their hands-on visual and instrument flying proficiency so that they have the experience and confidence to deal with unusual situations."
After halting the rapid descent, the crew was able to regain control of the aircraft. The flight continued to St. John's without incident.
There were no injuries or damage to the aircraft.
Since the incident, the investigation said, Cougar Helicopters has improved its training and now requires pilots to fly a minimum of two manually flown instrument approaches every 90 days.
The TSB said Cougar has also clarified its standard operating procedures involving what's called "unusual attitude recovery," as well as the use of autopilot.
Captain fired, despite non-punitive policy
The report revealed that the captain, who was in charge of the aircraft, lost his job, and also suggests that his colleagues were not happy with how it happened, as the company has told its employees they can report incidents without fear of punishment.
"The decision was made to terminate the captain’s employment based on the company’s determination that the captain could not operate safely in the offshore IFR [instrument flight rules] environment," the report found.
"To some employees, this appeared to be in conflict with the principles and processes outlined in Cougar Helicopters’ [safety management system] and with non-punitive reporting."
The board said both of the pilots had reported the incident and co-operated with the company’s investigation. It said Cougar maintains a non-punitive system for such reports, as well as what is known in the industry as a "just culture."
The investigation noted staff could be afraid to report future incidents if they fear losing their jobs.
An earlier version of this report said the Cougar helicopter dropped 153 metres (503 feet) in five seconds; in fact, it made the drop in 32 seconds.Sep 12, 2013 3:05 AM NT