The Air Canada Boeing 767–333 was flying on 13 January 2011 from Toronto, Ontario, to Zurich, Switzerland. Approximately halfway across the Atlantic, during the hours of darkness, the aircraft experienced a 46–second pitch excursion. This resulted in an altitude deviation of minus 400 feet to plus 400 feet from the assigned altitude of 35 000 feet above sea level. Fourteen passengers and 2 flight attendants were injured.
The Transportation Safety Board of Canada (TSB) investigated this occurrence and authorized the release of this report on 29 February 2012. However, I found out about it only today while listening to the radio so initially I thought it had been just released.
From the report (tip: mouse over the acronyms to see what they mean) :
The FO initially mistook the planet Venus for an aircraft but the captain advised again that the target was at the 12 o’clock position and 1000 feet below. The captain of ACA878 and the oncoming aircraft crew flashed their landing lights. The FO continued to scan visually for the aircraft. When the FO saw the oncoming aircraft, the FO interpreted its position as being above and descending towards them. The FO reacted to the perceived imminent collision by pushing forward on the control column. The captain, who was monitoring TCAS target on the ND, observed the control column moving forward and the altimeter beginning to show a decrease in altitude. The captain immediately disconnected the autopilot and pulled back on the control column to regain altitude.
Findings as to causes and contributing factors
- The interrupted sleep obtained by the first officer prior to the flight increased the likelihood that rest would be needed during the overnight eastbound flight.
- The first officer slept for approximately 75 minutes which likely placed the first officer into slow–wave sleep and induced longer and more severe sleep inertia.
- The first officer was experiencing a circadian low due to the time of day and fatigue due to interrupted sleep which increased the propensity for sleep and subsequently worsened the sleep inertia.
- By identifying the oncoming aircraft, the captain engaged the first officer (FO) before the effects of sleep inertia had worn off.
- Under the effects of sleep inertia, the first officer perceived the oncoming aircraft to be on a collision course and pushed forward on the control column.
- The frequency of training and depth of the training material on fatigue risk management to which the flight crew were exposed were such that the risks associated with fatigue were not adequately understood and procedures for conducting controlled rest were not followed by the flight crew.
- Although the seatbelt sign was on and an announcement about potential turbulence was made, several passengers were injured during the event because they were not wearing their seatbelt.
Findings as to risk
- North American–based pilots flying eastbound at night towards Europe are at increased risk of fatigue–related performance decrements.
- The use of multiple safety occurrence reporting systems may result in some safety issues not being properly identified and analyzed.
- Some passengers may not be aware of the inherent risks in not wearing a seatbelt at all times when seated.
- As the aircraft cockpit voice recorder (CVR) was only capable of recording for 2 hours, the event was overwritten.
Th full report is here.
Also, I read that the Air Canada Pilots Association president Paul Strachan said: “The current regulations are not sensitive at all to the time of day … (North Atlantic flights) are certainly fatiguing in comparison to most other flying.” He reportedly said Air Canada operated trans-Atlantic flights with two pilots whereas U.S. carriers used three to share the load. I didn’t know about that.