A pilot drowsy after a mid-flight nap sent a plane plunging over the mid-Atlantic after mistakenly fearing a mid-air collision, injuring 16 passengers, an investigation found.
The Air Canada pilot was apparently suffering from "sleep inertia" - the stupor that follows a long nap - when he sent the plane plunging some 400 feet in 46 seconds, throwing those not wearing safety belts out of their seats.
The co-pilot quickly recovered, and the plane completed its route from Toronto to Zurich, where seven passengers were sent to hospital for further treatment. Fourteen passengers and two flight attendants were injured.
"Under the effects of sleep inertia, the (first officer) was likely confused and disoriented and perceived the aircraft on an imminent collision course," according to a report by the Transportation Safety Board of Canada.
The seatbelt sign was on, but several passengers were lying across seats in the economy section of the cabin, where all the injuries took place, said the report, based on an investigation of the 14 January 2011 incident.
It said the pilots had apparently not followed regulations requiring that "controlled rest" - which is encouraged on long flights - not exceed 40 minutes and be followed by 15 minutes of recovery time in which the pilot is awake but not operating flight controls.