An Air Canada pilot mistook the planet Venus for another aircraft and plunged his plane towards the Atlantic Ocean to avoid a collision.
A report released Monday by the Transportation Safety Board of Canada found 16 people were injured after the Boeing 767 dropped 400 feet to avoid an imaginary crash with an oncoming US C-17 military cargo plane.
The report blamed pilot fatigue and breached rules over mid-flight napping for the January 2011 incident on a Toronto to Zurich flight.
An investigation by the safety board -- based in Gatineau, Quebec -- revealed the first officer had just woken from a "controlled rest" when the captain informed him a US cargo plane was flying towards them.
He "initially mistook the planet Venus for an aircraft," then thought an oncoming plane was descending from above and risked an "imminent collision."
The cargo plane was actually 1,000 feet below the Air Canada flight.
The report said, "Under the effects of significant sleep inertia (when awareness and performance are degraded after sleep), the first officer perceived the oncoming aircraft as being on a collision course and began a descent to avoid it."
Fourteen passengers and two crew members were injured during the incident. The passengers were all in economy class, and none were wearing seatbelts.
Air Canada spokesman Peter Fitzpatrick said, "We sincerely regret that some of our customers were injured, and we have taken measures to prevent a reoccurrence of this type of event."
Under Canadian regulations, pilots are permitted to take "controlled rest" naps of a maximum of 40 minutes during flights.