[tag:canada]

Taking control of an aircraft from a pilot in command without their consent would normally be an offence under [s. 7.3(1) and 7.41][1] of the *Aeronautics Act* (but I'm doubtful that the act of the passenger in your scenario is "endangering the safety" of the aircraft) and possibly [s. 76][2] of the *Criminal Code* (I'm also doubtful that the *mens rea* is met in the specific scenario you describe). Restraining the pilot would be at least plain assault (*Criminal Code*, [s. 265][3]).

Regardless, in your scenario, the act would most likely be justified by the [defence of necessity][4]. "[T]he situation must be so emergent and the peril must be so pressing that normal human instincts cry out for action and make a counsel of patience unreasonable." There must also be "no reasonable legal alternative" to avoid the imminent peril. See generally, *Perka v. The Queen*, [\[1984\] 2 S.C.R. 232][4]. Self-defence also seems to have straight-forward application here. 

Possible offences for the pilot: murder, attempted murder, manslaughter, criminal negligence causing bodily harm, criminal negligence causing death.


  [1]: https://laws-lois.justice.gc.ca/eng/acts/a-2/page-7.html#h-8320
  [2]: https://laws-lois.justice.gc.ca/eng/acts/C-46/section-76.html
  [3]: https://laws-lois.justice.gc.ca/eng/acts/c-46/section-265.html
  [4]: https://law.stackexchange.com/a/89684/46948