What are the record-keeping requirements for flight or operational use of an aircraft only flown under Part 91? Rental aircraft always have such a logbook, for obvious reasons, but are privately-owned-and-operated aircraft required to keep such a log by regulation?
AC 43-9C further clarifies the above.
61.51 dictates pilot experience logging requirements. Some of the information recorded in a pilot log is duplicated in the aircraft flight log.
In Canada, this is referred to as a "journey log" and the requirements are explicitly stated in 605.94
AC 91-70B concerns flying in "oceanic and remote continental airspace", but deep in 126.96.36.199 recommends a journey log and references ICAO Annex 6.
ICAO Annex 6 Part I 11.4 defines the "journey log" for commercial flights, and is a "recommendation".
ICAO Annex 6 Part II 2.8.2 similarly defines the "journey log" for general aviation, and is also a "recommendation".