When must crew members be secured by safety belts and harnesses according to ICAO Annex 6, Part I, Chapter 4, 4.8.1?

Here are the solutions to the questions:

1. The question asks for the correct statements regarding when crew members must be secured by safety belts and harnesses. According to ICAO Annex 6, Part I, Chapter 4, 4.8.1, crew members must be properly secured during take-off, landing, and whenever the commander deems it necessary in the interest of safety.
   • Statement 2: "during take off" - Correct.
   • Statement 3: "during landing" - Correct.
   • Statement 4: "whenever deemed necessary by the commander in the interest of safety" - Correct.
   • Statements 1 ("during taxiing") and 5 ("during other phases