Is it possible to switch engines during a F1 season?
Formula 1 teams are allowed to use a total of five engines this season. Is there a rule that an engine must be used in consecutive races? Can you use Engine A in two races, switch to engine B for three races and then return to engine A?
The regulations do not forbid this. In practise teams do this, because engines are being developed throughout the season. Development is only allowed for new engines. If you would use all five engines in the first five races, you could not do any development work on those - leaving you with a significant disadvantage.