In an aircraft reciprocating engine best economy will occur... Question 15 options: 1) at a mixture ratio leaner than best power 2) with the same mixture ratio as best power 3) at a mixture ratio richer than best power In an aircraft reciprocating engine best economy will occur... Question 15 options: 1) at a mixture ratio leaner than best power 2) with the same mixture ratio as best power 3) at a mixture ratio richer than best power