**EDIT: Never mind, re-read the text and now understand the execution countermeasure is monitoring and cross checking instruments.**
Can anyone help me understand the answer to this question in the CHUF book:
"The pilot of a piston engine aircraft notices that the oil temperature is very high and the oil pressure is beginning to drop. She decides to abandon the original flight plan and lands at the nearest aerodrome with maintenance facilities. In this case the external threat has been mitigated by implementing
(a) an execution countermeasure followed by a review countermeasure
(b) a latent threat and a review countermeasure
(c) a planning countermeasure followed by an execution countermeasure
(d) a review countermeasure followed by an execution countermeasure"
I picked (d) because I thought she reviewed the oil Ts & Ps, then executed a landing, but the correct answer was (a)
The abnormal instrument indications were observed by frequent monitoring of the instruments. That's a review countermeasure. Based on that observation, the pilot took action and amended the original flight plan. That's an execution countermeasure. That makes the answer (d).
I think I might have confused everyone. The original answer was correct and I was wrong. I realised after re-reading that I had it around the wrong way. Cross checking is execution and the landing is the review.