I.why [waɪ, am. angl. hwaɪ]PRISL.Why translates as pourquoi in French, but see II. and III. below for exceptions. As with other words such as où, quand, comment etc., questions are formed by inserting est-ce que after the question word: why did you go? = pourquoi est-ce que tu y es allé? or by inverting the subject and verb after the question word, which is slightly more formal: pourquoi y es-tu allé? In spoken French the question word can be put at the end: tu y es allé pourquoi? why occurs with certain reporting verbs such as ask, explain, know, think and wonder. For translations, see these entries.
The converted aircraft were purchased following the Falklands War, after a requirement for additional air-to-air refuelling operations had been identified.