I saw the following sentence in a book titled *[Awaken The Giant Within](https://books.google.co.uk/books?id=iPpyLpX0Y1sC&pg=PT20&dq=%22As%20I%20flew%20over%20the%20city,%22%20%22I%20suddenly%20recognized%22&hl=en&sa=X&ved=0ahUKEwjix9DZmLPcAhWqwFQKHSsSDeYQ6AEIKDAA#v=onepage&q=%22As%20I%20flew%20over%20the%20city%2C%22%20%22I%20suddenly%20recognized%22&f=false)* 

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> As I flew over the city of Glendale, I suddenly recognized a large building, and I stopped the helicopter and hovered above it"
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Why is the sentence not written in the past progressive tense? 

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> *As I **was flying** over the city,* I suddenly recognized a large building…
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