1.

Lieutenant Hamilton shot down the airship in 1916.

WHICH TENSE?

WHY? Because the action happened ...

... in the PAST and THERE IS a definite time reference ('in 1916')

2.

The bravery of a flying ace has raised £90,000 for sick children.

WHICH TENSE?

WHY? Because the action happened ...

... in the RECENT PAST and THERE IS NO time reference

3.

He came quietly when he was stopped and asked for his papers.

WHICH TENSE?

WHY? Because the action happened ...

... in the PAST and THERE IS a definite time reference ('when he was stopped and asked for his papers')