In this task, we ask you to write a question that asks about "event duration", based on a given sentence. The question will likely start with "How long". Your question should be answerable based on the common knowledge of how long certain events usually last. Don't create questions which have explicit mentions of answers in the text. Instead, it has to be implied from what is given. In other words, we want you to use "instinct" or "common sense". Note that the written questions are not required to have a single correct answer.

Let me give you an example: Sentence: Jack played basketball after school, after which he was very tired.
The answer to this example can be: How long did Jack play basketball?
Here is why: the question asks about the duration of an event; therefore it's correct question.

OK. solve this:
Sentence: The report of American 11 heading south was the first; Delta 1989 was the second.
Answer:
For how long did American 11 head south?