Learn Russian: Стоило экипажу достать шланг, как снова вспыхнул огонь. - As soon as the crew got the hose out, the fire flared up again.

This is a special grammatical structure: стоило + Dative + Infinitive + как + Past tense. It translates to 'no sooner had someone done something than' or 'as soon as'. It emphasizes that one completed action immediately triggered another sudden event.

Why is экипажу in the dative case?

In this structure, the logical subject (the person or thing performing the infinitive action) must take the dative case. Since the crew (экипаж) is the one getting the hose, it becomes the dative экипажу.

Could we use the imperfective verb доставать instead of the perfective достать?

Generally no. The стоило ... как construction relies on perfective verbs in both halves because it focuses on a strict sequence of events. The fire flared up not while they were in the process of getting the hose, but at the exact moment the action was completed (достать).

Does the second part of the sentence always have to start with как?

Yes. In this specific idiom, как is the mandatory linking word connecting the trigger to the result. Just like you must use 'than' with 'no sooner' in English, you must use как with стоило in this Russian structure. You cannot swap it for когда (when).

Why is at the very end of the sentence instead of before ?