I am going to show you how my mind works when it comes to loglines. I will go step by step.

(A group of friends on a weekend trip to Las Vegas find themselves caught up in a long-standing feud between Native Americans and gangsters after their helicopter is shot down in the Arizona desert during a tour of the Grand Canyon)

1: You can drop the part about being on a weekend trip to Las Vegas. It doesn’t add any important information to your logline and just uses word space, let me take it out and show you.

(A group of friends find themselves caught up in a long-standing feud between Native Americans and gangsters after their helicopter is shot down in the Arizona desert during a tour of the Grand Canyon)

2: You can drop the part about Arizona because you also mention the Grand Canyon, so you have established where they are

(A group of friends find themselves caught up in a long-standing feud between Native Americans and gangsters after their helicopter is shot down during a tour of the Grand Canyon)

3: You should write the logline in chronological order, so I would start with the helicopter being shot down.

( After their helicopter is shot down during a tour of the Grand Canyon, a group of friends find themselves caught up in a long-standing feud between Native Americans and gangsters )

Now we have a concise logline: There are still two changes that need to be made but I don’t know enough about your story to make them.

A: Instead of saying a group of friends you should tell us a little about the lead character

B: You should tell us whether the leads goal is to escape back to civilization or to help one side defeat the other.

(After her helicopter is shot down during a tour of the Grand Canyon, a cheerleader instructor and her friends help a friendly tribe of Native Americans fight off vicious gangsters determined to shut down the native’s independent casino)

But of course, your logline would probably be different because I just put in cheerleader instructor as a result of having no clue as to who your lead character is, so I just took a wild guess, I’m sure your lead is something else entirely.