Covering the other sideline

A major disadvantage in working with a 3-man crew is that there is no Line Judge (LJ) to cover the other sideline. Instead, the Umpire must cover downfield receivers to the side away from the Linesman (L), and he may be in poor position to judge whether a receiver on the sideline was inbounds or had possession when going out of bounds.

Now, with a 4-man crew, LJ covers downfield receivers so the Umpire can get back to watching the line blocking and stepping up to the line on passes to check for ineligibles downfield. All those downfield passes that end up near the sideline — a guessing game with a 3-man crew — now get a close look from LJ as to whether the receiver had possession and came down inbounds.

Now let's look at this example:

Continued...