Question: what distance / altitude to be considered to order your flight to attack a vehicle column?

[kraut1]

In general I have no problems to use the radio order F2, F1, F3 to advise my flight to attack ground targets.

I used that in the last weeks frequently to attack artillery and ships.

But yesterday I flew 2 times a vehicle (trucks) column attack, but my flight did not react.

Today I tested 2 small test missions, worked, no issue.

I have checked the status of the trucks, they are enemies and engageble.

Are there any recommandations existing, in which distance / altitude to the trucks the radio command shall be send?

Many thanks in advance!