 When the SR patrol is in an area where the enemy knows there might be some patrol activity, helicopters may make a number of quick touchdowns, all but one simply to mislead the enemy.If it is reasonably certain that the enemy knows some patrols are present, but not where, the helicopters may even make some touchdowns more likely to be observed, but leave boobytrapped supplies.They may need to have wounded personnel replaced, and sometimes evacuated.