Infantry operations typically lasted 5 to 10 days. The fighting patrols had to be self-contained and carry all their ammunition and rations. Normal practice was to withdraw after a contact, but staying in the area often led to further ambushing opportunities. Ambushes were the most common tactic, often lasting several days. However, Indonesians did not usually move at night so ambushes could withdraw to a harbour position. Because aircraft were not allowed to fly across the border casualties had to be evacuated by foot until they were back across the border, except in the most extreme cases with personal authorisation by DOBOPS.