On 13 February in order to secure FSB 31 it was planned to land the 6th Airborne Battalion on a mountain range northwest of the base to control a valley running southeast to FSB 31. Despite preparatory B-52 strikes the first helicopters transporting the 6th Airborne were met by heavy fire and the remaining helicopters were diverted to alternate sites. The 6th Airborne continued to receive fire and eventually withdrew to FSB 31 having lost 28 killed and 23 missing. That afternoon the 39th Ranger Battalion engaged a PAVN force 3km west-southwest of Ranger North killing 43 PAVN for the loss one killed and capturing two 37mm anti-aircraft guns and two 12.7mm machine guns and large quantities of ammunition. The 3/1 Battalion found a supply cache containing 30 75mm recoilless rifles and 50 55 gallon drums of gasoline. Meanwhile the 2/3 Battalion operating 6km north-northeast of LZ found three trucks. That afternoon the 1/1 Battalion engaged a PAVN unit 3km south-southwest of LZ Don killing 28 and capturing a storage area containing seven RPDs and large quantities of food.