Upon activation, it became the first and only separate airborne brigade in the United States Army. This was the beginning of a long series of “Firsts” for the Brigade.
On 5 May 1965, it became the first US Army ground combat unit committed to the war in South Vietnam, where further organizational changes were to take place. Australians attached to the Brigade were: 1st Battalion, of the Royal Australian Regiment (I RAR) and support troops of the 4/19th Prince of Wales Light Horse Regiment (1Troop), 105 Field Battery Royal Australian Artillery, 161 Field Battery Royal New Zealand Artillery, 3 Field Troop Royal Australian Engineers, 161 Reconnaissance Flight, Royal Australian Army Air Corps, 1st Australian Logistical Support Company.
The Brigade’s two infantry battalions, the First Battalion of the 503′ Infantry (1/503`d) and the Second Battalion, of the 503`d Infantry (2/503`) and the attached Australians of 1 RAR constituted the infantrymen available to the Brigade. Their mission was to protect the Bien Hoa Air Base and to close with and destroy or capture the enemy.
This was in fact the first operational ground force formed under the ANZUS Defence Treaty. ANZUS was a mutual defence treaty signed in 1951 between Australia, New Zealand and the United States of America. In 1965 the spirit of this treaty appeared as 173d Airborne Brigade (Sep) a tri-national brigade. The only such tri-national fighting force formed during the Vietnam War.
Vietnam Operations
1. Opord 5- 17-65 7 May – 9 July 1965 Bien Hoa Area
Initially, the 173rd was assigned to defend the Bien Hoa Air Base. The brigade routinely conducted sweeps up to 15 kilometers around the base, with company size operations often being the norm.
2. Frag Order 1- 11-65 7 June 1965- 2 August 1965 Bien Hoa Area
On 27 June, the brigade participated in the first joint U.S.-ARVN operation of the war. Nine battalions were involved in this mission which penetrated deep into the Western part of the Tan Uyen area of War Zone “D”. Over 400 VC casualties resulted from this combined operation. This was the first major engagement between the VC and the 173rd. The brigade destroyed a hard-core VC battalion.
3. PLEIKU 10 August 1965 – 5 September 1965 Pleiku- Kontum
The brigade loaded its men on C-130s and C-123s to relieve the siege of the Special Forces CIDG Camp at Du Co, about four kilometers from Cambodia. The 173rd provided security in the Thanh Binh Pass by conducting many platoon and company size sweeps of the area. Early September, the 1/503rd were ordered to Kontum. During this operation VC activity decreased to an 18 month low.
4. BIG RED 7 September 1965- 8 October 1965 Ben Cat, Puoc Ving, Di An, Phu Loc
Following a airmobile assault, the 1/503rd destroyed two VC hospitals, a signal school, and several training camps. As a result of the combat operations, 17 village chiefs, some of whom had not been to their villages in over a year, returned. Elections and religious ceremonies were also held.
5. IRON TRIANGLE 8-14 October 1965 Ben Cat
A lightning strike by helicopters following the first B-52 air strike in support of ground troops resulted in 106 VC killed.
6. NEW HOPE 21-27 October 1965 Di An, Phu Loi
The 2/503rd and B/3/319th cleared the area in preparation for the establishment of the 1st Infantry Division in that area.
7. HUMP 5-9 November 1965 War Zone “D”
The 1/503rd encountered a large enemy force. Moving on line, the brigade found itself locked in a battle with a main line VC regiment. The VC left their trenches and charged into a furious barrage of fire from the brigade. They were mauled by the 173rd leaving 403 Killed on the battlefield.
8. NEW LIFE 21 November – 17 December 1965 La Nga River Valley
The 173rd moved three infantry battalions, four artillery batteries, the Calvary troop and the command section by air to Vo Dat. The brigade’s mission was to prevent the rice harvest in the area from falling into the hands of the VC. For the first time, the brigade used the Long Range Patrols (LRPs), these small patrols would usually be infiltrated by helicopter deep into the enemy rear where they would operate independently for weeks at a time.
9. SMASH 17-23 December 1965 Phuoc Tuy
Operating approximately 50 kilometers southeast of Bien Hoa on the Courtenay Rubber Plantation, the 1st and 2nd of the 503rd along with the 1st/RAR began saturation patrolling. On the morning of December 18th the recon platoon of the 2/503rd encountered a defended VC trench system supported by numerous machine guns. B Company smashed into the enemy from a different direction and overran the enemy position resulting in 62 VC killed.
10. MARAUDER 1-8 January 1966 Hua Nghia Province
The New year began with the 1/503rd and the 1/RAR being airlifted into adjacent positions along the Oriental River in the Plain of Reed area of the Mekong Delta. The next morning , the 2/503rd fought through a series of fortified enemy positions using air, artillery and tear gas to rout the VC. 326 VC suspects were rounded up along with large numbers killed in the actions decimating the VC 267th battalion.
11. CRIMP 8-14 January 1966 Binh Buong, West of Hobo Woods
The Australians made contact first, and after heavy fighting, the RAR and the 173rd unmasked an extensive set of underground tunnels, captured several 12.7mm antiaircraft guns, killing over 128 VC and capturing another 91 while detaining 509 suspects.
12. ON GUARD 17-21 January 1966 Di An, Phu Loi
13. PHOENIX 26 February – 22 March 1966 Binh Duong & Bien Hoa Province
14. SILVER CITY 9-22 March 1966 Long Khanh Province
The 173D Airborne Brigade (SEP), including elements of the 1st Royal Australian Regiment, conducted a hellebore assault near the Song Be River in War Zone “D” to initiate Operation Silver City. The first few days of the operations consisted of thorough screening of the area, leading to the discovery of vast quantities of food, munitions, bunkers, tunnel systems documents, and several large VC base camps.
The seventh day of Operation Silver City will long be remembered by the troopers of the 173D, for on this day the 2/503rd Infantry Task Force was attacked from all directions by the 501st VC Battalion. The troopers held their perimeter while inflicting heavy losses on the guerrillas. Resupply of needy ammunition was effected during the battle by helicopter at no small risk to equipment and crews. Numerous tactical air strikes were initiated with great effectiveness. The VC had to resort to chaining their machine gunners to the tripods of their weapons, but even these measures could not stop the crack troopers of the 173D.
The 1st Battalion, 503d Infantry was directed to reinforce the 2nd Battalion during the battle. The VC element was nearly annihilated by this time and chose to break contact rather than tackle two battalions of SKY SOLDIERS. Four hours after initial contact, all VC were routed or destroyed.
The after-action mop-up patrols counted a total of 302 VC bodies with only seven US losses, the highest kill ratio to date. Throughout the rest of the operation it was indicated that an estimated 150 additional VC dead had been dragged away.
15. DENVER 10-25 April 1966 Song Be, Phuoc Long Province
The brigade task force discovered over 34 tons of rice and 2,167 documents during patrols and Eagle flights with no major elements of VC encountered.
16. DEXTER 4-6 May 1966 Tan Uyen
The brigade initiated the three day operation in the northwest portion of Bien Hoa province.
17. HARDIHOOD 16 May- 8 June 1966 Phuoc Tuy Province
On 19 May the 1/503d Infantry became engaged with an estimated fifty VC. The firefight that ensued resulted in twenty VC killed with minimal friendly casualties.
Source – The History of the 173rd Airborne