Name: Mark John Robertson   
Rank/Branch: Warrant Officer/US Army 
Unit: Troop B, 2nd Squadron, 
17th Cavalry, 
101st Airborne Division (Airmobile)             

Date of Birth: 18 August 1949
Home of Record: Detroit, MI
Date of Loss: 10 February 1971 
Country of Loss: South Vietnam
Loss Coordinates: 162025N 1070647E (YD257076) 
Click coordinates to view (4) maps

Status in 1973: Killed/Body Not Recovered 
Category: 2
Aircraft/Vehicle/Ground: OH6A "Cayuse"
Other Personnel In Incident: Joseph R. Pietrzak (missing) 


SYNOPSIS:  The Hughes OH6A Cayuse was known by the troops by its nickname "Loach" - a derivative of "light observation helicopter." The armed OH6A was the primary scout helicopter used in Vietnam and usually carried a crew of two. The pilot controlled a mini-gun and a gunner/crew chief handled a "free 60" machine gun, among other weapons, which was attached to the aircraft by a strap. The Loach crews flew the most dangerous missions assigned to Army aviators because they flew low and usually slow enough to get a good look at the ground making them easy targets for the enemy.

On 10 February 1972, WO Mark J. Robertson, pilot; and Sgt. Joseph R. Pietrzak, observer; comprised the crew of an OH6A helicopter (tail #17765) conducting an aerial visual reconnaissance mission in the vicinity of Tiger Mountain, Thua Thien Province, South Vietnam. Their mission was to locate, report on and attack any NVA troops infiltrating into South Vietnam from Laos. Their area of operation included extremely rugged jungle covered mountains between the South Vietnamese/Lao border and the northern most portion of the infamous A Shau Valley.

This area also included a primary gateway from the equally notorious Ho Chi Minh Trail into strategic sections of northern South Vietnam. When North Vietnam began to increase its military strength in South Vietnam, NVA and Viet Cong troops again intruded on neutral Laos for sanctuary, as the Viet Minh had done during the war with the French some years before. This border road was used by the Communists to transport weapons, supplies and troops from North Vietnam into South Vietnam, and was frequently no more than a path cut through the jungle covered mountains. US forces used all assets available to them to stop this flow of men and supplies from moving south into the war zone.

Adjacent to their mission area just over the border in Laos was Oscar Eight; a sector of eastern Laos also located in rugged jungle covered mountains. Burrowed deep in the hills of Oscar Eight was North Vietnamese General Vo Bam's 559th Transportation Group's forward headquarters. It was also the Ho Chi Minh Trail's control center as well as containing the largest NVA storage facility outside of North Vietnam.

WO Robertson and Sgt. Pietrzak flew low over the primary road that crossed over from Laos into South Vietnam, which then turned toward the south and ran along the east side of the A Shau Valley. They spotted NVA forces moving along it. After reporting their position, WO Robertson initiated an attack pass. As he did so, the helicopter was struck in the pilot's compartment and fuel section by heavy .51 caliber machine gun fire. The Loach was seen to burst into flames, fall vertically, and explode on impact on the south side of the road. American units operating nearby reported the OH6A continued to burn for four hours. Attempts were made to rescue the downed aircrew. However, other helicopters in the area were unable to land and search for survivors because of the heavy enemy presence and rapidly deteriorating weather conditions.

The location of loss was within a mile of the primary road, approximately 3 miles north of the South Vietnamese/Lao border and 4 miles northwest of the north end of the A Shau Valley. It was also 28 miles southeast of Khe Sanh and the same distance west-southwest of the city of Hue.

None of the aircrews conducting the visual search for Mark Robertson and Joseph Pietrzak saw survivors or bodies in or around the blazing helicopter. Radio frequencies were monitored after the crash, but no beepers were heard. Because of the heavy enemy activity in the area, no ground search was possible. Based on the circumstances of loss and eyewitness reports, it was determined that Warrant Officer Robertson and Sergeant Pietrzak died when their aircraft crashed to the rugged jungle floor. Both men were immediately listed Killed in Action/Body Not Recovered.

In 1992, a National Security Agency (NSA) correlation study of all communist radio intercepts pertaining to missing Americans, which was presented to the Senate Select Committee on POW/MIA Affairs in a classified format, was finally declassified and made public. According to this document, 4 North Vietnamese radio messages were intercepted and correlated to this incident. The NSA synopsis states: "at Binh Tram 41 (a way station used by the communists for a variety of purposes) --- 12.7mm weapons crew shot down three aircraft. Two helicopters were shot down at Ban Dong. The first was shot down by a machine gun and an American pilot was killed …... The 12th day of the crash program, Company 4 of the 71st Engineer Battalion hit a helicopter with an infantry weapon."

While the fate of Mark Robertson and Joseph Pietrzak is not in doubt, each man has the right to have his remains returned to their family, friends and country if at all possible. For other Americans who remain unaccounted for in Southeast Asia, their fate could be quite different.

Since the end of the Vietnam War well over 21,000 reports of American prisoners, missing and otherwise unaccounted for have been received by our government. Many of these reports document LIVE American Prisoners of War remaining captive throughout Southeast Asia TODAY.

Pilots and aircrews in Vietnam were called upon to fly and fight in many dangerous circumstances, and they were prepared to be wounded, killed or captured. It probably never occurred to them that they could be abandoned by the country they so proudly served.