Whilst on routine patrol, 155490 was shot down near Ap Bac, 45 miles west of Saigon. Per operational diary for US Navy Squadron VAL-4: "BuNo 155490 was shot down by enemy ground fire Saturday night, July 12. Both pilots are classified as missing in action but there is little reason for hope. The airplane was observed to be receiving fire at 2700 feet altitude, enter a shallow dive and strike the top of a mountain 1700 feet high. Explosion and fire ensued. No ejection seat rocket flame or inflated parachutes were in evidence. Air cover remained over the area all night and the next day, monitoring emergency radio frequencies, but received no signals.
 
A survey of the crash site from the air the next day revealed that the aircraft had broken up upon initial contact with the top of the mountain and spewed parts over a wide area for several hundred yards down the mountainside. Since the mountains and valley below are occupied by enemy forces and there is no suitable terrain to land a helicopter in the area, there is no intention at this time for further investigation at the crash site.
 
Since there was no radio transmission from the aircraft and that it appeared to be out of control after being hit by the ground fire, it is concluded that both pilots probably received fatal or incapacitating injuries prior to the crash"
 
Both crewmembers - Lt Aubrey Grady Martin (pilot) and Lt(jg) Roy Dean Sikkink (observer) - posted as MIA/KIA. The body of Lt(jg) Sikkink was recovered in 1969. The body of Lt. Martin was later found, and repatriated to the US on 31 July 1974, but not formally identified until 14 June 1977
 

Lost during patrol along the the Saigon Long Tau shipping channel while investigating suspicious sampan.
 
Per VAL-4 operational diary: "BuNo 155503 from the Vung Tau Detachment was lost on Saturday evening, 20 December 1969. The single aircraft was patrolling the Saigon Long Tau shipping channels with a pilot and Marine air observer aboard, under control of the Moon River Naval Operations Center.
 
The pilot advised the Center that he was descending to investigate a suspicious sampan at about 4:45 p.m., and the Center was unable to contact the flight after that radio transmission. After twenty minutes of silence, the Vung Tau VAL-4 alert crew was scrambled to search for the missing aircraft. The burning wreckage site was spotted 10 minutes later in the swampy Rung Sat Special Zone, 8 miles north of Vung Tau. There were no parachute canopies visible in the area and no beeping or voice transmissions were detected on the survival radio frequencies.
 
At the present time there is no factual evidence to indicate the cause of the crash, but the area is definitely hostile where ground fire is often encountered. ARVN troops are being inserted in the area to set up a perimeter around the crash site and a Navy investigating and salvage team will be placed on the scene by helos on Sunday morning."
 
Both crew - Lt(jg) Joel Alexis Sandberg, USN, and Capt Carl Edwin Long, USMC - posted as MIA/KIA. The remains of Capt Carl Edwin Long were recovered and returned to the United States in 1992. Carl's remains were buried at Arlington National Cemetery (Site 50 of Section 68) In Washington D.C., on September 16, 2004.
 

Crashed after being hit by ground fire during attack. Both the Pilot Lt Cdr John P Westerman and the co-pilot Lt(jg) Peter W Ford ejected, and survived the ejection to be rescued by an army helicopter.