HML-167 Command Chronology AUG 1970:


19 July 1970 Loss of aircraft TV-21, BuNo 154773. Fire in flight. Alpha damage. (Accident 271 Alpha)

DODD, Richard W. 1stLt Pilot Alpha Injury
CASNER, Lewis 1stLt Co-Pilot Alpha Injury
RODGERS, John M. Cpl Crew Chief Alpha Injury
BARNETT, John F. LCpl Gunner Alpha Injury
Submitted by Ken Davis, Researcher, The Virtual Wall

HML-167 AAR 19 JUL 1970:
MSN# 71 [APD (Sniffer)]

In Support of: 1stMarDiv
Flt Time: 2.9
FLt Code 1V3

No. of a/c: 1
Sorties: 3
Tasks: 1
Passengers Carried: None
Medevacs: None
Sightings: None
Recv'd Fire: No
Ord Exp: No
Delays: Yes [downed aircraft]
Operational Discrepancy: no

AC#: TV-5

Pilot: BOYER, Lynn
Copilot: ROLSTAD
Operator: TONEMAH


ATD: 12:45 ATR: 16:25

Marble Mountain ---> Coords:ZC2189 ---> Coords:ZC0780 ---> Marble Mountain

Relayed for approximately 40 minutes at end of mission orbiting passengers of downed gun bird.
Submitted by Alan H Barbour, Historian, Historian, USMC Combat Helicopter Association

HML-167 After Action Report - 19 JUL 1970:
MSN#: 74 [gunship support for APD sniffer mission]
Flt Time: 2.3
Flt Code: 1T4
No. A/C: 2

In Support of: 1stMARDIV
6 sorties
2 tasks

No passengers carried
No recon support
No MEDEVACS carried
No sightings
No received fire
No ordnance expended
No operational discrepancy

A/C# TV-36 (Section Leader)
Pilot GEASKIN
CoPilot DUEMLING
Crew Chief WIPEL?
Gunner ADAM

A/C# TV-21
Pilot DODD
CoPilot CASNER
Crew Chief RODGERS
Gunner BARNETT


ATD: 14:20
ATR: 16:40

MMAF --> UL Coords:ZC210890 LR AT 8386 --> UL Coords:ZC070800 LR Coords:ZC070760 --> MMAF

Mission Incomplete

Significant Delays: A/C 21 crashed NW of razorback [Charlie Ridge (Coords:AT8964) was located approximately 20 miles SW of DaNang at about 2600 ft elevation].
Submitted by Alan H Barbour, Historian, Historian, USMC Combat Helicopter Association

Personal Recollection:
I remember that day very well. The mission was the APD (people sniffer). Casner and Dodd were flying one of the two gunships flying cover for the APD aircraft. There was no enemy contact, and there was a lot of debate in the ready room after about fire/no fire, but it was pretty much agreed that it was some kind of mechanical problem. Duemling was KIA the following month. Geaslin, Boyer, and Rolstad are still around.
Submitted by Allyn Hinton, Squadron Pilot, HML-167

APD - PEOPLE SNIFFER - Wikipedia:
APD - Airborne Personnel Detector

A chopper was fitted out with two very large air scoops that were attached to the sides and skids of the ship. The scoops led to a special console that was positioned just behind the radio console. The console had a visor over it so that an operator could stick his head in there and read what was being detected.

The human body gives off ammonia via the wrists and ankles. The more you sweat the more ammonia is given off and the machine could read the ammonia in parts per million. That is the reason mosquitoes seemed to bother some people more than others; it was the ammonia that they were attracted to. The pilot had to fly low and slow for accurate readings. That was dangerous. The sniffer chopper was only used when the enemy was suspected of gathering in a given area. The APD required a flight at tree top level at a very slow speed which invited pot shots; usually 2 gunships flew escort. The guns couldn't really fly effectively at that speed because of their weight.


From Wikipedia regarding the People Sniffer

Detection method
The detection method used by people sniffers depended on effluents unique to human beings;[1] such as those found in urine and sweat.[2] The technology was developed by General Electric for the Army's Chemical Corps. Sweat, being partially composed of ammonia, when combined with hydrochloric acid produces ammonium chloride. Chemical officers planned the detection missions, later known as Operation Snoopy, while individual Chemical Corps soldiers learned how to use the detector equipment and conduct detection operations.

XM-2
The XM-2 personnel detector manpack, also known as the E63 manpack personnel detector,[3] was the first version of the people sniffer employed by the Army. The XM-2 featured a backpack mounted sensor with an air intake tube on the end of a rifle. The XM-2 was problematic in that it would often detect the soldier carrying it rather than the enemy. The device also made a distinct sound, easily detectable by the enemy.

XM-3
The XM-3 airborne personnel detector was a helicopter mounted personnel detector and the second version of the people sniffers. The XM-3 used two independent and identical units that operated in two separate modes. In 1970, the XM-3 became the M3 personnel detector; the M3 became standard issue and was employed almost daily in LOH-6, OH-58 and UH-1 helicopters.

Effectiveness
While useful, the detectors had to be used with some caution. People sniffers were known to be oversensitive and would often detect civilians or animals excreting bodily waste. In 1967 the Army Scientific Advisory Panel sent John D. Baldeschwieler to Vietnam in order to conduct controlled experiments and determine the ability of the people sniffers to detect ammonia. The tests showed that the people sniffer responded randomly to ammonia indicators, making it a very subjective instrument. Despite this, the ability of the people sniffer to detect other effluents, such as smoke, helped it to remain a valuable tool during the Vietnam War.
The Viet Cong (VC) and the North Vietnamese Army (NVA) were able to develop effective, low-tech countermeasures to the people sniffers. The airborne sniffers soon became recognizable to the VC and NVA and they would attempt to avoid detection by not firing on Operation Snoopy missions. Another effective decoy used by the NVA and VC involved hanging buckets of mud with urine in trees and then moving into another area.[1][5] Tactics such as these essentially rendered people sniffers ineffective in jungle terrain, but they remained useful in open areas, such as those found in the Mekong Delta.

Submitted by Alan H Barbour, Historian, Historian, USMC Combat Helicopter Association