05Aug67-'People Sniffer' Flushes Enemy
Copyright 1967 "Stars and Stripes"
Contributed by Crusader Mike Rasbury

        LONG THANH, (9th INF-IO) - Rifle fire crackled from beneath the thick canopy of tangled mangrove limbs which obscures much of the treacherous Rung Sat Special Zone from aerial observation.
 One of the rounds ripped into the tail of the Army UH-1D helicopter hovering 50 feet over the slimy ground.
With the crack of rifle fire, a reconnaissance mission became combat.
        Machineguns on the chopper answered the enemy rounds with a stream of deadly fire. Tracer bullets burned into the twisted foliage
     concealing the enemy sniper. Minutes later, after several low-level firing passes, it was over.
        An enemy, his rifle silenced, sprawled face down in the stinking mud.
 
The 9th Infantry Division helicopter, one of a pair assigned to sweep a portion of the Rung Sat northwest of Vung Tau,
had been out searching for the enemy who lays in wait for ships bound for Saigon from the South China Sea.

But this time, it has been recon with a new twist.
The chopper, from Troop D of the division's 3rd Squadron, 5th
     Armored Cavalry, carried a device which can "smell" enemy soldiers concealed below.
        One of the Army's newest detection devices, the chemical personnel  detector or "people sniffer," mounted on a helicopter, samples the air and tells its operator when it "smells" humans.
Moments before the engagement, SFC Charles W. Bracey, a member of the division's chemical section and a "people sniffer" operator,
 had announced, "I've got a maximum reading."
        First Lieutenant Michael Terry, the pilot, eased the chopper into another treetop level sweep of the area which had produced the "max" reading.Meanwhile, reports of the find had been radioed to another helicopter circling high above. 
Inside it, 1st Lt. Robert A Guerra, a  member of the division's aerial intelligence section, was plotting the exact location of the find.
Both choppers swung down for a closer inspection of the area. 
As they hovered over the thatch of mangrove branches and stunted vegetation, the enemy sniper had opened fire, turning recon into combat.

        The chemical personnel detector, operated by Bracey, had been sampling the humid air at treetop level for more than an hour
when its indicator needle jumped and its intense beeping announced humans  presence down there.

        "People sniffers" have been scanning Vietnam's jungles and swamps with the 9th since late in May and we've found something just about every time we have taken them out." Bracey said.
        The device weighs about 25 pounds and is no larger than an  overnight bag. Taking  a continuing sample of air, the sniffer
     humidifies it and examines the sample for several substances which  humans give off when they perspire.
        The detector can pick out the hint of smoke from a tiny camp fire because of its carbon sensing capability.
Because it detects smells rather than sights, it is especially useful for night reconnaissance.
It has become much more effective on helicopters than on a man's back.
        Since it would also detect friendly troops and civilians, it is used primarily where neither villages nor friendly forces are.
        It detects only human odors, thereby eliminating the danger of  false alarms.
 It was developed at the Army's Limited War Laboratory at Aberdeen Proving Grounds in 1963.

1967 Time Line
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