TThe "People Sniffer"

     I was amazed at the many gadgets and such that we used over there.  Infrared photos told us where all the trails and tunnels were.  Side scanning radar let us know what was moving when.  And then there was the "people sniffer".  I didn't believe my ears at first, a chopper that could smell out Charlie, you got to be kidding.  It was real though and sure was a different kind of mission.
     Sure enough, here was a chopper 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
     As was explained to me, 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.  I was told that was the reason mosquitoes seemed to bother some people more than others, it was the ammonia that they were attracted to.  Only trouble was that you had to fly slow and low for supposedly accurate readings and that was a definite no-no for pilots interested in longevity.  The sniffer chopper was only used when Charlie was suspected of gathering in any given area for whatever reason.  It's use usually required you to fly at tree top level at a very low speed which invited pot shots so usually 2 gun ships flew escort.  Only trouble was that the guns couldn't really fly effectively that slow and we were passed by many a time which looked nice but meant we were not covered for seconds at a whack.  The operator had to bury his head in the console and would relay to us a "Mark" or "Hot" which we promptly relayed to the C&C ship above, which was conveniently out of bullet range.  It was the C&C ship's job to mark on the map where each reading was and whether it was just a "Mark" or a "Hot".  It was also C&C's job to tell us which direction to go in.  Behind the C&C was rescue 1 just in case we or a gun went down.
     Though the mission was an interesting one, pilot wise, we didn't like sticking out necks out like that. I did know pilots though that volunteered for that mission and even flew it without their chicken plate.  While the pilots were enjoying the scenery that was being forced on them the poor door gunner and crew chief were at 100% with machine guns at the ready and eyeballs straining at the max for that one guy that would jump out of the tree line and spray the ship with AK-47 fire.
     Now I have to admit the machinery was impressive.  The operator could not see where we were going or what we were going over.  On one occasion I turned the ship slightly and flew directly over a lone Vietnamese boy that was on the back of a water buffalo who was tending a herd of buffalo that were in an open field.  About 100 yds later the operator recorded a "Mark".  It worked.
     I flew the sniffer chopper several times and on one occasion we inadvertently found out just how sensitive that machine really was.  I had been flying the sniffer ship, with escort, somewhere south of the air base at Phan Rang and we had come up empty.  At the end of the day the other ships had to go do something else and I was told to bring the ship back to Phan Thiet.   South of Phan Rang was a huge grass area that we sometimes when to hunt rabbits.  It was miles and miles of flat grass that was only about 6"-8" high with an occasional gully here and there.  There were rabbits there and when we had to get rid of the old machine gun ammo we just used it up on the rabbits.  The gunners love it and it made things interesting for a while.  My best guess was 200 rounds per rabbit because they run back and forth like an NFL halfback.
     On this particular occasion we had to get back fast so rabbit hunting was out.  We did though get down on the deck where we could low leveling at full speed and enjoy one of the thrills of flight.  All of a sudden the operator yells out "Hot, Hot, Hot".  He had apparently left the machine on and it was giving a reading of "Hot" be it only for a few seconds.  We immediately pulled up and eyeballed the area.  There was nothing there, just grass and a small gully that maybe a little rabbit could hide in.
     With door gunners on the alert we got down to sniffer speed and altitude and went over the spot from a different angle.  We got a "Hot" reading again just over the gully.  We did it again and got the same "Hot" reading.  We didn't see anything so we marked the spot on the map that the operator had and let it go at that.  When we got back the operator turned in the findings to headquarters.
     A few days later we heard that the local troops went for a look see and found 9 VC hold up in a tunnel in the little gully that registered all the "Hot" readings.  Seems they were in there sweating away with the ammonia apparently going up the vent holes.  Glory be, the thing worked just as well at full speed as at recommended speed.
     It amazed me at all the little toys and gadgets we had over there and that was just the ones that I was privy to and remember I, as a warrant officer, was the lowest of the lows officer wise.   I sometimes wondered what was out there that was being used that I would never know about.  Somebody once answered, when asked why the war was taking so long,  "because there were so many toys to play with".   I sometimes wonder how many lives were sacrificed for those toys and how many more were indeed saved by those toys ?  I know it had to be done but it still hurts thinking of it that way.

     The End.

    30+ Years Later:

    These stories have now grown beyond just me and I don't mind that at all.  I am no hero by any means, I am but the messenger and these stories are here for you to enjoy and to learn from so you may better understand what was happening back then.  With that in mind pertinent people of that era sometime contact me with their similar stories.  If what they have to say fits into my stories and adds to them and I find them credible I don't mind at all to include what they have to say with that specific story.
    One such person is Jack Inman, a "people sniffer" operator who started "sniffing" up North in the Dak To area just as I was going into the 192nd.  Its people like Jack that did their "thing" with little notice and in doing so saved many lives.  I'm surprised he is still here to talk about it all, he sure beat the odds but then again, maybe it was meant to be that way all along.  Here is Jack's story.
 More on "The People Sniffer"

Accounts by Jack Inman

My name is Jack Inman.  I was referred to Galkie’s web page about the “people sniffer” and Galkie asked me to contribute a description of my experiences with similar technology.

I was a “people sniffer”, a.k.a. Airborne Personnel Detector.  My MOS (Military Operating Specialty?) in the US Army was 52E, Chemical Staff Specialist.  I was trained in Chemical, Biological and Radiological (CBR) warfare at Ft. McClellan, AL in early 1968 and shipped out to RVN in July, 1968 as a SP-4.  I was assigned to the 4th Infantry Division Chemical HQ.  General duties included tear gas, defoliate (e.g. Agent Orange), and flame weapon deployment, but soon after arrival I was enticed into volunteering to become an APD operator, which we called “Snoopy”.  Snoopy was a volunteer activity because of the inherent dangers involved, but I was intrigued by the technology and it also got me out of the more mundane duties that enlisted men were subject to such as KP and guard duty.

Yes, the people sniffer could “smell” people or human activity in general such as body effluents, smoke or other exhausts, and it was very effective.  I'm not familiar with the exact equipment that Galkie describes, but the technology certainly evolved with time and did so even during my tour.

The first ADP equipment I worked with was actually designed to be carried on a soldier's back in the jungle with a probe attached to his rifle.  I never operated it this way.  This tactic proved not to be very effective because air currents in the jungle are irregular.  It was in fact very possible to smell your own troops using this tactic.  It was also possible to walk right up to an enemy without detecting him due to uncooperative air currents.  Plus the fact that it was an otherwise useless piece of equipment that the soldier had to tote made it a passing fad on the ground.

However, the air circulated through the jungle, but also rose to above the treetops, which offered a much better sample space.  The tactics evolved to mounting the APD in a helicopter and flying just above the trees to collect and analyze the air samples.  This proved to be much more effective and also allowed a flight of helicopters to follow up on the findings.

When I first started people sniffing I was transferred to Dak To, in the Central Highlands, near the “Tri-border” of Viet Nam, Laos and Cambodia, a very active enemy infiltration area.  Its where the infamous “Ho Chi Minh Trail” entered Viet Nam.  Initially, the APD equipment did not have a credible reputation and so I did not fly very often, maybe a couple times a week.  Usually, APD would be sent in to add to other intelligence gathering information and in an attempt to track possible enemy gathering places.  I had more confidence in my findings than command did and so did my commanding officer, Lt. Col. Gillespie.  He was a strong advocate of the Chemical Corps involvement in the war including Airborne Personnel Detection.

The breakthrough in confidence about the equipment came after one particular mission where we were asked to sniff out an abandoned firebase that was scheduled to be reoccupied.  The APD readings of that base were very high and indicated substantial human activity  although any visuals or other intelligence gathering of activity were unsupportive.  The scuttlebutt was that snoopy was sniffing buffalo dung or something.  When the troops were eventually sent in to re-occupy the base it was discovered to be heavily booby trapped.  Clearly snoopy had smelled something that no one else had.  From that point on, snoopy was in much more demand.

During this time, the ADP equipment was upgraded to a more accurate model, one that took more samples faster.  It was still necessary to gather the samples at treetop level, and still necessary to fly “low and slow” to gather them.  We typically flew with three other ships, two gun ships that trailed
us and a chase ship flying high that directed us and marked the readings on a map to detect patterns.  I was told that an enemy pamphlet was once found that described that flight pattern and offered a bounty on the low flying ship, so apparently the bad guys realized what we were doing, or that we were doing something they'd prefer us not to be.

One discrepancy between our tactics and those described by Galkie is that we had fairly rigorous rules about the patterns we flew.  Since the APD detected different kinds of activity, including engine exhaust, we flew in a pattern upwind and perpendicular to the prevalent air currents in order not to pick up our own exhaust.  The gun ships also had to be cognizant of this pattern and so were restricted from flying into our up-pattern space.  

Note:  I have inserted some of Jack's pictures with the above two pictures showing the entire machine and then the two meters, which gave the operator the readings he then had to interpolate.  I do not know why his equipment was different that the one we used.  The other pictures are of how they prepare a CS Gas drop, this one out of the back of a Chinook Helicopter I believe.  This made for a predictable flight path that could be scary if you thought about it.  Picture a lone enemy gunman watching us go back and forth as if we were spraying crops or something but in the distinctive group of low ship, followed by a gun ship, followed by another gun ship and a chase ship high above, all moving at a very tractable speed.  He could just wait for us to fly past, knowing where and when we would be passing, and then just open fire.  That happened several times and made areas with low readings even scarier than those with heavy readings since large contingents of enemy tended to avoid detection by holding their fire and hiding.
     But it got even scarier as tactics evolved.  Initially, we were simply intelligence gatherers.  We'd collect the data and take it back to HQ for analysis and follow-up planning.  We did not usually initiate any action ourselves unless we were fired upon and sometimes not even then since it was a known enemy tactic to try to draw fire upon our own troop placements by shooting at the gun ships when they happen to be flying near our own troops in order to draw fire.  Again, one or two enemy troops who happened to be near our troops could cause a lot of trouble and potentially friendly fire upon them.  This was particularly tricky if  Viet   Namese (ARVN) troops were in the area since they were not known for their coordination.  It required a lot of command coordination for which we didn't always have the right information.  You've heard of “free fire zones”, well there were also “no fire zones”, even if fired upon.  These were very frustrating, particularly to the gunners (although they did tend to like free fire zones).

As evidence mounted that the APD was indeed detecting humans on the ground pretty accurately, the tactics evolved to more search and destroy rather than simply gather intelligence.  I believe I could smell as few as a couple or three humans if they had been around very long, and certainly a large number of humans gathering (Ammonia is also found in other body effluents such as urine), but also such sources as a launching zone for mortars or rockets or smoke from campfires or marijuana “parties”.  I have no idea how many enemy troops I located during my tour, but I'm sure it runs into the thousands.

And so a team was formed, the S.C.O.R.P.I.O.N team, which is an acronym for Special Combined Operations for Personnel Identification and Overt Neutralization.  This team's mission was to basically “sniff them out and snuff them out”.  We shifted from flying mostly in Huey’s (UH-1x), to Loaches (OH-6x) with a few field modifications on them to mount the equipment efficiently and allow for low-level recon.  The chase ship was loaded with tear gas weaponry that could cover a couple football fields in tear gas.  We were accompanied by two Cobra (AH-1x) gun ships and typically were assigned AO’s highly suspected of harboring enemy troops.  We would fly our snoopy pattern, then determine the most likely areas where we could draw them out.  The two Loaches would then return to the treetops and hover, using the prop wash to blow   the foliage back.  The objective was to make visual contact or draw fire to positively identify a target location.  This was done 
with the Cobras circling the area literally with our hover ships in their sites.  Although we were armed with our M-16s on the deck, our strategy was to immediately vacate the area when fired upon and leave the heavy work to the gun ships.  If things got real interesting, we would call in artillery or air strikes.  A few times this was followed up by even more intense ground operations.
     I flew over 500 missions in Viet Nam, some of which were tear gas drops or defoliation, but mostly they were snoopy missions.  I was shot down with my trainer, Chuck Whalen, in September and he stopped flying after that.  In October another snoopy, a close friend in fact, Warren Haugen, was shot down and killed, which persuaded the only other snoopy operator in the  Highlands (II Corps), Pete 
James, to quit flying.  A gun ship on the SCORPION team was shot down in about February killing both occupants, which dissuaded others from volunteering until a new batch of “volunteers” were 
recruited in March or April.  What this meant to me is that between about December ’68 till April ’69 I was the only snoopy operator in the area and so I flew just about every day with a SCORPION team, often several missions in a day depending on activity.  Not all missions were hot, but we 
had our share.  I estimate somewhere between 30 and 40 missions came under direct fire.  That's actually less than 10% if you think about it, so mostly, it was just another day in paradise flying on the deck over the jungle looking for trouble.  Note:  Jack sent me this picture of him taken just after he received a round to the chest.  You can see the bullet hole between his lower neck and the top portion of that little square pouch area of his chicken plate.  I was just a tekkie passenger, but I flew some exciting missions with a lot of very skilled and very brave airmen.  I flew with different pilots and crew, and with different units in different places.  I hardly remember their names, but with few exceptions, all of those guys were extremely professional and heroic.  I sincerely believe we accomplished our missions and eradicated many enemy troops who were out to do our buddies and allies harm otherwise.  People called me crazy for doing what I did over there, but for me, it was my unique niche and I really thought I was doing some good.  I'm just now coming to grips with it myself.  Thanks Galkie!

Jack Inman  (
SP-4, 4th ID Chem
Camp Enari, Pleiku, RVN
July ’68-July ‘69