SOUTH VIET NAM THE MAKESHIFT KILLERS INTO THE VALLEY OF DEATH LAST WEEK FLEW THE 800 . THEY WERE SOUTH VIETNAMESE TROOPS BEING LIFTED BY A COMPANY OF U.S . H-21 TROOP-CARRYING HELICOPTERS TO CLEAN OUT A COMMUNIST-INFESTED JUNGLE HIDEOUT 175 MILES NORTHEAST OF SAIGON . THE REGION WAS A TANGLED, MENACING BATTLEGROUND, WHOSE NAME, LIKE TENNYSON'S BALACLAVA, DERIVES FROM ITS BLOODY HISTORY IN SOUTH VIET NAM'S UGLY GUERRILLA WAR . AS EACH FLIGHT DIPPED INTO THE TINY LANDING ZONE, AN ESCORT OF TWELVE ROCKETCARRYING UH 1-B ( " HUEY " ) CHOPPERS SPRAYED THE SCRUBBY UNDERBRUSH WITH ROCKETS AND MACHINE-GUN FIRE . NOT A SINGLE HOSTILE SHOT WAS RETURNED AS THE TROOPS HIT THE GROUND AND FANNED INTO THE JUNGLE . THE ABSENCE OF ENEMY OPPOSITION IN THE LANDING AREA COULD BE LARGELY TRACED TO VIET CONG FEAR OF THE ROCKET-CARRYING HUEYS . BEFORE THEIR ARRIVAL IN SOUTH VIET NAM LAST FALL, DEVASTATING COMMUNIST GROUND FIRE AGAINST THE LUMBERING, DEFENSELESS H-21S THREATENED TO HALT THE GOVERNMENT'S HELICOPTER AIRLIFT CAMPAIGN, WHICH HAD BEEN THE MOST EFFECTIVE OFFENSIVE TACTIC AGAINST THE RED GUERRILLAS . RELUCTANTLY THE TOP U.S . MILITARY BRASS, WHICH HAD LONG BEEN SKEPTICAL THAT A HELICOPTER COULD EVER BE A DEADLY OFFENSIVE WEAPON, THREW THE NEWLYARRIVED HUEYS INTO COMBAT . THEIR MISSION : TO ESCORT AND PROTECT THE TROOPCARRYING COPTERS . " THE MOST ESSENTIAL UNIT . " SO EFFECTIVE HAVE THE HUEYS BEEN IN COUNTERACTING VIET CONG GROUND FIRE THAT SOME H-21 PILOTS HAVE REFUSED TO CARRY OUT MISSIONS RATHER THAN FLY WITHOUT HUEY ESCORTS . SINCE LAST OCTOBER, THE HUEYS HAVE FLOWN 3,600 SORTIES, FIRED 1,800 ROCKETS AND 200,000 ROUNDS OF MACHINEGUN AMMUNITION, AND KILLED COUNTLESS HUNDREDS OF REDS . TWO ENLISTED MEN OF THE COMPANY (WHOSE OFFICIAL MILITARY DESIGNATION IS UTILITY TACTICAL TRANSPORT COMPANY) HAVE BEEN KILLED IN COMBAT, AND 19 OTHER MEMBERS OF THE 113-MAN UNIT HAVE BEEN AWARDED THE DISTINGUISHED FLYING CROSS . TODAY U.S . MILITARY OFFICIALS ESTIMATE THAT, ALTHOUGH THE VIET CONG HAS DOUBLED ITS ANTIAIRCRAFT EFFORT IN THE PAST YEAR, THE TROOP-CARRYING CHOPPERS ARE SUFFERING 25 PER CENT FEWER HITS THAN BEFORE THE HUEYS ARRIVED ON THE VIET NAM SCENE . " THE HUEYS, " SAYS GENERAL PAUL HARKINS, THE CAPABLE BOSS OF THE 14,000 U.S . ADVISERS IN SOUTH VIET NAM, " ARE THE MOST ESSENTIAL UNIT IN MY COMMAND . " THE IRONY OF THE HUEYS' SUCCESS IS THAT THEY ARE MAKESHIFT KILLERS, ORIGINALLY DESIGNED AS UTILITY AIRCRAFT AND PERSONNEL CARRIERS . BUT HUEY PILOTS BECAME CONVINCED THAT THEIR SPEEDY, MANEUVERABLE CHOPPERS WOULD BE IDEAL SUPPORT AIRCRAFT IN THE KIND OF GUERRILLA WAR SITUATION THAT SOUTHEAST ASIA PRESENTS . ON THEIR OWN, COMPANY PERSONNEL OUTFITTED THEIR HUEYS WITH 16 HOMEMADE ROCKET MOUNTS AND FOUR MACHINE-GUN BRACKETS, PESTERED DUBIOUS BRASS FOR MONTHS TO LET THEM TRY OUT THEIR IDEAS IN ACTION . THE HUEYS' EFFECTIVENESS IS MAINLY THE RESULT OF THEIR ABILITY TO CHUG RIGHT ALONG IN THE SAME FORMATION WITH THE H-21S . UNLIKE FIXED-WING FIGHTER BOMBERS, WHICH FLY TOO HIGH AND TOO FAST TO PICK OUT SPECIFIC TARGETS AND SOMETIMES DROP NAPALM ON INNOCENT CIVILIANS, THE SLOWCRUISING HUEYS CAN SPOT GROUND FIRE IN THE LANDING ZONE AND MOVE IN TO NEUTRALIZE IT WITH DISCRIMINATING FIRE THAT SPARES NONCOMBATANTS . " IF WE KILL ONE WOMAN OR A CHILD ON A MISSION AND 90 VIET CONG, " SAYS ONE HUEY PILOT, " THEN THAT MISSION IS A FAILURE . " PSYCHOLOGICAL EFFECT . AS A PREVIOUSLY UNTRIED COMBAT INNOVATION, THE HUEYS CAN AFFORD TO EXPERIMENT IN HELIBORNE ASSAULT TACTICS, ARE PROVIDING THE ARMY WITH INVALUABLE OPERATIONAL EXPERIENCE IN NEW DOCTRINES OF GUERRILLA WARFARE . " WE'RE WRITING THE BOOK OF TACTICS OURSELVES, " SAYS MAJOR IVAN SLAVICH, 35, COMMANDING OFFICER OF THE U.T.T . COMPANY . IN COMBAT, THE HUEYS USUALLY FLY A CIRCULAR " DAISY CHAIN " PATTERN SO THAT EACH SHIP IS ALWAYS COVERED BY THE CHOPPER IMMEDIATELY BEHIND IT . " OUR MACHINE GUNS HAVE MORE ACTUAL KILLING POWER, " SAYS SLAVICH . " BUT OUR ROCKETS SEEM TO HAVE A MUCH GREATER PSYCHOLOGICAL EFFECT ON THE VIET CONG . / THE MAKESHIFT KILLERS WITH THEIR MANEUVERABILITY, THE HUEYS CAN SLIDE BACK AND FORTH JUST A FEW FEET OVER THE SUN-SCORCHED RICE FIELDS, SORTING OUT THEIR TARGETS LIKE COWBOYS CUTTING STEERS FROM A HERD . ON ONE RECENT MISSION, THE DESPERATE REDS TRIED TO LOB HAND GRENADES INTO THE OPEN SIDE DOORS OF THE LOW-CIRCLING CHOPPERS . WHEN TWO HUEYS TRIED TO BOX IN AND CAPTURE A FLEEING RED GUERRILLA, HE SUDDENLY WHEELED AND HEADED STRAIGHT FOR THEM, A HAND GRENADE IN EACH HAND . A BURST OF GUNFIRE FROM THE CHOPPERS CUT HIM DOWN ; BOTH GRENADES EXPLODED BENEATH HIS BODY . FROM THE DOOR OF A GRASS HUT, A GUERRILLA BLAZED AWAY AT A HOVERING HUEY, MISSED ITS COPILOT BY ONLY A FEW INCHES . THE HUEY'S WINGMAN PLANTED A ROCKET SMACK IN THE DOORWAY OF THE HUT AND BLEW IT TO PIECES . SCARED PRINCESS . THE CHOPPER PILOTS CREDIT SLAVICH FOR THE OUTSTANDING SUCCESS OF THE HUEYS, CALL THEIR OUTFIT " SLAVICH'S PEOPLE . " SON OF A RETIRED SAN FRANCISCO DEMOCRATIC WARD POLITICIAN, SLAVICH SERVED AS A MARINE CORPS ENLISTED MAN AFTER WORLD WAR II, BECAME AN ARMY OFFICER AFTER GRADUATION FROM THE UNIVERSITY OF SAN FRANCISCO IN 1951 . HE WON A COMBAT INFANTRYMAN'S BADGE IN KOREA, BECAME A PILOT IN 1955, TOOK COMMAND OF THE U.T.T . COMPANY LAST NOVEMBER . SLAVICH RUNS AN EASYGOING OUTFIT AT HIS BASE AT THE EDGE OF SAIGON AIRPORT . LIKE TOURISTS, SOME PILOTS TOTE CAMERAS ON MISSIONS, AND SLAVICH HIMSELF USED TO TAKE HIS GERMAN SHEPHERD, PRINCESS, ALONG ON SORTIES UNTIL THE PUP BECAME SO SHELL-SHY THAT SHE NEARLY JUMPED OUT OF THE CHOPPER WHEN THE ROCKETS WERE FIRED . THE PILOTS HAVE A JARGON OF THEIR OWN . THEY " ZAP " THE VIET CONG ON A GOOD DAY, CALL SAIGON " THE VILLE, " EXPRESS FERVENT APPROVAL OF EVERYTHING FROM A GIRL TO A CHOPPER WITH THE WORD " OUTSTANDIN' . " TOP-RANKING VISITORS OFTEN HITCH RIDES ON THEIR FLIGHTS TO GET IN A FEW PERSONAL LICKS AT THE VIET CONG . BRIGADIER GENERAL JOSEPH STILWELL JR., SON OF " VINEGAR JOE, " FREQUENTLY RIDES SHOTGUN IN SLAVICH'S OWN CHOPPER . ONCE, WITH STILWELL ABOARD, SLAVICH HAD TO MAKE AN EMERGENCY LANDING IN A RED-INFESTED AREA . " I WAS SCARED TO DEATH, " SAID SLAVICH . GLAD THE VIET CONG DIDN'T COME ALONG, BECAUSE I KNOW DAMN WELL THAT GENERAL STILWELL WOULD HAVE MADE US FIGHT FOR THE MACHINE INSTEAD OF LETTING US RUN . " / PUCKER UP & PRAY . " DEADLY AS THE HUEYS ARE, THEY HAVE THEIR FAULTS . AS BOTH DOORS MUST BE KEPT WIDE OPEN TO GIVE THE AUTOMATIC RIFLE-TOTING SIDE GUNNERS COMPLETE VISIBILITY, THE BLAST OF THE ROCKETS CREATES AN EAR-SHATTERING DIN IN THE COPTER'S CABIN . EVEN WORSE, THE HUEYS ARE VIRTUALLY UNARMORED, AND ENEMY FLAK CUTS THROUGH THEM EASILY . ALL FOUR CREWMEN NOT ONLY WEAR FLAK VESTS BUT ALSO SIT ON A PILE OF VESTS TO PROTECT PRIVATE PARTS . " WHEN AN ENEMY IS SHOOTING AT YOU AT THAT LOW ALTITUDE, IT'S THE MOST HOPELESS FEELING IN THE WORLD, " SAYS ONE PILOT . " THERE'S NOTHING TO DO BUT PUCKER UP AND PRAY . " BUT BECAUSE OF THE HUEYS' PERFORMANCE, THE ARMY IS NOW ENCOURAGING THE DESIGN OF A MUCH BETTER, ARMORED, ATTACK HELICOPTER, WHICH MIGHT ACHIEVE SPEEDS OF 175 KNOTS AND EMPLOY HEAVIER MACHINE GUNS AND PERMANENTLY INSTALLED TURRETS FOR THE LETHAL ROCKETS . FROM MAJOR SLAVICH COMES THE RATIONALE FOR SUCH AN AIRCRAFT . / WE CAN STAY IN THE SAME ENVIRONMENT AS THE HELICOPTERS WE ARE PROTECTING, " HE SAID . " WE CAN WORK IN CLOSE, WE CAN WORK IN UNLIMITED VISIBILITY, WE CAN VARY OUR AIRSPEED FROM 100 KNOTS TO ZERO . WE CAN SEEK AND FIND A HOSTILE MENACE TO HELICOPTERS BETTER THAN ANYONE ELSE . /