HU50 PLT HAD A NEAR GND COLLISION AT AN UNCTLED FIELD.

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ACFT #1; MD500 WAS PERFORMING PRACTICE TOUCHDOWN AUTOROTATIONS TO RWY 24 (THE ACTIVE RWY) AT ABOUT THE 1000 FT MARKER. WIND WAS 250 DEGS; ESTIMATE 10-15 KTS. NO OTHER ACFT IN PATTERN. HELI MADE VOICE RPTS PRIOR TO EACH LNDG. AT XA15; A GND OBSERVED RADIOED THE HELI THAT 'YOU HAVE AN ACFT LNDG CLOSE BEHIND YOU.' THE HELI HAD JUST LANDED AND WAS SPOOLING UP IN ORDER TO TKOF. CFI TOOK CTL; LIFTED TO LOW HOVER AND TURNED ACFT SLIGHTLY IN TIME TO SEE ACFT #2; A PIPER PA23 APACHE; MODIFIED WITH POINTED NOSE AND CLIPPED VERT STABILIZER; ON SHORT FINAL TO MY APPROX POS ON RWY. BOTH PLTS IN ACFT HEARD NO RADIO XMISSIONS FROM THE PIPER. HELI HASTILY HOVER-TAXIED CLR OF RWY TO AVOID LNDG TFC. AIRPLANE MADE SLIGHT ARC AROUND TAIL OF HOVER TAXIING HELI AND CONTINUED LNDG; ROLLOUT AND TAXI BACK TO HANGAR/PARKING. HELI MADE A WIDE ORBIT OVER THE PARKING AREA AT 500 FT AGL WELL S OF THE ACTIVE RWY; AND WATCHED PLT PARK PA23 IN FRONT OF ONE OF THE HANGARS. AFTER A SECOND WIDE ORBIT; THE PLT HAD PUT THE PA23 IN THE HANGAR AND DRIVEN OFF. WITNESS ON GND (WHO GAVE WARNING WITH HAND-HELD RADIO) SAID THE PIPER MADE NO XMISSIONS ON UNICOM; MADE A VERY STEEP; ARCING DOWNWIND TO FINAL TURN; MUCH TIGHTER THAN THE USUAL AIRPLANE PATTERN. SIMILAR TO A CARRIER APCH. THIS HELI IS BASED HERE AT THIS ARPT AND THE COMPANY HAS BEEN PERFORMING SIMILAR OPS FOR NEARLY 20 YRS. THERE HAVE NEVER BEEN ANY COMPLAINTS ABOUT THE HELI OPS. THIS IS A VERY LOW DENSITY ARPT; WITH ONLY A FEW AIRPLANE OPS EACH DAY. THE PIPER IS BASED HERE; ALSO. WHAT CAUSED THIS NEAR MISHAP? THE PLT OF THE FIXED WING DID NOT STAY AROUND LONG ENOUGH FOR ME TO DISCUSS IT WITH HIM. I DROVE OVER TO THE HANGAR AFTER THE FLT TO TRY TO MEET HIM; BUT HE WAS GONE. DID HE NOT SEE THE HELI SITTING ON THE RWY FOR ALL OF 30 SECONDS AFTER LNDG WHILE SPOOLING UP THE ROTORS? DID THE PA23 PLT HAVE AN ACFT OR PERSONAL EMER THAT CAUSED HIM TO DEVIATE FROM STANDARD AIRPLANE TFC PATTERN/ETIQUETTE AND MAKE A HASTY APCH? WAS IT 'ROAD RAGE' TRANSLATED TO 'RWY RAGE'...THAT DAMMED HELI IS SITTING ON MY RWY...I'LL SHOW HIM!' WHY DID THE PA23 PLT NOT USE THE CTAF? GRANTED; AT THIS ARPT; ONE CAN HEAR AT LEAST 5 OTHER ARPTS ALL ON THE SAME FREQ 122.8 WITHIN A 50 MI RADIUS.