Narrative:

I was wbound on a pipeline patrol at about 300 ft above ground level and about 75 KTS ground speed. The C130 was sbound at an estimated 500 ft above ground level at about 200 KTS ground speed. I first saw the C130 as it emerged from above my right wing (in a blind spot) when he was no more than 500 ft slant range. I turned hard right and descended while the C130 pulled up in a left climbing turn. The C130 continued his turn as if looking for me while I continued wbound at about 200 ft AGL. After several turns to various headings; the C130 continued in a generally southerly direction; still at low altitude. I am not sure the C130 saw me until he was very close. From my 30 yrs experience as a military fighter pilot; with several yrs flying air intercept missions for the north american air defense command; it appeared somewhat likely that the C130 was deliberately trying to intercept me. My transponder was on and operational; squawking 1200 and mode C (altitude). I assume that the C130 was equipped with TCAS which should have been depicting my altitude and range to him. While I understand that the C130 may have been on a low altitude route and was doing nothing illegal; I was also doing nothing illegal and had every right to be where I was patrolling a route I have flown for 17 yrs. I was not able to see the tail markings on the C130 during my (and his) maneuvering; but the aircraft was definitely military and looked very much like the ones I frequently see at davis-monthan AFB in tucson. As far as avoiding the situation in the future; I can't think of anything I could do other than continue to use good lookout doctrine. It is not often in the high desert that one sees other aircraft at 300-500 ft AGL other than a helicopter or two and it is easy to be lulled into thinking you are the only one out there. Military aircraft and others equipped with TCAS or other electronic aids should certainly be aware of other transponder equipped aircraft in their vicinity and make every effort to avoid conflict. Aircraft under control by military or civilian agencies should also be aware that ground radar does not always pick up low flyers; even those with operating xponders. Again; good lookout doctrine is in order.

Related reports:

Google
 

Original NASA ASRS Text

Title: PA18 PILOT AT 300 FEET AGL EAST OF LSB REPORTS CRITICAL CONFLICT WITH C130.

Narrative: I WAS WBOUND ON A PIPELINE PATROL AT ABOUT 300 FT ABOVE GND LEVEL AND ABOUT 75 KTS GND SPD. THE C130 WAS SBOUND AT AN ESTIMATED 500 FT ABOVE GND LEVEL AT ABOUT 200 KTS GND SPD. I FIRST SAW THE C130 AS IT EMERGED FROM ABOVE MY R WING (IN A BLIND SPOT) WHEN HE WAS NO MORE THAN 500 FT SLANT RANGE. I TURNED HARD R AND DSNDED WHILE THE C130 PULLED UP IN A L CLBING TURN. THE C130 CONTINUED HIS TURN AS IF LOOKING FOR ME WHILE I CONTINUED WBOUND AT ABOUT 200 FT AGL. AFTER SEVERAL TURNS TO VARIOUS HDGS; THE C130 CONTINUED IN A GENERALLY SOUTHERLY DIRECTION; STILL AT LOW ALT. I AM NOT SURE THE C130 SAW ME UNTIL HE WAS VERY CLOSE. FROM MY 30 YRS EXPERIENCE AS A MIL FIGHTER PLT; WITH SEVERAL YRS FLYING AIR INTERCEPT MISSIONS FOR THE NORTH AMERICAN AIR DEFENSE COMMAND; IT APPEARED SOMEWHAT LIKELY THAT THE C130 WAS DELIBERATELY TRYING TO INTERCEPT ME. MY XPONDER WAS ON AND OPERATIONAL; SQUAWKING 1200 AND MODE C (ALT). I ASSUME THAT THE C130 WAS EQUIPPED WITH TCAS WHICH SHOULD HAVE BEEN DEPICTING MY ALT AND RANGE TO HIM. WHILE I UNDERSTAND THAT THE C130 MAY HAVE BEEN ON A LOW ALT RTE AND WAS DOING NOTHING ILLEGAL; I WAS ALSO DOING NOTHING ILLEGAL AND HAD EVERY RIGHT TO BE WHERE I WAS PATROLLING A RTE I HAVE FLOWN FOR 17 YRS. I WAS NOT ABLE TO SEE THE TAIL MARKINGS ON THE C130 DURING MY (AND HIS) MANEUVERING; BUT THE ACFT WAS DEFINITELY MIL AND LOOKED VERY MUCH LIKE THE ONES I FREQUENTLY SEE AT DAVIS-MONTHAN AFB IN TUCSON. AS FAR AS AVOIDING THE SITUATION IN THE FUTURE; I CAN'T THINK OF ANYTHING I COULD DO OTHER THAN CONTINUE TO USE GOOD LOOKOUT DOCTRINE. IT IS NOT OFTEN IN THE HIGH DESERT THAT ONE SEES OTHER ACFT AT 300-500 FT AGL OTHER THAN A HELI OR TWO AND IT IS EASY TO BE LULLED INTO THINKING YOU ARE THE ONLY ONE OUT THERE. MIL ACFT AND OTHERS EQUIPPED WITH TCAS OR OTHER ELECTRONIC AIDS SHOULD CERTAINLY BE AWARE OF OTHER XPONDER EQUIPPED ACFT IN THEIR VICINITY AND MAKE EVERY EFFORT TO AVOID CONFLICT. ACFT UNDER CTL BY MIL OR CIVILIAN AGENCIES SHOULD ALSO BE AWARE THAT GND RADAR DOES NOT ALWAYS PICK UP LOW FLYERS; EVEN THOSE WITH OPERATING XPONDERS. AGAIN; GOOD LOOKOUT DOCTRINE IS IN ORDER.

Data retrieved from NASA's ASRS site as of May 2009 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.