PENETRATED ATA; NO CONTACT.

Narrative

I AM AN AG PLT WITH 10 YRS EXPERIENCE; BASED IN GRAND FORKS; ND. I WAS SENT TO IOWA (TO A TOWN CALLED AMANA; 15 MI SW OF CID) TO HELP A LCL APPLICATOR DURING THE RECENT INSECT INFESTATION. ON SEVERAL OCCASIONS PRIOR TO HIS INCIDENT; I WAS SENT TO SPRAY FIELDS INSIDE CID'S CTL ZONE. EACH TIME I WAS TOLD THAT CONTACT WOULD BE MADE TO THE TWR BY PHONE; AND IT WAS. ON THE MORNING OF 8/XX/88; I WAS GIVEN SEVERAL MAPS WITH FIELD DESCRIPTIONS I WAS NOT FAMILIAR WITH. ENRTE I DISCOVERED THAT THE FIELDS LAY WITHIN CID'S CTL ZONE; JUST TO THE N. I CIRCLED THE CTL ZONE AND ENTERED FROM THE N (I ASSUMED THAT CONTACT HAD BEEN MADE AS USUAL). AS THE FIELDS CAME INTO VIEW I NOTICED 1 FIELD LAY DIRECTLY OFF THE END OF RWY 13. I ALSO NOTICED THAT ACFT WERE USING RWY 27 (1/2 MI FURTHER S). I DECIDED THAT I SHOULD SPRAY THE CLOSEST FIELD FIRST FOR 2 REASONS: 1) SINCE TFC WAS LIGHT AND USING A DIFFERENT RWY THAN 13; IT WOULD BE THE MOST OPPORTUNE TIME; AND 2) IT WAS THE CLOSEST FIELD (THE OTHERS WERE OVER 1 MI AWAY); SO THE TWR WOULD SEE ME MOVING FARTHER AWAY INSTEAD OF CREEPING CLOSER. THE FIELD THAT I SPRAYED WAS PARALLEL TO RWY 27; BUT ONLY 1/8 MI OFF THE END OF RWY 13. AS A PRECAUTION TO AVOID UNEXPECTED TFC; ALL MY TURNS WERE MADE TO THE N AT ALTS OF ABOUT 50' AGL (LOWER THAN NORMAL 150-200') AND AT NO TIME WAS THE ACFT ABOVE 10' AGL WHILE DIRECTLY IN LINE WITH THE RWY (WELL BELOW NORMAL APCH OR DEP TFC). I LEFT THE AREA AS I ENTERED FROM THE N. UPON RETURNING TO AMANA AND DISCOVERING THAT NO CONTACT WAS MADE; I CALLED THE TWR TO EXPLAIN. EVEN THOUGH TFC WAS LIGHT (2 ARRS; 6 DEPS); THE TWR PEOPLE WERE SOMEWHAT BELLIGERENT. I REALIZE THAT I SHOULD HAVE CALLED THE TWR MYSELF INSTEAD OF ASSUMING IT WAS DONE (AS I HAVE ON ALL OTHER SUBSEQUENT OPS); AND I DID PENETRATE A CTL ZONE; BUT I THINK THAT TWR PERSONNEL SHOULD BE AWARE OF ALL TYPES OF ACFT OPS AND THE PROBS EACH HAS WHEN SHARING AIRSPACE. NON RADIO EQUIPPED ACFT HAVE MORE PROBS OF AN UNEXPECTED NATURE WHEN WORKING REGULARLY AROUND CTL ZONES AND LACK OF COMS CAN CAUSE MISUNDERSTANDINGS.