PIPER AEROSTAR CPR PLT INADVERTENTLY CROSSES THE RWY TO WHICH HE IS CLRED DUE TO DISTR OF GND CTLR ADVISING A LEARJET TO FOLLOW HIM TO ANOTHER RWY THEN THAT TO WHICH HE WAS CLRED.

Narrative

ST PAUL DOWNTOWN ARPT HAS A RATHER UNUSUAL RWY CONFIGN. IT HAS BOTH A RWY 32/14 AND A RWY 31/13. THEY ARE NOT PARALLEL; BUT THE MUCH SHORTER RWY 31 LIES SKEWED AND NEAR THE MIDDLE OF RWY 32. I HAD FLOWN IN THE SAME DAY AT XE30 LCL AFTER A 3 HR FLT; WHICH DEPARTED PTK AT XC30 (I'D BEEN UP SINCE XA00). AFTER A DAY OF BUSINESS MEETINGS AND ABOUT 100 MI OF DRIVING; I PREPARED TO DEPART STP AT ABOUT XB30. FATIGUE DID PLAY A PART. I WAS PARKED ON THE E SIDE OF THE FIELD. I HAD A RADIO PROB; WHICH CAUSED SOME PROBS GETTING CLRNC. I THEN CONTACTED GND CTL AND; AFTER BEING ASKED TO QUICKLY CLR THE RAMP FOR AN ARR; I WAS TOLD TO 'TAXI TO RWY 31.' I UNCONSCIOUSLY NOTED THAT ALL ARR AND DEPARTING TFC I SAW WAS USING RWY 32. AS I WAS TAXIING; THE CTLR TOLD A LEAR TO 'FOLLOW THE AEROSTAR TO RWY 32.' MY 'MIND' NOTED THE REF. YES; I WAS CONFUSED AND SHOULD HAVE ASKED FOR CLARIFICATION; BUT I DID NOT. TXWY E LITERALLY WINDS AROUND THE E END OF THE FIELD. IT CROSSES THE END OF RWY 27; THEN RWY 31; AND ENDS AT RWY 32. I CROSSED RWY 27; AND THEN CROSSED RWY 31. THE CTLR WAS TALKING TO SOMEONE ELSE AND DIDN'T NOTICE MY ERROR. AS I WAS 1/2 WAY TO RWY 32 HE CALLED AND TOLD ME OF THE ERROR. I OFFERED TO TURN AROUND BUT HE TOLD ME TO PROCEED TO RWY 32. I DEPARTED NORMALLY. I WILL NOT DENY MY RESPONSIBILITY FOR THE ERROR; BUT FEEL THERE ARE SEVERAL FACTORS: 1) MY FATIGUE. 2) THE CALL FROM GND FOR AN AIRPLANE TO 'FOLLOW' ME TO RWY 32. 3) THE VERY PECULIAR LAYOUT OF THE FIELD. THIS IS THE FIRST TIME IN 11 YRS AND 2200 HRS AS PIC THAT I HAVE COMMITTED A RWY INCURSION ERROR. I'LL SIMPLY HAVE TO LISTEN BETTER IN THE FUTURE.