RWY INCURSION. UNAUTH RWY ENTRY.

Narrative

AFTER LNDG RWY 26 AT YVR; THE CAPT ELECTED TO TURN OFF THE RWY ONTO INTERSECTING RWY 12/30. TWR WAS ALSO USING THIS RWY; AND HAD CLRED A COMMUTER TURBOPROP TO LAND. TWR POINTED OUT OUR CONFLICT AND ADVISED US WE NEEDED SPECIFIC CLRNC TO BE ON RWY 30/12. WE QUICKLY CLRED ONTO A TXWY; AND THE COMMUTER CONTINUED HIS APCH TO LNDG. NO DISCUSSION OF THE CAPT'S INTENT TO USE THE INTERSECTING RWY PRIOR TO HIS TURN. DISCUSSED IT AFTERWARD; AND I EXPRESSED CONCERN WE WERE PROBABLY IN THE WRONG. THE TURNOFF WAS MADE RATHER QUICKLY BEFORE ANYONE ELSE HAD A REAL OPPORTUNITY TO VOICE AN OPINION. SUPPLEMENTAL INFO FROM ACN 267570: SO OBTAINED ATIS INBOUND; BUT NEGLECTED TO INFORM THE CAPT THAT INTERSECTING RWY OPS WERE IN PROGRESS: LNDG ON RWY 26 AND ALSO ON INTERSECTING RWY 12. AFTER LNDG; DECELERATION DID NOT HAVE US SLOW ENOUGH TO TAKE THE INTENDED EXIT OFF OF RWY 26. INSTEAD OF TAXIING 3000 FT MORE TO THE END OF THE RWY; THE CAPT CHOSE TO EXIT ONTO RWY 30; WHICH WAS THE WRONG CHOICE! THE TWR OPERATOR IMMEDIATELY REQUESTED THAT WE CLR RWY 30; AS HE HAD TFC INBOUND TO THAT RWY. CAPT ERRED BY NOT FOLLOWING ATC SECTION 4-12; PARAGRAPH 4.4.4; WHICH STATES '...NO ACFT SHOULD EXIT A RWY ONTO ANOTHER RWY UNLESS INSTRUCTED OR AUTH TO DO SO BY ATC.' HAD THE SO ADVISED THE CAPT THAT INTERSECTING RWY OPS WERE IN PROGRESS; IT WOULD HAVE KEYED THE CAPT TO NOT MAKE THE MISTAKE THAT HE DID.