MD90 IN GATE ALLEYWAY HAVING PROB WITH SLATS. BLOCKING ENTRY TO GATE FOR OTHER ACFT. SLAT PROB RESOLVED AND ACFT CLRED TO HOLD SHORT RWY 19L. DOING CHKLIST AND PA ANNOUNCEMENT; CAPT FAILED TO HOLD SHORT OF RWY 19L. CESSNA ON APCH HAD TO GAR.

Narrative

WE HAD PUSHED BACK FROM GATE AT SNA. AFTER ENG START; WE HAD 2 SLAT ABNORMALS THAT TOOK SEVERAL MINS TO RESOLVE USING CHKLIST PROCS. WHILE WE WERE IN THE PROCESS OF ADDRESSING THE SLAT PROBS; GND WAS ASKING US HOW LONG IT WOULD BE BEFORE WE WERE READY TO TAXI. WE REPLIED THAT WE HAD A PROB AND NEEDED A FEW MINS. AT THAT TIME WE WERE NOSE TO NOSE WITH 2 INBOUND ACFT AND GND NEEDED US TO MOVE TO ALLOW THEM TO PARK. WE RESOLVED OUR SLAT PROB AND NOTIFIED GND THAT WE COULD TAXI. THEY ADVISED US TO CONTACT TWR AND TWR INSTRUCTED US TO TURN R ON TXWY L AND HOLD SHORT OF RWY 19L. I BEGAN THE TAXI CHK AND MADE OUR 'NOISE ABATEMENT' PA TO THE PAX. I REALIZED TOO LATE THAT WE WERE HALFWAY ACROSS RWY 19L. TWR SENT A CESSNA ON FINAL TO RWY 19L AROUND AND WE HURRIED ACROSS AND HELD SHORT OF RWY 19R. HUMAN PERFORMANCE CONSIDERATIONS: OBVIOUSLY; WE WERE AT FAULT AND THE MISTAKE WAS SERIOUS. CONTRIBUTING FACTORS: 1) DUE TO THE SHORT RWY AT SNA AND OUR TKOF WT; WE HAD BEEN ISSUED A NON STANDARD TKOF FLAP SETTING IN OUR WT AND BAL PAPERWORK. WHEN LOWERING THE FLAPS/SLATS WE HAD 2 ABNORMALS THAT DEMANDED ATTN. 2) THE TXWYS AND GATE AREAS AT SNA ARE VERY CONFINED AND WE WERE THE SOURCE OF INBOUND DELAYS. GND CTL WANTED US OUT ASAP. 3) TOTAL DISTANCE FROM THE GATE TO TKOF POS IS APPROX 100 YDS SO THINGS HAPPEN FAST. IN ADDITION TO STANDARD PUSHBACK/START; AFTER START; TAXI AND BEFORE TKOF CHKLIST; A PA IS SUGGESTED TO INFORM THE PAX ABOUT THE STEEP CLB OUT AND PWR REDUCTION ON DEP. 4) THE CAPT WAS ACCUSTOMED TO HEARING; 'TURN R ON TXWY L AND HOLD SHORT OF RWY 19R.' ALTHOUGH HE HEARD THE PROPER INSTRUCTIONS; HE WAS EXPECTING TO HEAR SOMETHING ELSE. 5) I FAILED TO BACK HIM UP SINCE I WAS INVOLVED IN OTHER DUTIES. CONCLUSION: WE TELEPHONED SNA TWR AFTER LNDG AT SLC AND APOLOGIZED. THEY SAID NOT TO WORRY; THEY WERE NOT ISSUING A VIOLATION. THE LESSONS LEARNED FROM THIS INCIDENT WILL BE REMEMBERED FOR THE REST OF MY CAREER.