Narrative:

The event occurred at the conclusion of an instrument training flight. We had taxied clear of runway 19R at sna airport and were holding short of runway 19L on taxiway H. We had just pulled up short, and had been holding for less than 1 min, waiting for our clearance to cross the runway. Also on taxiway H was a cessna cardinal immediately to our left, holding short of runway 19R. Because of the cardinal, it was difficult for us to turn our aircraft to gain a clear view of the traffic landing and departing on runway 19L. We heard a radio call from the tower controller. What we thought he had said was 'cessna XXX continue.' I hesitated, uncertain, as I was expecting a different phrasing for our crossing clearance. My student acknowledged with 'XXX crossing runway 19L,' and crossed the runway. After crossing, we contacted ground control, and taxied back to parking. The ground controller said nothing to indicate we had made any errors. A phone call from the tower later that day revealed what had actually happened. The radio call had in fact been 'air carrier XXX continue,' intended for an aircraft which had just checked in with the tower on the ILS. The similar sounding call sign had led us to believe that we had been cleared to cross the runway. After my student acknowledged the radio call, the tower controller didn't call back to correct our error, probably because of the speed with which my student crossed the runway and the congestion on the frequency. In addition, because of my seating position on the right side of the cockpit of our high wing aircraft, combined with our poor view of the traffic on runway 19L (on our left side), I didn't see the aircraft landing on runway 19L. According to the controller I spoke with, this had led to a loss of separation and a near miss of some 1500 ft. The primary cause of the incursion was the misunderstanding caused by the similar sounding call signs, and a willingness to proceed while uncertain of the instructions received. Add to it a poor view of the runway, and these factors which by themselves probably won't cause an incident, combine to cause an incident.

Related reports:

Google
 

Original NASA ASRS Text

Title: RWY INCURSION AT SNA, CA.

Narrative: THE EVENT OCCURRED AT THE CONCLUSION OF AN INST TRAINING FLT. WE HAD TAXIED CLR OF RWY 19R AT SNA ARPT AND WERE HOLDING SHORT OF RWY 19L ON TXWY H. WE HAD JUST PULLED UP SHORT, AND HAD BEEN HOLDING FOR LESS THAN 1 MIN, WAITING FOR OUR CLRNC TO CROSS THE RWY. ALSO ON TXWY H WAS A CESSNA CARDINAL IMMEDIATELY TO OUR L, HOLDING SHORT OF RWY 19R. BECAUSE OF THE CARDINAL, IT WAS DIFFICULT FOR US TO TURN OUR ACFT TO GAIN A CLR VIEW OF THE TFC LNDG AND DEPARTING ON RWY 19L. WE HEARD A RADIO CALL FROM THE TWR CTLR. WHAT WE THOUGHT HE HAD SAID WAS 'CESSNA XXX CONTINUE.' I HESITATED, UNCERTAIN, AS I WAS EXPECTING A DIFFERENT PHRASING FOR OUR XING CLRNC. MY STUDENT ACKNOWLEDGED WITH 'XXX XING RWY 19L,' AND CROSSED THE RWY. AFTER XING, WE CONTACTED GND CTL, AND TAXIED BACK TO PARKING. THE GND CTLR SAID NOTHING TO INDICATE WE HAD MADE ANY ERRORS. A PHONE CALL FROM THE TWR LATER THAT DAY REVEALED WHAT HAD ACTUALLY HAPPENED. THE RADIO CALL HAD IN FACT BEEN 'ACR XXX CONTINUE,' INTENDED FOR AN ACFT WHICH HAD JUST CHKED IN WITH THE TWR ON THE ILS. THE SIMILAR SOUNDING CALL SIGN HAD LED US TO BELIEVE THAT WE HAD BEEN CLRED TO CROSS THE RWY. AFTER MY STUDENT ACKNOWLEDGED THE RADIO CALL, THE TWR CTLR DIDN'T CALL BACK TO CORRECT OUR ERROR, PROBABLY BECAUSE OF THE SPD WITH WHICH MY STUDENT CROSSED THE RWY AND THE CONGESTION ON THE FREQ. IN ADDITION, BECAUSE OF MY SEATING POS ON THE R SIDE OF THE COCKPIT OF OUR HIGH WING ACFT, COMBINED WITH OUR POOR VIEW OF THE TFC ON RWY 19L (ON OUR L SIDE), I DIDN'T SEE THE ACFT LNDG ON RWY 19L. ACCORDING TO THE CTLR I SPOKE WITH, THIS HAD LED TO A LOSS OF SEPARATION AND A NEAR MISS OF SOME 1500 FT. THE PRIMARY CAUSE OF THE INCURSION WAS THE MISUNDERSTANDING CAUSED BY THE SIMILAR SOUNDING CALL SIGNS, AND A WILLINGNESS TO PROCEED WHILE UNCERTAIN OF THE INSTRUCTIONS RECEIVED. ADD TO IT A POOR VIEW OF THE RWY, AND THESE FACTORS WHICH BY THEMSELVES PROBABLY WON'T CAUSE AN INCIDENT, COMBINE TO CAUSE AN INCIDENT.

Data retrieved from NASA's ASRS site as of July 2007 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.