Narrative:

We were landing on runway 27 in bos, VFR. ATIS stated lahso in effect, but unless otherwise stated, the full runway would be usable. About 1 mi away from landing I noticed a B757 landing on the 22's (I assumed runway 22R) because we were never informed of landing traffic on runway 22L when we were cleared to land, so I mentioned it to my first officer (PF) as an FYI. After a good landing I asked the first officer where the B757 was, because it was out of my view. He said he landed on runway 22L. I immediately took the controls and braked hard. We were then cleared across runway 22L on txwys south, and west, cross runway 22R. Everything turned out fine. The main reason I'm writing this is that I landed on a runway with landing traffic on a crossing runway and I didn't now he was going to be there and it surprised me. Callback conversation with reporter revealed the following information: reporter stated the other aircraft was a B757 landing on runway 22L with instructions to hold short of runway 27. He said after coming to a stop on the runway, they were then cleared to cross runway 22L. He said the B757 did hold short of the runway as instructed. He said the controller apologized for not informing them of the lahso operation.

Related reports:

Google
 

Original NASA ASRS Text

Title: WHILE LNDG BOS RWY 27, A CRJ200 CREW BRAKE HARD WHEN THEY VISUALLY SPOT A B757 LNDG ON XING RWY 22L.

Narrative: WE WERE LNDG ON RWY 27 IN BOS, VFR. ATIS STATED LAHSO IN EFFECT, BUT UNLESS OTHERWISE STATED, THE FULL RWY WOULD BE USABLE. ABOUT 1 MI AWAY FROM LNDG I NOTICED A B757 LNDG ON THE 22'S (I ASSUMED RWY 22R) BECAUSE WE WERE NEVER INFORMED OF LNDG TFC ON RWY 22L WHEN WE WERE CLRED TO LAND, SO I MENTIONED IT TO MY FO (PF) AS AN FYI. AFTER A GOOD LNDG I ASKED THE FO WHERE THE B757 WAS, BECAUSE IT WAS OUT OF MY VIEW. HE SAID HE LANDED ON RWY 22L. I IMMEDIATELY TOOK THE CTLS AND BRAKED HARD. WE WERE THEN CLRED ACROSS RWY 22L ON TXWYS S, AND W, CROSS RWY 22R. EVERYTHING TURNED OUT FINE. THE MAIN REASON I'M WRITING THIS IS THAT I LANDED ON A RWY WITH LNDG TFC ON A XING RWY AND I DIDN'T NOW HE WAS GOING TO BE THERE AND IT SURPRISED ME. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THE OTHER ACFT WAS A B757 LNDG ON RWY 22L WITH INSTRUCTIONS TO HOLD SHORT OF RWY 27. HE SAID AFTER COMING TO A STOP ON THE RWY, THEY WERE THEN CLRED TO CROSS RWY 22L. HE SAID THE B757 DID HOLD SHORT OF THE RWY AS INSTRUCTED. HE SAID THE CTLR APOLOGIZED FOR NOT INFORMING THEM OF THE LAHSO OP.

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.