Narrative:

Lga was landing aircraft on runway 31 and departing aircraft on runway 4. We were cleared into position on runway 4 to hold, while another aircraft was landing on runway 31, the intersecting runway. The aircraft landed on runway 31 and was cleared onto a taxiway prior to runway 4. The tower then cleared us for takeoff on runway 4. The first officer was flying, I set takeoff thrust and we started moving down the runway. A few seconds after we started our takeoff roll I saw an medium large transport slowly taxiing onto our runway from runway 31. I aborted the takeoff just as the tower told us to abort. I stopped the aircraft and taxied clear of the runway, well clear of the medium large transport on runway 4. The crew of the wandering medium large transport apologized to lga tower for missing the taxiway. Lga tower apologized to us for the incident. I guess the procedure should be not to clear an aircraft for takeoff on runway 4 at lga unless the aircraft landing on runway 31 has actually cleared runway 31 and is not still hunting for the taxiway.

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Original NASA ASRS Text

Title: ACR-MLG CROSSED TKOF RWY DURING LNDG ROLL CAUSING ACR-LGT ABORT.

Narrative: LGA WAS LNDG ACFT ON RWY 31 AND DEPARTING ACFT ON RWY 4. WE WERE CLRED INTO POS ON RWY 4 TO HOLD, WHILE ANOTHER ACFT WAS LNDG ON RWY 31, THE INTERSECTING RWY. THE ACFT LANDED ON RWY 31 AND WAS CLRED ONTO A TXWY PRIOR TO RWY 4. THE TWR THEN CLRED US FOR TKOF ON RWY 4. THE F/O WAS FLYING, I SET TKOF THRUST AND WE STARTED MOVING DOWN THE RWY. A FEW SECS AFTER WE STARTED OUR TKOF ROLL I SAW AN MLG SLOWLY TAXIING ONTO OUR RWY FROM RWY 31. I ABORTED THE TKOF JUST AS THE TWR TOLD US TO ABORT. I STOPPED THE ACFT AND TAXIED CLR OF THE RWY, WELL CLR OF THE MLG ON RWY 4. THE CREW OF THE WANDERING MLG APOLOGIZED TO LGA TWR FOR MISSING THE TXWY. LGA TWR APOLOGIZED TO US FOR THE INCIDENT. I GUESS THE PROC SHOULD BE NOT TO CLR AN ACFT FOR TKOF ON RWY 4 AT LGA UNLESS THE ACFT LNDG ON RWY 31 HAS ACTUALLY CLRED RWY 31 AND IS NOT STILL HUNTING FOR THE TXWY.

Data retrieved from NASA's ASRS site as of August 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.