A DEP B727-200 PIC ALMOST ABORTS THE TKOF FROM DTW RWY 21C WHEN A DC10 IS THOUGHT TO BE SEEN XING THE RWY SOME DISTANCE IN FRONT OF THE B727. PIC SAYS IT WAS ALL AN ILLUSION DURING THIS NIGHT TKOF.

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DURING THE TKOF ROLL ON RWY 21C AT DTW; WE SAW WHAT APPEARED TO BE AN ACFT XING OUR RWY SOMEWHERE DOWNFIELD. WHILE WE WERE STILL BELOW 80 KTS; THE ACFT APPEARED TO BE CLR OF THE RWY; SO I DECIDED IT WAS SAFE TO CONTINUE THE TKOF; BUT WAS CONCERNED THAT A POTENTIAL CONFLICT HAD OCCURRED ON THE RWY. UPON ARR AT DENVER I CONTACTED DTW TWR CHIEF AND HE ADVISED ME THAT THE ONLY ACFT IN THE AREA WAS A DC10 TAXIING WBOUND ON TXWY T. SINCE TXWY T ELEVATION IS AT 60 FT HIGHER THAN THE END OF RWY 21C; I BELIEVE WHAT WE SAW WAS THIS ACFT ON TXWY T; BUT IT HAD THE ILLUSION OF XING OUR RWY. DTW TWR CHIEF ADVISED ME THAT THERE HAD BEEN AT LEAST 4 UNNECESSARY ABORTS ON RWY 21C DUE TO THIS ILLUSION PROB. HE SAID HE WOULD RECOMMEND AN OPS CHANGE AT DTW TWR TO ADVISE FLTS DEPARTING RWY 21C WHEN THERE IS AN ACFT TAXIING ON TXWY T. THIS WOULD PREVENT ANY FUTURE ABORTS WHEN THERE REALLY IS NO TFC CONFLICT. I AM SURE THAT THE DTW REGULARS ARE ALREADY AWARE OF THIS ILLUSION ON RWY 21C; BUT OPERATORS WHO DO NOT USE DTW OFTEN SHOULD BE ADVISED OF THE POTENTIAL FOR THE ILLUSION OF TFC CONFLICT AT NIGHT WHEN DEPARTING RWY 21C.