Critical runway warning lights that warn pilots not to proceed onto an active runway were unserviceable at Haneda Airport and are the focus of crash investigators looking into the accident on Tuesday night in which five people died.

AirlineRatings.com Editor-in-Chief Geoffrey Thomas explains the issue below. AirlineRatings.com broke the story of the unserviceable lights

However, there was a Notice To Airmen (NOTAM) warning that the that critical Stop Bar Lighting were unserviceable for a series of taxiway to runway junctions (C1 to C14).

Did the Coast Guard pilot assume he could enter the runway as there were no Stop Bar warning lights on (Below Images)? Did the Coast Guard crew read the NOTAM?

We know that ATC issued the instruction to Taxi and Hold, which was read back. Was the pilot confused about his location and thought he was still on a taxiway as no red warning lights were telling him not to proceed?

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