Runway warning lights at Tokyo Haneda airport were reportedly broken when the Japan Airlines collision happened

• Runway warning lights at Tokyo's Haneda airport weren't working Tuesday, reports say. 
• The lights tell pilots when a runway is clear. 
• A Japan Airlines jet collided with a coast guard plane Tuesday, killing five people. 

Warning lights that tell pilots when a runway is clear weren't working at Tokyo's Haneda airport when a passenger jet collided with a coast guard plane, according to data.

A NOTAM message issued on December 25, which contains important updates on flight services, says the "stop bar" lights that warn pilots not to head onto the runway at the wrong time had malfunctioned.