DCA: late takeoff & go-around due to radio interference

[eboelter]

KDCA tower at 1950 UTC on 9 January 2019

[VASAviation]

Thank you for sharing, eboelter.

Is it known the cause of the interference? It sounds like a hot mic at some point but I'm not really sure.

[flyflyfly]

Certainly sounded like a hot mike. You can hear the usual humming sound of two transmitters interfering. Also, there's some background noise suggesting it's a hot mike.

The hot mike could have been in 5512, the aircraft sitting on the runway waiting for its takeoff clearance: after the event they said "5512, we never heard *any* transmission...". Well, when there's a hot mike, there's usually only exactly one aircraft which did not hearing anything... Everyone else would at least have heard some humming and garbled comms...

[eboelter]

I wasn't clear what the tower meant by his reference to working a helicopter and it being an issue at "local control".  I wonder if light guns were used at any point? 

Also, unrelated, it seems to me KDCA is using runway 4 more frequently.  I'd be curious to find out how its use is determined if anyone knows.