So let me get this straight 4 miles out with an engine fire exactly who would at this stage get onto the cabin interphone to confirm it ?
The flight crew will be flying the plane and putting the fire out and preparing for a single engine landing with more flap than is practiced in the sim as flap 30 will have been selected by 4 miles .
if cabin crew think the flight crew will be able to talk to them at this stage they need more crm trng .
Oh and I believe atc have binoculars so seeing smoke at 4 miles will be possible .