Fire Warning Test B733/4 vs B738
I have a question which is driving me nuts.
When conducting the engine/apu fire warning test on the B737-300 and 400, the fire warning lights on the glareshield and the fire warning handles on the centre pedestal illuminate together.
On the B737-800 the fire warning lights on the glareshield seem to light up approximately 1-1.5 seconds before the fire warning handles on the centre pedestal.
I know it is not much but it is definitely a noticeable difference, generally because I cancel the warning and then have to do it again when it is set off a second time by the fire warning handles.
Does anyone know the difference in the warning system that causes this?