Originally Posted by
Sir Korsky
If I remember rightly, the 139 floats are immersion activated with manual back up. My money on collective F up.
Activation from the collective mounted switch requires a three stage action, arm floats, lift the collective switch guard then press the button. If the floats are armed, the ‘float test’ button being pressed inadvertently, (by a flight board or iPad etc) would also make the circuit, which could be more likely.