Dani
a) these sensors are not fire detections (like they are e.g. in the engine nacelles), but smoke detection systems. b) yes, they are relatively reliable,
In pedant mode, the engine nacelle detectors are (or at least were when I was in the industry) actually heat detectors, either firewire (coaxial steel with a glass dielectric), bi-metallic or other sensors.
in the outside world it happens from time to time
Exactly why I qualified my statement regarding physical damage. but how frequently is that going to create an in flight false alarm?
I think the biggest damage issue we used to have was on military aircraft with fitters knocking / leaning on the firewire on maintenance intensive equipment
I'm talking here mostly about detection systems in smaller airliners, not those in Airbus and Boeings.
I was talking about airbus, Boeing, Military etc but I would have hoped the systems would be similar
On a less defensive basis
I agree smoke detectors of various types are generally less reliable, but we had very few reports of false alarms (but I am going back to the early 80's when fewer devices were fitted)
I'd be interested to know what the general reliability is now.