The day a faulty temp probe grounded a whole 737 fleet in Phoenix
Last Thursday I traced a bad RTD sensor that was reading 20 degrees low and sent three planes back to the gate, has anyone else seen these newer Honeywell probes drift like that after just 600 flight hours?
That "20 degrees low" figure is the part that gets me, because a slow drift like that will not trip a lot of the older comparators until it is way out of spec. If they are really wandering that much at 600 hours, the problem is probably in how they are built and not just one bad batch. We started pulling and bench checking ours at every A check and that caught two more before they ever made it to the gate.