B757/767 TAT probe overheating
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B757/767 TAT probe overheating
Wondering whether anyone has experienced an insidious un-announced TAT probe overheat?
I once flew a 757 that pilots claimed not to be able to reach normal CRZ levels. I realized that TAT was unusually high to what was expected, so I talked to a traffic just ahead at same level. He reported a TAT some 20c less. We had no TAT probe warning, since that only applies for probe heat inop; ours was exactly the opposite.
A false, let's say, ISA+30 data supplied to the air data computer corrupts true Mach number, OAT, engine thrust limits, FMC OPT & STEP TO levels, and even computed X-wind.
Now, I learned that at least on some 767s, Boeing has installed a second TAT probe.
Our 757s had only one on the RH side.
Note: A TAT probe change by MX solved the unannounced problem.
I once flew a 757 that pilots claimed not to be able to reach normal CRZ levels. I realized that TAT was unusually high to what was expected, so I talked to a traffic just ahead at same level. He reported a TAT some 20c less. We had no TAT probe warning, since that only applies for probe heat inop; ours was exactly the opposite.
A false, let's say, ISA+30 data supplied to the air data computer corrupts true Mach number, OAT, engine thrust limits, FMC OPT & STEP TO levels, and even computed X-wind.
Now, I learned that at least on some 767s, Boeing has installed a second TAT probe.
Our 757s had only one on the RH side.
Note: A TAT probe change by MX solved the unannounced problem.
