I am not convinced that all of the Pitots froze up, the likely hood of all three probes sufferring the same fault at the same time would be so incredibly unlikey. This would only happen if none of them had probe heat on.
This is not to say one did not fail, and the crew simple screwed up the fault isloation procedure.
But a simple pitot issue should not have cause a bunch of the other failures such as the ISIS failure or TCAS failure.
Pitot tubes are from my experience inherently reliable devices, i have only every changed 2 in my 15 years in aviation maintenance. The rest were for modification reasons about 4 years back.
The most rescent, as i have previously said was a partial failure of the heating element so it was getting warm but not hot.
This probe was quarantined and sent back to the manufaturer who did dismantled it and discovered the heater element to have shorted against the probe, which would have normally burnt the element out, but in this case there must have been just enough resistance to keep the element current down. Which is why it was not getting hot enough.
A one off defect, though they did create a report on if and our my airline created an information bulletin for both Maintenance and Aircrew to read. This was mostly because the probe had had this defect for a number of weeks and only froze in very specific conditions, and difficult to prove on the ground in testing.
When testing it i found it was warming up which would have misled the previous guys testing it. But i took it a step further and compared it with the others and only then could you see a clear difference in the heating.
For info this was on a Boeing.
I wonder what happens if you turn off all the ADIRUs? can you turn off the ISIS?
Also on the FDR and CVR, they are positioned in the tail, and could easily be ejectable. A few issues though. The aircraft needs to identify it is crashing. On what basis does it make this assumption? The last thing you want is these things to be ejected everytime some one almost crashes, which probably happens way more than people actualy crash.
i could just imagine it.
"Man killed as Data Recorder falls from the sky as Hero pilot saves the lives of hundreds"
But in terms of and automated data transmission of FDR could easily be done. But again based on what assumptions. How often has a normal landing turned into a crash in mear seconds?
This is not to say one did not fail, and the crew simple screwed up the fault isloation procedure.
But a simple pitot issue should not have cause a bunch of the other failures such as the ISIS failure or TCAS failure.
Pitot tubes are from my experience inherently reliable devices, i have only every changed 2 in my 15 years in aviation maintenance. The rest were for modification reasons about 4 years back.
The most rescent, as i have previously said was a partial failure of the heating element so it was getting warm but not hot.
This probe was quarantined and sent back to the manufaturer who did dismantled it and discovered the heater element to have shorted against the probe, which would have normally burnt the element out, but in this case there must have been just enough resistance to keep the element current down. Which is why it was not getting hot enough.
A one off defect, though they did create a report on if and our my airline created an information bulletin for both Maintenance and Aircrew to read. This was mostly because the probe had had this defect for a number of weeks and only froze in very specific conditions, and difficult to prove on the ground in testing.
When testing it i found it was warming up which would have misled the previous guys testing it. But i took it a step further and compared it with the others and only then could you see a clear difference in the heating.
For info this was on a Boeing.
I wonder what happens if you turn off all the ADIRUs? can you turn off the ISIS?
Also on the FDR and CVR, they are positioned in the tail, and could easily be ejectable. A few issues though. The aircraft needs to identify it is crashing. On what basis does it make this assumption? The last thing you want is these things to be ejected everytime some one almost crashes, which probably happens way more than people actualy crash.
i could just imagine it.
"Man killed as Data Recorder falls from the sky as Hero pilot saves the lives of hundreds"
But in terms of and automated data transmission of FDR could easily be done. But again based on what assumptions. How often has a normal landing turned into a crash in mear seconds?
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