Air Data System

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• Air Data System
• Total Air Temperature Probe
• Use of NCEP Warm Bias Data
• Presented by David Cole

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BUG
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Air Data System
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Air Data System
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AIR DATA MODULE
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TAT PROBE
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TAT FUNCTION
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(No Transcript)
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TOTAL AIR TEMPERATURE

• ?tw Total air temperature error correction due
  to resistance of the nominal length of wiring
  between the probe and the air data computer
  (degrees).
• TTi Indicated total air temperature - the total
  air temperature as measured at the input
  terminals of the air data computer (degrees
  absolute).

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TOTAL AIR TEMPERATURE/STATIC AIR TEMPERATURE

• TT Total air temperature - indicated total air
  temperature corrected for wiring resistance and
  recovery error (degrees absolute) the air data
  computer output in degrees C.
• Ts Static air temperature - total air
  temperature corrected for the adiabatic
  temperature rise due to compressibility (degrees
  absolute) the air data computer output in
  degrees C.

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FORMULAS

• TOTAL AIR TEMPERATURE
• TT Indicated Total Air Temp Total Air Temp
  Error Corr. Due to Wire Resistance
• 1- 0.2 Computer Mach Number Squared
• STATIC AIR TEMPERATURE
• TS Total Air Temp
• 1 0.2 Computer Mach Number Squared

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TAT TEMPERATURE CURVE
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TAT/ADIRU FUNCTION
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TAT PROBE ANALYSIS
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TAT PROBE REVIEW

• NCEP DATA ALLOWS CAL TO ISOLATE TAT PROBES THAT
  HAVE A HIGHER THAN NORMAL TEMPERATURE READING
• ISOLATION OF THESE PROBES ALLOWS CAL TO REPLACE
  THEM PRIOR TO A POSSIBLE FAILURE
• CAL AND BOEING ARE IN THE PROCESS OF IDENTIFYING
  HOW A HIGHER THAN NORMAL TAT PROBE TEMPERATURE
  CAN ALTER FUEL MILEAGE