T-28 measurements: Air temperature
Temperature
is available from two sensors, mounted under the left wing. The fundamental sensing element in each probe
is a platinum resistance element. The
de-iced Rosemount sensor (data tag 106 in the Recorded and Derived Parameter
List) is more stable and more accurate in dry air and in light icing
conditions. It has a response time of
approximately one second. The
reverse-flow temperature sensor (data tag107) is designed to provide a measure
of temperature unaffected by wetting in clouds or icing, even in heavy icing
conditions.
It
has a response time of approximately four seconds. Its response is more sensitive to variations
in angle-of-attack, and to changes in airflow due to icing, than is the
response of the Rosemount sensor.
However, relative variations in temperature from one region to another
in moderate to heavy icing regions are better judged using the reverse-flow
sensor (Lawson and Cooper, 1990). Figure 1 shows an example of the recorded temperature with the two
sensors.
Figure 1. Rosemount and Reverse Flow
temperature measurements during Flight 781 (