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Temperature Datum (TD) switches aft of Condition Levers
AUTO (Normal Position): Powers temperature datum system, allowing start limiting,
temperature limiting, and temperature controlling modes.
LKD (locked): May be used when the throttles are in the temperature controlling range (above
65º throttle lever angle)
and
TD correction lights extinguished to “lock in” the existing
correction. If an over temperature condition is sensed, the TD system will respond by unlocking
the existing fuel correction and reducing fuel flow. The locked position is functional only if the
TD system is in the temperature controlling range
and
TD correction lights extinguished. If LKD
is selected with the throttles below the temperature controlling range or with the
TD correction
lights illuminated, the TD fuel valves are placed in the fixed, nominal bypass position.
NULL: Electrical power removed from TD system, and all fuel valves placed in fixed, nominal
bypass position. No overtemperature protection is provided.