A propulsion engine, using the speed control circuit shown in the illustration, fails to function at speeds lower than the low end of the critical speed range. Which of the following statements describes what should be done to correct this malfunction? Illustration MO-0114

Correct Answer: Option B — Device 17A needs to be replaced, repaired, or reset to the set point coinciding with the RPM value for the low end of the critical speed range.

Device 17A establishes the lower boundary of the critical speed range. When a propulsion engine fails below this speed, 17A must be repaired, replaced, or reset to accurately match the specific RPM threshold.