For MIL operating conditions, which distance pair applies?

• A. Intake 9 ft; Exhaust 115-155 ft
• B. Intake 9 ft; Exhaust 325-725 ft
• C. Intake 25 ft; Exhaust 325-725 ft
• D. Intake 25 ft; Exhaust 850-925 ft

Answer: (C)

Safe engine operation on the ground requires keeping the intake away from heat, debris, and exhaust plumes while giving the exhaust enough distance to disperse and not recirculate back into the intake. The intake needs only a modest clearance, about 25 ft, to avoid ingesting debris or drawing in heated air too close to support equipment. The exhaust, on the other hand, must be far enough away to ensure the plume doesn’t flow back toward the intake or heat nearby areas, with a dispersion range that accounts for wind and other conditions. The pairing of 25 ft for the intake and 325–725 ft for the exhaust provides this practical balance, aligning with MIL operating guidelines. Distances that place the intake only 9 ft away or exhaust distances outside the 325–725 ft window don’t meet these separation needs and aren’t considered safe or standard.