On the ground, the TO dataset must be ENG when OAT is between 5°C and 10°C and which conditions apply?

On the ground, the TO dataset must be ENG when OAT is between 5°C and 10°C and which conditions apply?

• A. Visible moisture up to 1,700 ft AFE
• B. When operating on ramps, taxiways, runways where surface snow, ice, standing water, or slush may be ingested by the engines or freeze on engines, nacelles, or engine sensor probes
• C. Both of the above
• D. Neither of the above

Answer: (C)

When the OAT is between 5°C and 10°C, the takeoff dataset must be the engine dataset if conditions on the ground could affect engine ingestion or sensor readings. Visible moisture up to 1,700 ft AFE indicates there could be icing risks near the surface, since moisture in this temperature range can freeze and influence engine performance or nacelle/sensor icing. Likewise, operating on ramps, taxiways, or runways where surface snow, ice, standing water, or slush may be ingested by the engines or freeze on engines, nacelles, or engine sensor probes creates a real risk to engine operation and instrumentation. Because either scenario can impact takeoff performance, both conditions require using the ENG takeoff dataset. The option listing only one of the conditions would miss the other risk, and neither condition alone covers all the factors involved.

When the OAT is between 5°C and 10°C, the takeoff dataset must be the engine dataset if conditions on the ground could affect engine ingestion or sensor readings. Visible moisture up to 1,700 ft AFE indicates there could be icing risks near the surface, since moisture in this temperature range can freeze and influence engine performance or nacelle/sensor icing. Likewise, operating on ramps, taxiways, or runways where surface snow, ice, standing water, or slush may be ingested by the engines or freeze on engines, nacelles, or engine sensor probes creates a real risk to engine operation and instrumentation. Because either scenario can impact takeoff performance, both conditions require using the ENG takeoff dataset. The option listing only one of the conditions would miss the other risk, and neither condition alone covers all the factors involved.