On the ground, the TO dataset must be ALL when OAT is less than 5°C and which conditions apply?

On the ground, the TO dataset must be ALL when OAT is less than 5°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 temperatures are below 5°C, cold-weather takeoff performance on the ground becomes more sensitive to icing and ingestion hazards. The ALL takeoff data set is used to cover those worst-case conditions. Visible moisture within 1,700 feet AFE means there could be icing potential on the surfaces or in the engines right up to the takeoff area, which can change required thrust and acceleration. Additionally, surface conditions on ramps, taxiways, or runways—such as snow, ice, standing water, or slush—that could be ingested by engines or freeze on engine nacelles or sensor probes create further performance and sensor-reading safety concerns. Since either condition can affect takeoff performance in the cold, using the ALL dataset is needed when OAT is under 5°C and these hazards may be present.

When temperatures are below 5°C, cold-weather takeoff performance on the ground becomes more sensitive to icing and ingestion hazards. The ALL takeoff data set is used to cover those worst-case conditions. Visible moisture within 1,700 feet AFE means there could be icing potential on the surfaces or in the engines right up to the takeoff area, which can change required thrust and acceleration. Additionally, surface conditions on ramps, taxiways, or runways—such as snow, ice, standing water, or slush—that could be ingested by engines or freeze on engine nacelles or sensor probes create further performance and sensor-reading safety concerns. Since either condition can affect takeoff performance in the cold, using the ALL dataset is needed when OAT is under 5°C and these hazards may be present.