In the 0 C to -16 C range, after inner zones heat for 45 seconds, what is the next step in the Propeller De-Ice sequence?

• A. Outer zones heat for 45 seconds, then off for 90 seconds
• B. Outer zones heat, then off for 90 seconds
• C. All zones heat for 90 seconds
• D. System turns off immediately

Answer: (B)

In this temperature range, the propeller de-ice system uses a staged heating pattern. After the inner zones have heated for 45 seconds to begin breaking up the ice, the next step is to heat the outer zones to extend the de-icing effect across the entire blade area. Following that, the system goes off for about 90 seconds to allow the heat to do its work and to prevent overheating. So, the next step is outer zones heating, then a 90-second rest. This sequencing avoids heating all zones at once and ensures a proper rest interval between cycles.