During instrument departure planning, which gradient is assumed for all engines operating?

• A. 3.3%
• B. 2.4% with all engines operating and 1.5% with one engine inoperative
• C. 5% with all engines operating and a climb gradient margin respectively of 0.8%, 0.9%, 1% with two, three and four engines
• D. 2.4% with two engines, 2.7% with three engines, 3% with four engines

Answer: (A)

In instrument departure planning you use a climb gradient to guarantee obstacle clearance as you begin the climb after takeoff. For the baseline case where all engines are operating, the standard assumed climb gradient is 3.3%, which is about 200 feet per nautical mile. This provides a consistent, conservative target for planning the SID and ensures you have enough altitude gain within the available distance to clear obstacles or terrain near the airport.

If an engine fails, the required gradient becomes higher to maintain clearance, which is why other options show different values tied to engine-out scenarios or extra margins. So the 3.3% figure is the standard baseline for all-engines-operating departures. As a quick check, 3.3% equals roughly 200 ft per NM, so planning to reach a given altitude will require about that many nautical miles of distance.