Required vertical speed from a gradient
A fictional departure-planning worksheet supplies a climb gradient requirement of 4.5 percent and a groundspeed of 160 knots. It defines one nautical mile as 6076 feet for this calculation and asks for the corresponding vertical speed. A learner multiplies 4.5 by 160 but treats the answer as metres per second. Another finds approximately 730 feet per minute and claims that the aeroplane must therefore be capable of meeting the departure. The task asks for the dimensional calculation and the distinction between a requirement and demonstrated capability. No actual aircraft performance chart, temperature, mass, engine condition or obstacle procedure is provided. The calculation is a classroom model only and does not authorize attempting a departure. A suitable answer shows horizontal distance per minute, applies the gradient and states what further evidence would be needed.
1. Calculate the required vertical speed.
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At 160 nautical miles per hour, horizontal speed is 160×6076/60 feet per minute. Multiplying by 0.045 gives approximately 729 feet per minute, conventionally rounded to 730.
2. Does this prove the aircraft can meet the requirement?
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No. It calculates the requirement at the stated groundspeed. Actual approved aircraft performance under the relevant conditions and the complete procedure must be assessed separately.