FAA Aircraft Dispatcher (ADX)Flight Planning and PerformanceMedium
A dispatcher plans a long-range flight using a 'step climb' profile rather than a single cruise altitude. What is the primary purpose of this technique?
- ATo comply with hemispheric cruising altitude rules
- BTo climb to progressively higher altitudes as weight decreases, maintaining optimum cruise efficiency
- CTo reduce the total flight time by flying faster true airspeeds
- DTo avoid turbulence reported at lower altitudes
Show answer & explanationAnswer & explanation
Correct answer: B. To climb to progressively higher altitudes as weight decreases, maintaining optimum cruise efficiency
As fuel burns off during cruise, aircraft weight decreases, and the optimum (most fuel-efficient) cruise altitude increases. A step climb allows the aircraft to periodically climb to a higher altitude, staying near the optimum altitude for its current weight and improving specific range/fuel efficiency over the flight.
Why the other options are wrong
- A. Hemispheric rules govern altitude selection by direction, not the step climb technique itself.
- C. Step climbs are about fuel efficiency at optimum altitude, not simply higher TAS.
- D. Turbulence avoidance is not the defining purpose of a step climb.
Step Climb
A step climb is a planned climb to a higher cruise altitude during flight, performed as aircraft weight decreases, to maintain proximity to the optimum altitude for fuel efficiency.
- Optimum altitude rises as weight decreases
- Requires ATC coordination/clearance
- Improves specific range over long flights
Memory trick: 'Lighter plane, higher lane' — climb steps track decreasing weight.