Originally Posted by

**Evan**
Secondly, I'm not following his math. By the above reasoning, climbing out of FL35 for FL37 at SALPU, there would be 2.4t of route reserve providing 20 minutes of diversion available without a fuel stopover (with seems adequate to me). That works out to an average burn rate at cruise of 120kg/min: 2,400/20=120. Then he states that if the flight maintained FL35 after SALPU instead of climbing as planned, the route reserve would only allow for an 8 minute diversion after SALPU. The average burn rate at cruise is now 112.5kg/min: 900/8=112.5. That doesn't add up in my head. Why is the burn rate lower at the lower FL, when it should be higher?