Introduction 

Modified Reserves 

This topic will focus on the specific functionality of modified reserves, and how that fuel saving measure can be employed during practical flight planning. 

We estimate that this will take 3 minutes to complete.

Detailed Explanation 

Modified Reserve Functionality

This module demonstrates the function and benefits of Modified Reserves. To highlight the fuel savings we will begin with an already computed flight, note the fuel requirement for that flight, and then show the difference with Modified Reserves.

Modified Reserves allow for reduction in required fuel for international flights, in accordance with fuel saving authorizations similar to FAA Operations Specification B043.

Note that the original flight plan requires 5,834lbs / 30min of Holding Fuel, and 5,999lbs / 31min of Reserve Fuel.

Click the Reserve green arrow button.

Click the Policy dropdown button.

Click the Policy (Modified Reserves) list item.

Click the Compute button.

With Modified Reserves, the fuel requirements are 0lbs / 0min Holding Fuel, and 8,655 / 45min Reserve Fuel.

This is a savings of 3,178lbs / 16min of fuel.

Click the Fuel >> expansion button.

The original intent of the Modified Reserves, was to meet the requirements of fuel saving authorization, similar to FAA Operations Specification B043.  As such, when Modified Reserves are used, the system eliminates Holding Fuel, and changes the Reserve to a static 45min of fuel.

Another aspect of this function is the ability to specify sections of the route which transit Class II Airspace.  The FAA OpSpec B043 requires fuel for "10 percent of that portion of the enroute time (between the departure airport and the airport to which it was released) where the aircraft's position cannot be "reliably fixed" at least once each hour."

To achieve this, the system allows you to enter waypoint pairs for the Class II segments.

Click the Mod Resv dropdown button.

Click the SMR list item.

Note the description below, indicating the first modified reserve waypoint. 

Click the Second Mod Resv dropdown button.

Click the NOMIN list item.

Click the Compute button.

With the addition of the Modified Reserve Waypoints, simulating Class II Airspace, the fuel requirement is now 9,227lbs / 48min of Reserve Fuel.