DIFRIPPS: A STRUCTURED PREPARATION AND REVIEW
DIFRIPPS is a memory aid for our route through the MCDU pages: Data, Init A, Flight Plan, Rad Nav, Init B, Progress, Performance and Secondary Flight Plan. Say it once or twice. The unusual name has already done some of the remembering for us. For the first few flights, keep the expanded version beside the keyboard. It gives each part of the preparation a place to live. [45, Unpaginated, single paragraph]
Think of the sequence as a review route. Data checks the aircraft and navigation information. Init A establishes the flight's identity. Flight Plan builds the route, and Rad Nav reviews the radio aids. Init B supplies mass and fuel information. Progress lets us inspect the developing picture; Performance prepares the takeoff data. The secondary plan holds an alternative. We will explain each page before its practical exercise, so the letters will gradually acquire familiar jobs. [45, Unpaginated, single paragraph]
For the actual page functions, we use the identified FM Pilot's Guide together with the relevant Fenix documentation. That distinction is useful when following any tutorial. Learn the reason for an action and then check how the loaded aircraft implements it. The exercises here keep the familiar order while using the audited Fenix preparation and database workflow. [46, Spoken explanation of DIFRIPPS and MCDU preparation] [46, Spoken explanation of the secondary flight-plan concept] [26, PDF pp. 99-128]
Some information is ready earlier than other information. We can prepare the route while the aircraft is still being loaded, but final mass and takeoff calculations need the final loading information. It helps to make two purposeful passes: establish the navigation picture, then finish the weight-dependent preparation when its inputs are ready. There is no prize for filling every field first and correcting it all afterwards. [19, PDF pp. 6-8]
An import or a later change brings us back to the relevant checks. If the runway changes, revisit the route and performance preparation. If a revised loadsheet changes the mass, return to the affected entries and calculation. DIFRIPPS helps us remember those connections. With practice the review becomes quicker, while the useful part remains: every important item has received attention at the point when it can be checked properly. [19, PDF pp. 6-8]
The supplied DIFRIPPS sequence, expanded into the actual page names and review task. [45, Unpaginated, single paragraph]
IN PRACTICE: Use DIFRIPPS as two working passes
Before you begin: The MCDU is available and the flight identity is known. Loading may still be in progress; final performance work must wait for its actual inputs.
1. Confirm the order you will use
Action. Follow Data, Init A, Flight Plan, Rad Nav, Init B, Progress, Performance and Secondary Flight Plan. Use this as a personal review route through the pages, not as permission to skip the aircraft checklist.
Check. You have a repeatable order and can return to a specific incomplete item after an interruption. [45, Unpaginated, single paragraph] [46, Spoken explanation of DIFRIPPS and MCDU preparation]
2. Finish the navigation inputs first
Action. Settle the active navigation database, flight identity and intended route. Review radio-navigation selections that belong to the departure or anticipated arrival. Mark any item still awaiting a clearance.
Check. The route has a clear origin, destination and reason for each selected procedure. An assumption is visibly separate from a clearance. [19, PDF pp. 6-8] [26, PDF pp. 99-128]
3. Keep final loading work together
Action. When loading is final, revisit INIT B and compare the accepted mass and fuel entries with the aircraft and latest loadsheet. Then review PROG and complete the takeoff-performance work.
Check. The performance calculation uses the same aircraft, load and runway assumptions as the final preparation. [26, PDF p. 123] [26, PDF pp. 125-128]
4. Build the spare from a checked route
Action. Prepare the secondary plan after the active plan has been reviewed. Decide what the spare is for: a genuine runway-change option or a separately prepared return, rather than a second unexamined copy.
Check. The secondary plan has a specific purpose and does not conceal an unresolved error in the active plan. [26, PDF p. 121] [26, PDF pp. 432-435]
5. Close the loop on a change
Action. After a runway, loading or route change, return to the pages it affects. Recheck the route, weights, takeoff calculation and secondary plan as applicable; do not simply resume at the next letter.
Check. The preparation is internally consistent again, including entries made earlier in the session. [26, PDF pp. 142-165] [26, PDF p. 128]
Complete when: Each page has a defined job. Navigation preparation is coherent, while weight-dependent entries remain open until the final information is available.