6. MCDU / FMS Guide

6.1 Objective
The MCDU (Multipurpose Control and Display Unit) is used to manage: 
 
 Flight planning 
 Navigation 
 Performance calculations 
 Aircraft guidance 
 
 Correct setup is essential for safe and efficient flight operations. 
 
 General Philosophy 
 
 The FMGS manages the flight only if correctly programmed 
 Pilots must always verify inputs 
 Never rely blindly on automation

6.2 INIT A Page
Used for basic flight initialization. 
 Required Entries: 
 
 FROM / TO → Departure & Destination 
 FLT NBR → Flight Number 
 COST INDEX → Airline value 
 CRZ FL → Planned cruise level 
 
 
 Key Rule 
 All entries must be cross-checked by PM

6.3 Flight Plan Page
Route Input: 
 
 Insert waypoints / airways 
 Select SID and runway 
 Insert STAR and approach 
 
 
 Important: 
 
 Remove all discontinuities 
 Verify route against briefing 
 Check for incorrect turns 
 
 
 Core Rule 
 “No discontinuities without reason.”

6.4 INIT B Page
Fuel & Weight: 
 
 Block Fuel → INSERT 
 Zero Fuel Weight → INSERT 
 
 
 Importance: 
 Incorrect values will result in: 
 
 Wrong fuel prediction 
 Incorrect performance

6.5 Performance Pages
Takeoff (PERF TO) 
 
 V1 / VR / V2 → INSERT 
 FLEX Temperature → SET 
 Thrust Reduction Altitude → SET 
 Acceleration Altitude → SET 
 
 
 Climb (PERF CLB) 
 
 Managed speed profile active 
 Monitor climb performance 
 
 
 Cruise (PERF CRZ) 
 
 Mach mode active 
 Fuel predictions monitored 
 
 
 Descent (PERF DES) 
 
 Managed descent profile available 
 Used mainly for constraints 
 
 
 Approach (PERF APPR) 
 
 VAPP → CHECK / INSERT 
 Wind → INSERT 
 Minimums → SET

6.6 Key Pilot Tasks and common errors
Key Pilot Tasks 
 During all phases: 
 
 Monitor flight plan 
 Check for route deviations 
 Verify altitude and speed constraints 
 
 
 Common Errors 
 
 Missing discontinuities 
 Incorrect SID/STAR selection 
 Wrong performance data 
 Not updating approach

6.7 Crosscheck Concept
Every critical input must be: 
 
 Entered by PF 
 Verified by PM 
 
 
 Core Rule 
 “Garbage in → Garbage out.” 
 
 Key Principle 
 The MCDU is a tool: 
 
 It supports the pilot 
 It does not replace decision-making 
 
 
 Outcome 
 A correctly programmed MCDU ensures: 
 
 Accurate navigation 
 Efficient flight profile 
 Reduced workload