4.7 Descent

Objective 
 To conduct a controlled and passenger-comfort-oriented descent from cruise altitude to approach phase while maintaining compliance with all constraints. 
 
 Descent Philosophy (VA Standard) 
 The descent is primarily flown with a focus on: 
 
 Passenger comfort (smooth vertical profile) 
 Pilot control over vertical path 
 Compliance with ATC and charted constraints 
 
 
 Descent Preparation 
 PF: 
 
 Reviews arrival (STAR, constraints, transition) 
 Conducts approach briefing 
 
 PM: 
 
 Programs arrival and approach into MCDU 
 Verifies constraints and routing 
 
 
 Top of Descent (TOD) 
 
 Descent initiated prior to or at TOD 
 ATC clearance must be received before descent 
 
 
 Descent Mode (STANDARD VA PROCEDURE) 
 Vertical Mode: 
 
 Primary Mode → SELECTED V/S (Vertical Speed) 
 
 The descent is manually controlled to ensure: 
 
 Smooth cabin experience 
 Stable and predictable vertical profile 
 
 
 Managed Mode Usage: 
 
 Managed Descent is NOT the default 
 It is used only when required to comply with constraints 
 
 Examples: 
 
 Altitude restrictions on STAR 
 Complex vertical profiles 
 When automation assistance is beneficial 
 
 
 Speed Management 
 
 Speed Mode → MANAGED (throughout STAR) 
 
 The aircraft shall: 
 
 Follow FMGS speed profile 
 Respect all published constraints 
 
 
 After STAR (Approach Phase Transition) 
 
 Speed may be adjusted as required:
 
 ATC instructions 
 Approach setup 
 Traffic situation 
 
 
 
 
 Exceptions 
 Selected modes may be used if: 
 
 ATC assigns specific: 
 
 Speed 
 Descent rate 
 Altitude constraints 
 
 
 Abnormal situations occur 
 
 
 Monitoring (PM) 
 
 Vertical path vs constraints 
 Speed profile 
 ATC compliance 
 Energy state (too high / too fast) 
 
 
 Energy Management 
 If aircraft is high or fast: 
 
 Increase descent rate (V/S adjustment) 
 Use Speed Brakes as required 
 
 
 Thrust Management 
 
 Typically idle during descent 
 Monitor engine parameters 
 
 
 Transition Level 
 
 Set local QNH when passing transition level 
 
 
 Key Principles 
 
 Smooth descent is priority 
 Maintain control over vertical profile 
 Use automation selectively, not blindly 
 
 
 Core Rule 
 “Vertical path is pilot-controlled – speed is aircraft-managed.” 
 
 Outcome 
 A properly managed descent results in: 
 
 Passenger comfort 
 Stabilized approach conditions 
 Reduced workload in final phase