Landing Phase of Flight
Importance of Calculating Landing Distance
- Essential to have adequate runway to stop aircraft safely.
- Avoid overrunning into fields, sea, or buildings.
Landing Distance Components
- Starts from "screen height" (50 feet for class A, 35 feet for class B) to complete stop on runway.
- Consists of both an airborne and ground run section.
Screen Height
- Imaginary wall at runway threshold; aircraft must clear this height.
- Thresholds can be displaced, affecting landing calculations.
Landing Speed: Vref
- Vref is the reference speed for landing.
- Calculated by comparing:
- Minimum control speed for landing (Vmcl).
- Stall speed in landing configuration (Vso) factored by 1.3 for safety.
- Importance of flying at Vref to maintain control and avoid stalling.
Braking and Deceleration
- Braking: Converts kinetic energy to heat, may require cooldown on hot days.
- Ground Spoilers: Reduce lift to transfer full weight onto wheels for effective braking.
- Anti-Skid: Prevents tire skidding by intermittently applying brakes.
- Auto-Brake System: Automates braking shortly after touchdown.
- Reverse Thrust: Used to assist with braking; varies by airline policy for cost-effectiveness.
Factors Affecting Landing Distance
- Weight: Heavier aircraft need higher speed for lift, increasing landing distance.
- Altitude and Temperature: Lower air density requires higher speed.
- **Wind:
- Headwind reduces ground speed, lowering landing distance.
- Tailwind increases ground speed, requiring more landing distance.
Runway and Surface Conditions
- Best conditions: dry tarmac with high friction.
- Wet conditions increase landing distance by 15%.
- Slope of runway has minor effects; upslopes help, downslopes hinder.
Safety Margins
- Variability in human control requires safety factors:
- Jets: Use 60% of runway.
- Propellers: Use 70% of runway.
- Calculations ensure landing distance available exceeds required distance with safety margins.
These notes provide a summary of the key elements of the landing phase of flight, focusing on the calculation and factors affecting landing distance as well as the technologies used to ensure safe deceleration of aircraft. The importance of speed management and adherence to Vref is emphasized, along with considerations for runway and weather conditions.