PHAK Chapter 11 Notes

Introduction

• Discusses factors affecting aircraft performance:
  • Aircraft weight
  • Atmospheric conditions
  • Runway environment
  • Physical laws governing forces on an aircraft

Importance of Performance Data

• AFM/POH contains essential operating data:
  • Takeoff, climb, range, endurance, descent, landing
• Understanding performance data is crucial for safe operations.

Atmospheric Pressure

• Pilots focus on atmospheric pressure for:
  • Weather changes
  • Aircraft lift
  • Flight instruments functionality (altimeter, ASI, VSI, manifold pressure gauge)

Standard Atmospheric Conditions

• Standard sea level pressure: 14.7 psi,
  • 29.92"Hg or 1013 mb
• Temperature lapse rate: 3.5°F or 2°C per 1,000 ft up to 36,000 ft
• Pressure lapse rate: 1"Hg per 1,000 ft up to 10,000 ft

Pressure and Density Altitude

• Pressure Altitude: Height above the standard datum plane (29.92"Hg)
• Density Altitude: Pressure altitude corrected for nonstandard temperature

Effects on Performance

• Low air density reduces:
  • Power
  • Thrust
  • Lift

Performance

• Describes aircraft abilities:
  • Takeoff/landing distance, climb rate, ceiling, range, speed, stability, fuel economy

Flight Dynamics

• Equilibrium required for steady flight
• Maximum level flight speed when thrust equals maximum available power

Climb Performance

• Positive climb:
  1. Excess power used
  2. Kinetic energy converted to potential energy
• Angle of Climb (AOC): Max altitude gain with minimum ground distance
• Rate of Climb (ROC): Max altitude gain over time

Climb Performance Factors

• Weight, altitude, and configuration affect excess thrust and power
• Climb performance diminishes with altitude

Takeoff and Landing Performance

• Influenced by:
  • Weight
  • Wind
  • Runway conditions (surface, gradient)

Takeoff Considerations

• Increased weight requires higher lift-off speed
• Wind affects ground speed needed for liftoff

Landing Considerations

• Minimum landing distance requires efficient deceleration
• Increased landing weight increases speed and distance

Performance Charts

• Provided in AFM/POH for predicting aircraft performance
• Include takeoff, climb, cruise, and landing data
• Charts vary in format (tables, graphs)

Using Charts

• Accurate reading is crucial
• Account for specific conditions

Chapter Summary

• Performance varies among aircraft
• Reliance on computerized flight planning systems
• Importance of understanding performance characteristics, capabilities, and planning programs