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PilotSchool Knowledge Base

Using Performance Charts for Flight Scenarios

Learning Outcomes

Upon completion of this section, you should be able to:

  • Extract take-off parameters including take-off safety speed, flap setting, and power from performance charts.
  • Extract landing parameters such as threshold speed and flap setting.
  • Determine the take-off distance required (TODR).
  • Assess maximum landing weight and landing distance required (LDR).
  • Evaluate climb weight limit and maximum take-off weight.
  • Understand the conditions that affect power, flap setting, take-off safety speed, and threshold speed parameters.

Introduction

Understanding the performance characteristics of an aircraft during take-off and landing is crucial for safe and efficient flight operations. This section provides a comprehensive guide on how to use performance charts to extract critical parameters and understand the conditions affecting them.

Take-off Parameters

Take-off Safety Speed (V2)

Take-off safety speed is the speed at which an aircraft can safely continue the takeoff during an engine failure. This speed depends on several factors, including weight, air density, and flap settings. It is derived from the aircraft’s performance charts, typically located in the Aircraft Flight Manual (AFM) or Pilot’s Operating Handbook (POH).

Flap Setting

Flaps are used to increase lift at lower speeds and are crucial for optimizing take-off performance. The recommended flap settings can be determined from the performance charts based on the aircraft weight and environmental conditions.

Power Settings

Power settings for take-off are influenced by atmosphere density and weight. Typically, full power is used for take-off to achieve maximum thrust, which is represented as maximum take-off power settings in the performance charts.

Landing Parameters

Threshold Speed (Vref)

Threshold speed, also known as reference landing speed, is critical for determining the safe approach and landing speeds. This speed can be found on landing performance charts and varies with weight and configuration.

Flap Setting

For landing, flap settings are adjusted to reduce speed and increase descent angle while maintaining lift. Correct settings are crucial to achieving optimal landing performance and are specified in the aircraft’s landing performance charts.

Calculating TODR and LDR

Take-off Distance Required (TODR)

To calculate TODR, performance charts must be consulted:

  1. Determine Density Altitude: Calculate using pressure altitude and temperature.
  2. Adjust for Weight: Traverse performance lines to the correct weight.
  3. Compensate for Wind and Slope: Use horizontal adjustments for wind and slope impact.
  4. Read the TODR Value: This is the point on the chart corresponding to the conditions.

Landing Distance Required (LDR)

The process for determining LDR is similar to TODR:

  1. Calculate Density Altitude: Combine pressure altitude with current temperature.
  2. Adjust for Weight and Surface: Plot these lines on the landing performance chart.
  3. Compensate for Wind: Make appropriate adjustments based on wind conditions.
  4. Extract LDR Value: Based on chart readings under these combined influences.

Maximum Weights and Climb Performance

Maximum Landing Weight

Determine from performance charts considering operational limits of the landing gear and structural capacity.

Climb Weight Limit

Weight is a crucial factor affecting climb performance. The climb weight limit ensures sufficient thrust for safe climbing within allowable structural and safety margins.

Maximum Take-off Weight (MTOW)

Maximum take-off weight is set to ensure that the aircraft can safely operate within structural capabilities and performance margins, including climb-out after take-off.

Conditions Affecting Performance Parameters

Atmospheric Pressure and Air Density

Density altitude calculations affect power, thrust, and lift, thereby impacting the take-off safety speed and threshold speed. Lower density decreases performance, requiring adjustments as indicated in the AFM/POH charts.

Weight and Balance

Increases in aircraft weight directly influence stall speeds and required power, affecting both take-off and landing performance parameters. Load distribution also impacts stability and control.

Surface, Wind, and Ground Effect

Surface conditions (e.g., paved vs unpaved), wind (headwind or tailwind), and ground effect all necessitate adjustments in performance charts during both take-off and landing planning.

References

By understanding and applying these factors and procedures, pilots can enhance their decision-making process for optimal and safe aircraft operation during the critical phases of take-off and landing.