# Flight Path Angle: Definition & Effect on Airplane

• amirshah
In summary, angle of attack is a factor in performance as the aircraft is either gaining or losing potential energy. Flight path angle is a factor in performance because the aircraft is either gaining or losing potential energy and it is similar to cycling up or down a hill.

#### amirshah

Hello,

What is flight path angle and how does it affect an airplane? What is the difference between flight path angle (glide angle or climb angle) and angle of attack? When the flight path angle is changed during flight, does the angle of attack also changed? I found that lift is always rely on angle of attack only but from aircraft performance discussion I have seen lift also changed with the variation of flight path angle (L = W cos*gamma). Could you explain what does that mean? I reaaly confused with these two angles.

Thanks. At least, I have known the relationship between angle of attack and pitch angle. How's about angle of attack and flight path angle. In the equations of motion especially in flight performance, flight path angle directly affect the performance calculation.

Flight path angle is a factor in performance because the aircraft is either gaining or losing potential energy (for an angle other than zero). It is similar to cycling up or down a hill. In still air the climb rate is determined by how much engine power is available over and above simply keeping the aircraft in level flight.

There is not a fixed relationship between AOA and flight path. I have been in strong thermals with the nose pushed over at a low angle of attack and a high airspeed, still gaining altitude. The positive flight path angle in a case like that is mostly due to the moving airmass rather than engine power.

Conversely there is a maneuver call slow flight in which the AOA is nearly max at low airspeed in level flight.

Hope this helps.

## What is flight path angle?

Flight path angle is the angle between the flight path of an airplane and the horizontal plane. It is a measure of the direction and steepness of the airplane's trajectory through the air.

## How is flight path angle related to the airplane's speed?

The flight path angle is directly related to the airplane's speed. A steeper flight path angle indicates a higher speed, while a shallower flight path angle indicates a lower speed.

## What factors affect the flight path angle of an airplane?

The flight path angle of an airplane can be affected by several factors, including the angle of the airplane's wings, the amount of thrust from the engines, the weight and balance of the airplane, and external forces such as wind and turbulence.

## What is the ideal flight path angle for takeoff and landing?

The ideal flight path angle for takeoff and landing is typically between 5 and 10 degrees, depending on the type of airplane and the conditions. This allows for a smooth ascent or descent while maintaining a safe speed and altitude.

## How does the flight path angle affect the overall flight of an airplane?

The flight path angle has a significant impact on the overall flight of an airplane. A steeper flight path angle can result in a faster climb or descent, while a shallower flight path angle can result in a slower climb or descent. It also affects the amount of lift and drag on the airplane, which can impact fuel efficiency and maneuverability.

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