# [SOLVED]Flight path angle concept question

#### dwsmith

##### Well-known member
Can a flight path angle be 356 degrees?

#### Sudharaka

##### Well-known member
MHB Math Helper
Can a flight path angle be 356 degrees?
Hi dwsmith,

Depends on the way it's defined I presume. If it's defined as, angle between the flight path vector and the horizon (refer >>this<<) then 356 degrees will be the same as 360-356=4 degrees.

Kind Regards,
Sudharaka.

#### dwsmith

##### Well-known member
Hi dwsmith,

Depends on the way it's defined I presume. If it's defined as, angle between the flight path vector and the horizon (refer >>this<<) then 356 degrees will be the same as 360-356=4 degrees.

Kind Regards,
Sudharaka.
Originally it was -4 so I added 360 to get the positive. So I can then subtract and say it is positive?

#### Sudharaka

##### Well-known member
MHB Math Helper
Originally it was -4 so I added 360 to get the positive. So I can then subtract and say it is positive?
Where did you encounter this question and can you please tell us how the flight path angle is defined in the book that you use? I presume that it is defined as an angle in-between -180 and +180.

#### dwsmith

##### Well-known member
Where did you encounter this question and can you please tell us how the flight path angle is defined in the book that you use? I presume that it is defined as an angle in-between -180 and +180.
$$\gamma = \tan^{-1}\left(\frac{e\sin\nu}{1 + e\cos\nu}\right)$$
where $\nu$ is the true anomaly and e is the eccentricity of the orbit.