diff --git a/src/main/flight/imu.c b/src/main/flight/imu.c
index d3f7a1866..e363a2f97 100644
--- a/src/main/flight/imu.c
+++ b/src/main/flight/imu.c
@@ -264,8 +264,12 @@ static int16_t calculateHeading(t_fp_vector *vec)
     float sinePitch = sinf(anglerad[AI_PITCH]);
     float Xh = vec->A[X] * cosinePitch + vec->A[Y] * sineRoll * sinePitch + vec->A[Z] * sinePitch * cosineRoll;
     float Yh = vec->A[Y] * cosineRoll - vec->A[Z] * sineRoll;
+    //TODO: Replace this comment with an explanation of why Yh and Xh can never simultanoeusly be zero,
+    // or handle the case in which they are and (atan2f(0, 0) is undefined.
     float hd = (atan2f(Yh, Xh) * 1800.0f / M_PIf + magneticDeclination) / 10.0f;
     head = lrintf(hd);
+
+    // Arctan returns a value in the range -180 to 180 degrees. We 'normalize' negative angles to be positive.
     if (head < 0)
         head += 360;