Rotating object

I have a space ship that I want to rotate.

Here is my current code (it executes when .turning = true):

Code:

---

                        a = System.Math.Sin(.destStoppingAngle + System.Math.PI)
                        b = System.Math.Cos(.destStoppingAngle + System.Math.PI)
                        c = System.Math.Sin(.msngFacing)
                        d = System.Math.Cos(.msngFacing)

                        det = a * d - b * c

                        If det > 0 Then

                            .msngFacing = .msngFacing - .ROTATION_RATE * TV.TimeElapsed
                            If det < 0.1 Then
                                .msngFacing = .destStoppingAngle
                                .turning = False
                            End If
                        Else
                            .msngFacing = .msngFacing + .ROTATION_RATE * TV.TimeElapsed
                            If det > 0.1 Then
                                .msngFacing = .destStoppingAngle
                                .turning = False
                            End If
                        End If

---

It works like 95% of the time.... however sometimes it 'jumps' to the destination angle. What would be causing this?

thanks

Canning

What programming language is this?

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