To solve this problem, we need to calculate the following:

1. Great Circle Distance: This is the shortest distance between two points on the surface of a sphere. It can be calculated using the haversine formula or the spherical law of cosines.
2. Initial Course (or Bearing): This is the angle from the starting point to the endpoint at the departure position.
3. Final Course (or Bearing): This is the angle from the arrival position back towards the departure position.

Given:

• Departure Position $P_1$: $56^\circ 20' \text{N}, 008^\circ 12' \text{W}$
• Arrival Position $P_2$: $52^\circ 12' \text{N}, 057^\circ 10' \text{W}$

Let's start by converting these coordinates into decimal degrees and proceed with the calculations:

1. Convert Coordinates to Decimal Degrees

• $P_1$:

  • Latitude: $56^\circ 20'$ = $56 + \frac{20}{60} = 56.3333^\circ$ N
  • Longitude: $008^\circ 12'$ = $- (8 + \frac{12}{60}) = -8.2^\circ$ W

• $P_2$:

  • Latitude: $52^\circ 12'$ = $52 + \frac{12}{60} = 52.2^\circ$ N
  • Longitude: $057^\circ 10'$ = $- (57 + \frac{10}{60}) = -57.1667^\circ$ W

2. Great Circle Distance Calculation

Using the spherical law of cosines formula: $d = R \cdot \arccos(\sin \phi_1 \cdot \sin \phi_2 + \cos \phi_1 \cdot \cos \phi_2 \cdot \cos(\lambda_2 - \lambda_1))$ where:

• $R$ is the Earth’s radius (mean radius = 6,371 km),
• $\phi_1$ and $\phi_2$ are the latitudes of $P_1$ and $P_2$ in radians,
• $\lambda_1$ and $\lambda_2$ are the longitudes of $P_1$ and $P_2$ in radians.

3. Initial and Final Course Calculations

For the initial bearing $\theta_1$ from $P_1$ and the final bearing $\theta_2$ approaching $P_2$, we use: $\theta = \arctan \left( \frac{\sin(\Delta \lambda) \cdot \cos \phi_2}{\cos \phi_1 \cdot \sin \phi_2 - \sin \phi_1 \cdot \cos \phi_2 \cdot \cos(\Delta \lambda)} \right)$ where $\Delta \lambda = \lambda_2 - \lambda_1$.

I'll perform these calculations for an accurate solution.The results for the given positions are as follows:

1. Great Circle Distance: Approximately 3144 km
2. Initial Course (Bearing) from the departure position: $77.42^\circ$
3. Final Course (Bearing) approaching the arrival position: $298.02^\circ$

Would you like a detailed explanation of any part of these calculations, or do you have any other questions?

Here are some related questions that expand on this topic:

1. How is the great circle distance different from a straight line distance?
2. What other methods can be used to calculate the distance between two points on the Earth’s surface?
3. Why is it necessary to convert coordinates to radians when calculating distances and bearings?
4. How can we verify if these bearings are correct using different methods?
5. What would be the impact of Earth's ellipsoidal shape on these calculations?

Tip: When dealing with navigation problems, always ensure to check if your results make sense directionally and distance-wise, especially for long distances where the curvature of the Earth has a significant impact.