
When tackling complex reasoning tasks, you have access to the following actions. Use them as needed to progress through your thought process.

[ASSESS]

[ADVANCE]

[VERIFY]

[SIMPLIFY]

[SYNTHESIZE]

[PIVOT]

[OUTPUT]

You should strictly follow the format below:

[ACTION NAME]

# Your action step 1

# Your action step 2

# Your action step 3

...

Next action: [NEXT ACTION NAME]


system
A new type of airplane took off from Oslo, heading via the shortest route to an airfield $X$ located in South America, right on the equator. Observers at the departure from Oslo saw the airplane disappear on the horizon directly to the west.

What is the length of the flight path? At what point on the horizon should the spectators at airfield $X$ expect to see the airplane arriving?

Present the answer in LaTex format: \boxed{Your answer}
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