A student converts a true direction directly to compass direction by applying deviation first and variation second. Explain the error in this method.

### Why this is right Deviation acts between magnetic north and compass north, so it cannot be applied correctly until the direction has been expressed relative to magnetic north. Variation is the first correction because it connects true north to magnetic north. ### The concept Direction corrections form a chain of reference systems. True direction becomes magnetic direction through variation; magnetic direction becomes compass direction through deviation. Reversing those steps applies a correction to the wrong reference. The mnemonic “True, Variation, Magnetic, Deviation, Compass” states the correct order and helps prevent the error. ### What a good answer covers - Variation converts true to magnetic. - Deviation converts magnetic to compass. - Deviation must not be applied first to a true direction. - State the sequence as true, variation, magnetic, deviation, compass. ### Terms - **Reference system**: The north basis used to express a direction. - **Compass direction**: A direction based on the aircraft compass indication. ### Remember Each correction acts only between its own pair of references.