A pilot is flying a localizer back course (LOC BC) approach using a standard VOR/LOC indicator that does not have back-course compensation. During the approach, the CDI needle deflects to the right of center. What action should the pilot take to correct back onto the course?
- ATurn right, since the needle indicates the course is to the right of the aircraft, the same as a front-course ILS
- BTurn left, because indications are reversed on a back course approach when using a standard (non-reverse-sensing) indicator
- CMaintain the current heading, since back course approaches do not require correction for needle deflection
- DDescend immediately, since the needle deflection has no bearing on lateral guidance during a back course approach
Show answer & explanationAnswer & explanation
Correct answer: B. Turn left, because indications are reversed on a back course approach when using a standard (non-reverse-sensing) indicator
When flying a localizer back course with a standard VOR/LOC indicator (no HSI or back-course reversal function), the needle indications are reversed relative to a front-course approach. A right needle deflection actually indicates the course is to the LEFT, so the pilot must turn left (fly away from the needle deflection) to correct back onto course, unless the aircraft's indicator provides reverse-sensing correction automatically.
Why the other options are wrong
- A. Incorrect — this is correct only for front-course indications, not reversed back-course sensing
- C. Incorrect — lateral corrections are still required to remain on the approach course
- D. Incorrect — needle deflection is critical lateral guidance information, not irrelevant to descent
Localizer Back Course (LOC BC) Reverse Sensing
When flying a back course approach with a standard (non-HSI, non-reverse-sensing) VOR/LOC indicator, CDI needle deflections are reversed compared to a front-course approach, requiring the pilot to turn away from the needle to correct.
- HSIs typically auto-correct for back course sensing
- Standard VOR/LOC indicators require manual reverse interpretation
- Turning toward the needle on a back course will worsen the deviation
Memory trick: Back course, backwards needle — fly away, not toward.