Why must caution be used when selecting APP mode prior to LOC capture?

Prepare for the Delta 737 PA-LOD Exam with flashcards and multiple choice questions. Each question includes hints and explanations, ensuring you're ready for exam day!

Multiple Choice

Why must caution be used when selecting APP mode prior to LOC capture?

When you select APP, the autopilot switches to follow the ILS approach path, focusing on localizer (and glideslope if available) guidance. In this mode, VNAV from the flight plan is disabled, so the vertical guidance you normally rely on from VNAV is no longer active. That means you must manage altitude manually or with another vertical mode until the approach guidance is captured, to avoid descending with an unsupported vertical path. APP can be used to capture the localizer and glideslope, so the concern isn’t that LOC can’t be captured with APP or that APP only works after LOC; it’s about the loss of VNAV guidance once APP is engaged.

When you select APP, the autopilot switches to follow the ILS approach path, focusing on localizer (and glideslope if available) guidance. In this mode, VNAV from the flight plan is disabled, so the vertical guidance you normally rely on from VNAV is no longer active. That means you must manage altitude manually or with another vertical mode until the approach guidance is captured, to avoid descending with an unsupported vertical path. APP can be used to capture the localizer and glideslope, so the concern isn’t that LOC can’t be captured with APP or that APP only works after LOC; it’s about the loss of VNAV guidance once APP is engaged.

More practice questions