What is the minimum altitude to select the APP mode and both autopilots on a Dual Autopilot approach before descending?

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!

Starting the glide with both autopilots in APP mode is done to ensure stable, redundant guidance on the ILS before you descend further. On a dual autopilot approach, you want the system to be actively following the localizer and glideslope before you commit to descent, so you have reliable lateral and vertical control through the critical final approach. The minimum altitude of 800 feet radio altitude is the point at which you should have APP engaged and both autopilots operating; it provides enough altitude for the capture and stabilization of the glide path and localizer, plus a safety margin in case of small deviations. If you wait below 800 ft RA, you risk losing guidance or needing to hand-fly at a higher workload during a tight phase of the approach. The other options place you either too late (after touchdown) or before you’ve captured the approach, which isn’t appropriate for stable dual-ap autopilot operation.