What is the flap extension schedule on approach for an airliner?
(Boeing 777 manual.)

Substitute altitudes with position to runway. Near an airport an airliner usually flies at around 200 KIAS, this is when you select flaps 1.

Subsequent flap settings are also combined with selecting a lower speed as shown above. The speed tape makes it easy. Flaps 5 should be down by the final intercept path to the localizer or before turning base. Flaps 20 when established on the localizer. Then comes gear down and flaps 30 before the glide-slope is captured.



Initially you wrote PMDG, I recommend check their manuals, they are usually very informative.

For normal procedures on a Boeing 737, the flap settings 2, 10, and 25 are usually also skipped. So it's 1, 5, 15, and 30/40. Non-normal procedures differ.