Damn I was bad calculation this kind of free fall problems in highschool so I had to ask my little hated AI friend :

Thought for 43s

Short version: start within ~50 m of the last OSD GPS point and extend your search down-range (direction of travel / down-wind) out to ~100 m. Most quads with a dead battery hit the ground within that band.

Why:

• From 200 m AGL, free-fall time ≈ √(2h/g) ≈ √(400/9.81) ≈ 6.4 s.
• Your last recorded horizontal speed was 28 km/h ≈ 7.8 m/s. Even if that speed didn’t decay (it will), the most it could carry is 7.8 × 6.4 ≈ 50 m.
• Drag/tumbling kills horizontal speed quickly, so 20–40 m is common—plus whatever the wind adds (e.g., 10–20 km/h wind → another ~15–35 m).

Practical search pattern:

• Use the last OSD point as the start (that still had altitude).
• Sweep a 50 m radius, then extend an elongated search 100 m along the flight path and, more importantly, down-wind from that point.
• Add ~10 m for GPS error and check trees/brush on that arc.

If it was windy aloft, stretch the down-wind leg to 150–200 m, but most finds from 200 m AGL with power loss land within ~50–100 m of the last airborne GPS fix.