This is a 2D vertical cross-section of the same microburst encounter: the horizontal axis is distance along the approach track, the vertical axis is altitude. Because the aircraft never moves sideways off the track, the full 3D wind field reduces exactly to this plane — no information is lost by flattening it, since the flight only ever samples wind along z = 0.
Wind field (r = horizontal distance from the microburst center, y = height, R = core radius, H = outflow depth):
Downdraft: w(r,y) = -W_max · exp(-(r/R)²) · sin(π·y/H)
Outflow: U(r,y) = U_max · (r/R) · exp(0.5(1-(r/R)²)) · exp(-y/H)
The quiver field redraws every frame from these formulas — not a cached texture — so the arrows you see are the actual vectors the aircraft is flying through. The hazard is the real F-factor used in FAA/NASA windshear research (Bowles, 1990):
F = (1/g)·(dV_h/dt) − w/V
V_h = wind component along the flight path (+ = tailwind)
w = vertical wind (+ = up, so a downdraft is negative)
V = airspeed, g = 9.81 m/s²
- F < 0.05 — negligible shear.
- 0.05 ≤ F < 0.10 — caution; performance-decreasing shear.
- F ≥ 0.10 sustained — the FAA/ICAO threshold for hazardous windshear.
The flight-dynamics integrator here uses a midpoint (RK2) step rather than a single forward-Euler step, which roughly quarters the numerical error every time you halve the timestep instead of only halving it — verified separately against an analytic relaxation solution.
Autothrottle tries to hold Vref with a thrust-limited response; toggle it off to see how much more dangerous an unmanaged encounter is. The lower strip chart scrolls airspeed, vertical wind and F-factor over time — a live telemetry trace that has no equivalent in a single 3D flythrough.