Wake turbulence: ground, takeoff, en route avoidance and spacing
On the ground:
- Wait a few minutes before crossing a live runway a large aircraft just used.
- Holding near an active runway: expect wake turbulence.
- Avoidance not possible on the ground: wait (2 minutes usually enough) (TC AIM AIR 2.9.2, Note 1).
Taking off:
| Situation | Action | Cite |
|---|---|---|
| Intersection clearance, or parallel or crossing runway ops near a large aircraft | Avoid any heading crossing below and behind it. Intersection takeoff is closer to a preceding aircraft's vortices | TP 1102 |
| Unsure of timing | Delay up to 2 min if preceding aircraft just landed, 4 min if just departed. Larger aircraft, longer wait. Light aircraft cleared immediately behind a heavy: request delay | TP 1102 |
| Large aircraft's very low approach and overshoot | If cleared for takeoff, decline and tell ATC why. Its vortices can lie between its flight path and the runway surface | PSTAR 6.01; TC AIM AIR 2.9.2 |
| Departing behind a heavy | Lift off before its rotation point. Climb above its climb path until clear of the wake | TC AIM AIR 2.9.2; PHAK ch.14 |
| Departing behind a landed aircraft | Become airborne beyond its touchdown point | TP 1102 |
- Simple version: after a departure, use the near end of the runway. After a landing, use the far end (TP 1102, Fig. 2-45).
En route VFR:
| Situation | Action | Cite |
|---|---|---|
| Behind and less than 1 000 ft below a large aircraft | Stay alert | TC AIM RAC 4.1.1 |
| Below and behind other aircraft, especially at low altitude | Avoid the area | TC AIM AIR 2.9 |
| Meeting or overtaking one on the same track | Offset laterally, preferably upwind | - |
En route spacing (TC AIM RAC 11.7.13):
- Wake from aircraft climbing or descending through your altitude.
| Traffic | Roughly |
|---|---|
| Opposite direction | 12 to 15 miles after passing 1,000 ft below |
| Same direction | 12 to 15 miles behind and 1,000 ft below |
References
- TC AIM AIR 2.9
- TC AIM AIR 2.9.2
- TC AIM AIR 2.9.2, Note 1
- TC AIM RAC 4.1.1
- TC AIM RAC 11.7.13
- TP 1102 Take-off: Wake Turbulence
- PHAK ch.14
- PSTAR 6.01