Training Tip: Wake watch

This scenario adds complexity to the basic textbook example used to illustrate how to avoid flying into another aircraft’s invisible wake—but in the real world of airport operations, accidents happen even to experienced pilots under such conditions.

It’s also an example of why it’s important to sharpen your ability to analyze wake turbulence scenarios beyond the basic concepts that explain how to safely take off or land after a larger aircraft has used the same runway. As you begin flying to larger airports with multiple runways and a wider mix of aircraft, it will become a routine exercise for you to assess the wake turbulence hazard those airport operations present.

Whether you must make that assessment on takeoff, on landing, or en route, here are some basic questions to answer.

• What size and speed characterize the wake-generating aircraft? Heavy, clean, and slow are the riskiest combination.
• Can I maintain a flight path above the preceding aircraft’s? Takeoffs and landings should be planned with this goal in mind.
• Is the aircraft I see the correct one to keep track of? Mistaken identities have led to accidents, especially at low altitude before landing.
• How much time will elapse before I arrive at the spot where a wake encounter is likely? If unsure where that point is, the Pilot’s Handbook of Aeronautical Knowledge notes that three minutes provides a safety margin for wake dissipation behind an aircraft that has taken off or landed.
• What basic practices help with avoidance? When taking off behind another aircraft, be sure to be off the ground before the preceding aircraft’s rotation point. At a safe altitude, make an early turn upwind to escape the wake area. Flying your departure behind another departing aircraft, avoid following it at an altitude within 1,000 feet of its altitude. For landing, fly your approach above a preceding aircraft’s descent path. Make it a point to note and touch down beyond where its wheels contacted the ground. Be prepared, as always, to execute a go-around.
• What effect will the wind have? Wingtip vortices “drift with the wind at the speed of the wind.”

Answer to the spot quiz above: The wake's drift in the wind increases risk.