FAA Aircraft Dispatcher (ADX)Flight Planning and PerformanceMedium
A dispatcher is monitoring the arrival sequence at a busy hub. A Cessna 172 (Small category) will be landing on the same runway immediately behind a Boeing 747 (Heavy category). Per FAA wake turbulence separation standards, what minimum radar separation is required between the two aircraft?
- A5 NM
- B4 NM
- C6 NM
- D3 NM
Show answer & explanationAnswer & explanation
Correct answer: C. 6 NM
FAA wake turbulence separation standards require 6 NM radar separation when a Small category aircraft is following a Heavy category aircraft on approach or departure, due to the significant wake vortex hazard posed to light aircraft.
Why the other options are wrong
- A. 5 NM applies to a Large or B757 following a Heavy.
- B. 4 NM applies to a Heavy following a Heavy, not a Small following a Heavy.
- D. 3 NM is a standard minimum radar separation with no wake turbulence consideration.
Wake Turbulence Separation
FAA-mandated minimum distances between aircraft based on weight category to avoid wake vortex encounters.
- Heavy behind Heavy: 4 NM
- Large/B757 behind Heavy: 5 NM
- Small behind Heavy: 6 NM
Memory trick: The smaller you are, the farther you stay from a Heavy's swirl.