A while back, I viewed a tweet about an Air Traffic Control (ATC) conversation in New York, where JFK ATC got a little bit confused about an aircraft type. American Airlines (AA) Flight 32 was incorrectly called a “heavy” aircraft, likely because for so long that flight was operated by a Boeing 767-200. Ever since AA debuted their new Airbus A321 on the LAX-JFK route, this flight no longer needs to use the “heavy” designation, but that didn’t stop the ATC staff from using old habits. It made me question, at what point does an aircraft become “heavy”?
When aircraft are approaching or departing an airport, they must use special designations to help avoid the wake turbulence from other aircraft. Larger aircraft, like a 767 or an A340, need more space behind them to prevent the wake vortices generated by the larger wing span from impacting other aircraft. The bigger the aircraft, the longer the distance.
The dangers are real, as all over the world a number of incidents have occurred that can be attributed to a wake vortex. From the crash of an XB-70 in the 60’s to some involving more modern aircraft in the last 10 years (including an A380 in Sydney).