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How Far Should You Taxi Behind A Jet?

This story was made in partnership with AOPA Pilot Protection Services. Make sure your certificates are protected before your next flight. Learn more and get started here.

Whether you're following a Boeing 747 or Citation Jet, turbine engines pose a unique threat to your aircraft.

Exhaust Velocities Stronger Than A Category 5 Hurricane

Turbine engines can produce anywhere from 1,000 to over 100,000 lbs of thrust.

The FAA briefly mentions jet blast in AIM 4-3-18, but doesn't get into much detail, so we looked to Boeing to find out more.

Data from Boeing shows what a hazard exhaust gas can be. The figure below shows a jet producing an exhaust velocity of 375 mph. 100 feet behind the nozzle, the exhaust speed still exceeds 230 mph.


Following the same ratio, a jet that's producing a much lower 150 mph of exhaust thrust at the engine nozzle can still create exhaust velocities exceeding 90 mph 100 feet behind the engine.

Report: Jet Blast Bends C172

Exhaust wake doesn't just apply to large aircraft, like a Boeing. Take the following report from General Aviation News:

A Cessna 172 pilot reported that while on a taxiway at the airport in Morristown, N.J., under air traffic control (ATC) instruction, the Cessna 172 encountered jet blast, originating from a larger turbine-powered airplane being marshaled by ground personnel (Falcon 7X).

The 172's empennage lifted and the propeller and left-wing struck the ground, which resulted in substantial damage to the firewall.

Probable cause: The pilot's failure to maintain a safe taxi distance from a large turbine-powered airplane, resulting in an encounter of the turbine-powered airplane's jet blast while taxiing.


Breakaway Thrust

Jet pilots often have to momentarily use "breakaway thrust" to get the wheels moving.

This thrust is a lot higher than normal taxi thrust, and usually sits somewhere between 25-40% of total engine power, depending on aircraft type, surface conditions, and weight. Pilots initially apply breakaway thrust to get the wheels moving, and once rolling, bring the power much further back to somewhere between idle and 20% of total engine power.

Breakaway thrust is one of the things you should be most concerned about if you're taxiing behind a turbine aircraft.

According to Boeing data, the exhaust hazard area for breakaway thrust extends to 400 feet behind large aircraft. For takeoff thrust, the hazard area extends up to 1,900 feet behind the aircraft.

The following demonstration shows just how powerful jet exhaust can be at high power settings. Ground vehicles and light aircraft simply don't stand a chance.

How Far Back Should You Taxi?

Let's say you're flying a light single-engine piston, and you're taxiing behind a transport category jet.

According to the data above, you should give yourself at least 400 feet of room behind the preceding aircraft...let's call that 500 feet to be extra cautious.

To better visualize 500 feet, imagine how far it is from the threshold to the 1,000-foot markers when you're ready for takeoff. Half that distance is the most conservative limit for how far you should trail a large jet in front of you. The smaller the jet, the less room you'll need. But that doesn't mean the hazards disappear.

Be Cautious In The Ramp Area Too

When you park your airplane, always have it tied down with the gust lock installed. And if you're parking at an airport with lots of jet traffic, have the FBO park your airplane safely away from the main loading area.

Have you gotten caught in jet blast? Tell us about your experience in the comments below.

Protect your certificate with AOPA Pilot Protection Services. Learn more and get started here.

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