When an aviation radio call includes the word “heavy” as an addition to a callsign, it references an aircraft’s weight. But the pilots of a 747 aren’t letting ATC know they ate too many donuts at breakfast—the term “heavy” is used as a reminder to all involved that an aircraft leaves a more severe wake in its path.
Why are some planes called “Heavy?”
All aircraft generate wake turbulence while in flight and the heavier an aircraft, the greater the turbulence behind it. Wake turbulence poses a major risk to other aircraft, so pilots and ATC use the term “heavy” in radio transmissions as a reminder that the aircraft’s wake may be dangerous to others passing behind or below the flightpath of these larger-mass aircraft.
FAA Weight Classes
The FAA classifies planes weighing over 300,000 pounds—a Boeing 747 or Airbus A340, for example—as “heavy.” The official weight classes include:
- Small: 41,000 pounds or less maximum certified takeoff weight
- Large: More than 41,000 pounds and up to 300,000 pounds maximum certified takeoff weight
- Heavy: 300,000 pounds or more maximum certified takeoff weight
- Super: Airbus A-380-800 (A388) and the ANTONOV An-225 (A225)
What is Wake Turbulence?
A function of lift, wake turbulence is caused by counter-rotating vortices trailing behind an aircraft. To put it simply: when an airplane flies, it disturbs the air it flies through. This can cause a major hazard for other aircraft encountering the wake.
The heavier and slower an aircraft, the greater the wake, so it’s typically the case that aircraft create the most wake during takeoff, departure, approach and landing. The heavier aircraft pose the most danger to the lightest aircraft, so a departing airliner will leave a massive wake, capable of upsetting airplanes taking off or landing behind it. Though wakes dissipate after a few minutes, air traffic controllers often use the phrase, “caution wake turbulence” or use the word “heavy” when referring to larger planes on the radio.
Pilots avoid wake turbulence by:
- Taking off or landing before a departing aircraft’s lift-off point
- Remaining above and upwind of the flight path of any traffic you’re following
- Taking off or landing beyond a previously-arrived aircraft’s touchdown point
Be Careful!
Landing late one night at a major Southern California airport, I unsuspectingly flew a Cessna 172 into the wake of a just-landed 737. One second I was rounding out into ground effect and the next I found myself tossed into an induced roll—banked 50 degrees left only 15 feet above the ground. Had I not been ready at the controls to go around and execute a timely recovery, I might not be writing today. Wake turbulence can be deadly, so take the warnings “heavy” and “caution wake turbulence” seriously.
You can ensure you’re covered in the event of a wake turbulence-related accident with excellent coverage from SkyWatch. Aircraft owners and renters can obtain coverage by the day, week, month or year, meaning pilots only pay for what they need.
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FAQs
The FAA classifies planes weighing over 300,000 pounds—a Boeing 747 or Airbus A340, for example—as “heavy.” The official weight classes include: Small: 41,000 pounds or less maximum certified takeoff weight. Large: More than 41,000 pounds and up to 300,000 pounds maximum certified takeoff weight.
What is the meaning of heavy in aviation? ›
The term “heavy” is used in air traffic regulation to describe any aircraft with a maximum takeoff weight (MTOW) of 136 tons (300,000 lb) or more. Aircraft between 7 and 136 tons are “medium” and those less than 7 tons are “light”.
What is a heavy jet? ›
Heavy jets are private jets in the "kingsize" category and have seating for 12 to 14 passengers. They have a range of 10 - 12 flight hours. This allows intercontinental flights without fuelling stops.
What is heavier-than-air aviation? ›
Heavier-than-air vehicles generally achieve flight with aerodynamic lift created by airflow over a surface (usually a wing). There were three basic types of early heavier-than-air vehicles -- kites, gliders and airplanes. Kites are unpowered, tethered craft. Gliders fly freely.
What if a plane is too heavy? ›
Effects of Weight
An overloaded aircraft may not be able to leave the ground, or if it does become airborne, it may exhibit unexpected and unusually poor flight characteristics. If not properly loaded, the initial indication of poor performance usually takes place during takeoff.
What does "heavy" mean in slang? ›
old-fashioned slang. used to describe something such as a situation that is dangerous or unpleasant: Then the police arrived and things got really heavy. SMART Vocabulary: related words and phrases. Serious and unpleasant.
What is a heavy check in aviation? ›
The D check, sometimes known as a "heavy maintenance visit" (HMV), is by far the most comprehensive and demanding check for an airplane. This check occurs approximately every 6-10 years. It is a check that more or less takes the entire airplane apart for inspection and overhaul.
How heavy is Jet A? ›
Typical physical properties for Jet A and Jet A-1
| Jet A-1 | Jet A |
|---|
| Density at 15 °C (59 °F) | 0.804 kg/L (6.71 lb/US gal) | 0.820 kg/L (6.84 lb/US gal) |
| Specific energy | 43.15 MJ/kg (11.99 kWh/kg) | 43.02 MJ/kg (11.95 kWh/kg) |
| Energy density | 34.7 MJ/L (9.6 kWh/L) | 35.3 MJ/L (9.8 kWh/L) |
4 more rowsIn heavier-than-air craft, lift is created by the flow of air over an airfoil. The shape of an airfoil causes air to flow faster on top than on bottom. The fast flowing air decreases the surrounding air pressure. Because the air pressure is greater below the airfoil than above, a resulting lift force is created.
What is the difference between heavy and light aircraft? ›
Light (L) — aircraft types of 7,000 kg or less. Medium (M) — aircraft types more than 7,000 kg but less than 136,000 kg; and. Heavy (H) — all aircraft types of 136 000 kg or more, with the exception of aircraft types in Super (J) category; and.
Materials heavier than air (examples: propane, hydrogen sulfide, ethane, butane, chlorine, sulfur dioxide) have vapor densities greater than 1.0. All vapors and gases will mix with air, but the lighter materials will tend to rise and dissipate (unless confined).
Which is the heavier aircraft? ›
Summary. The Antonov An-225 Mriya holds the record for being the heaviest aircraft ever built, with a maximum take-off weight of 640 tonnes.
Can air be heavier than water? ›
Water is heavier than air because it is DENSER. This means that more water molecules are packed into a given volume. Water density = 1,000 kilograms per cubic meter!!! The water molecule itself, H2O, is actually less massive than a Nitrogen molecule, N2, which makes up 80% of our air.
What is considered heavy in aviation? ›
The FAA classifies planes weighing over 300,000 pounds—a Boeing 747 or Airbus A340, for example—as “heavy.” The official weight classes include: Small: 41,000 pounds or less maximum certified takeoff weight. Large: More than 41,000 pounds and up to 300,000 pounds maximum certified takeoff weight.
Do heavier planes fly slower? ›
Weight Makes a Big Difference
Increasing an aircraft's weight affects its climb performance in two ways: 1) A change in weight changes the drag and power required. 2) A heavier aircraft needs to fly at a faster speed to achieve Vy.
How heavy are planes? ›
2 - How much does the average passenger plane weigh? The weight of an average passenger plane varies depending on the size and type of the plane. However, the weight of an average passenger plane ranges from 80,000 to 176,000 pounds.
What does the air is heavy mean? ›
The phrase "the air was heavy" is correct and can be used in written English. It is used to describe a situation where the air is thick, muggy, and oppressive. Example sentence: The air was heavy with the smell of summer rain.
What is hard vs heavy landing? ›
Hard landings result from excessive force and can lead to immediate structural damage and system malfunctions. Heavy landings involve increased weight and might result in accelerated wear and tear over time.
What does "heavy Mayday" mean? ›
There's no such thing as a "heavy mayday" but an aircraft of over 300,000lb is classed as a "heavy" aircraft and the crew usually includes that in their callsign, so in an emergency the call might be… " Mayday mayday mayday, Interair123 heavy, lost power both engines" (or whatever the emergency is).
