When pilots are requested by air traffic control to give their aircraft type and prefix on first contact, they will say “heavy” after the flight number if their aircraft meets the heavy aircraft criteria set by the International Civil Aviation Organization (ICAO). This article explores the reasons behind saying “heavy” and the purpose it serves in aviation communications.
What Does “Heavy” Mean in Aviation?
In aviation, “heavy” is a term used to identify an aircraft with a maximum takeoff weight (MTOW) of 300,000 pounds (136,077 kg) or more. This includes larger aircraft types like the Boeing 747, Airbus A380, and Antonov AN-225. Simply put, if an aircraft is over 300,000 pounds, the pilots are required to state “Heavy” after their callsign when first contacting air traffic control on any given flight.
For example, a pilot would say “United Airlines flight 421, heavy” or “British Airways flight 101, heavy.” This immediately informs air traffic control and other aircraft in the vicinity that there is a large, heavy airplane joining their airspace or traffic flow.
Why Do Pilots Have to Say “Heavy”?
There are several important reasons pilots are required to state “heavy” when controlling their large aircraft:
1. Wake Turbulence Separation
Wake turbulence refers to the vortices or spirals of air that trail behind an aircraft as it passes through the sky. All aircraft produce wake turbulence, but larger planes like heavy jets produce significantly more powerful disturbances.
The wake can be hazardous to smaller aircraft flying behind or below heavy jets, as it can cause instability or even loss of control. As such, air traffic control is required to apply extra spacing between heavy jets and smaller aircraft to maintain safe separation.
By using the “heavy” designation, pilots immediately inform air traffic control that extra spacing from other planes is required for wake turbulence mitigation.
2. Traffic Flow and Sequencing
Knowing an aircraft is heavy also allows air traffic control to better sequence and space traffic within the airspace and at airports. Heavy jets fly faster approach speeds, take up more room on taxiways, and require longer runways. Identifying them early allows controllers to properly integrate them into the traffic flow.
At congested airports, controllers can use the “heavy” designation to sequence heavier and slower moving jets appropriately to maximize throughput while maintaining safety.
3. Situational Awareness
Extending beyond just controllers, stating “heavy” also increases situational awareness for all pilots operating in the same airspace or environment. Pilots are responsible for maintaining visual separation and following proper approach/departure procedures.
Knowing callsigns with heavy aircraft allows pilots to prepare for the extra wake turbulence and adjust their speed/position accordingly, particularly when flying behind or around one.
4. Aircraft Performance Factors
Heavy aircraft require longer runways, have slower climb rates, and fly wider turns at lower maneuverability compared to smaller planes. Identifying them provides better awareness for controllers to issue instructions or clearances that accommodate these limitations.
For example, controllers may offer different approach/departure routings or ensure longer runways are available based on the performance differences of these large jets.
What Qualifies as a Heavy Aircraft?
As mentioned earlier, the primary factor that defines a heavy aircraft is maximum takeoff weight. Per ICAO standards, any aircraft over 300,000 pounds MTOW requires the heavy designation. This includes, but is not limited to:
- Boeing 747 all variants
- Boeing 777 all variants
- Airbus A380 all variants
- Antonov AN-124
- Lockheed C-5 Galaxy
Some examples of aircraft that fall under the 300,000 pound threshold and are NOT considered heavy include:
- Boeing 737
- Airbus A320 family
- Bombardier CRJ regional jets
- Embraer E-Jet family
- Boeing 757
- Boeing 767
- Airbus A300
Regulations Regarding the “Heavy” Designation
Use of the term heavy is mandated by aviation regulations worldwide, including:
- FAA 7110.65 Air Traffic Control Handbook – U.S.
- ICAO Annex 10 Volume II – International Standards
- Eurocontrol Manual of Air Traffic Services – Europe
Pilots are required to state heavy when operating any aircraft over the 300,000 pound MTOW threshold under these aviation authority regulations. Failure to comply could result in penalties or license suspension.
“Super” Designation for A380 and AN-225
In addition to “heavy,” the very largest aircraft including the Airbus A380 and Antonov AN-225 require an additional designation – “super.” Air traffic control needs to be specifically informed when these extra-large jets are operating to ensure proper wake turbulence spacing and handling.
For example, an A380 callsign would sound like “Singapore Airlines flight 101, super.” Only the Airbus A380 and Antonov AN-225 currently meet the criteria for this “super” designation.
Special Handling for Heavy Aircraft
Once air traffic control is aware of a heavy aircraft in their airspace or airport environment, they can implement special handling procedures to maintain safety and smooth operations. This includes:
Increased Wake Turbulence Separation
Controllers are required to apply extra spacing behind and below heavy jets to allow wake turbulence to dissipate. Standard separations are increased:
| Aircraft Type | Separation Minimum |
| Heavy behind heavy jet | 4 miles |
| Small aircraft behind heavy jet | 6 miles |
| Small aircraft behind A380 | 10 miles |
Leaving Approach and Departure Corridors
Controllers will vector aircraft onto diverging headings when able to mitigate wake encounters in terminal airspace.
Awareness on Adjacent Runways
Controllers advise pilots on adjacent runways if a heavy aircraft is using a nearby parallel runway, allowing them to prepare for wake impact.
Gap for Heavy on Rollout
The tower will provide a longer gap for a heavy aircraft to land on the runway, allowing time to exit before the next arrival. This prevents heavy/large jet collisions on the runway.
Verbal Advisory of Heavy Traffic
Controllers will proactively advise pilots, especially at key points in the approach and departure, informing them of wake turbulence from nearby heavy jets.
Pilot Procedures for Operating Heavy Aircraft
For pilots of heavy aircraft, they also follow certain standard procedures to reduce their wake impact on other planes:
- Stating “heavy” on all initial radio calls
- Avoiding unnecessary maneuvers below 3000 feet AGL
- Planning well-in-trail wake turbulence avoidance with air traffic control
- Briefing the FO on wake mitigation procedures
- Being alert for adjacent heavy aircraft and wake encounters
Why Pilots Cannot Omit the “Heavy” Designation
Even if the heavy aircraft is clearly obvious over the radio, such as a pilot with a thick foreign accent stating “Singapore 380”, the heavy designation cannot be omitted. Some reasons why include:
- Prevents radio misunderstandings of aircraft type
- Ensures standard phraseology per ATC regulations
- Reinforces wake category awareness for controllers
- Confirms both pilots have briefed and are aware of wake procedures
Stating “heavy” also eliminates any ambiguity on aircraft weight if callsigns are similar, such as Boeing 747 vs 777 heavy variants.
Recent Changes – 747 and A380 No Longer “Super”
In the early 2000s when the A380 first entered service, it received the “super” designation due to its unprecedented size and wake turbulence. The Boeing 747 also received this distinction decades prior when it was significantly larger than other jets at the time.
However, as newer generation aircraft like the 777 and 787 entered service, differences between the largest heavies and smallest heavies have reduced. In 2014, ICAO removed the “super” terminology for the 747 and A380, standardizing on “heavy” for simplicity and consistency.
Exceptions – When Heavy is Not Required
While most heavy jets over 300,000 pounds require the “heavy” designation, there are some exceptions when it may be omitted:
- On subsequent radio calls after initially stating heavy
- When only operating light aircraft are on frequency
- Clear visibility allows controllers to visually identify heavy jets
- Enroute high altitude cruising away from other traffic
However, stating “heavy” is required on initial check-in or when transitioning to a new ATC sector or frequency.
Future Use of “Heavy” as More Jets Cross Threshold
As aircraft like the Boeing 777, 787, and Airbus A350 continue growing in size and weight with new subvariants, the number of jets exceeding 300,000 pounds is increasing. This means controllers can expect to hear “heavy” more frequently in the future.
However, wake turbulence separation minimums are not likely to be further increased. 300,000 pounds already captures the highest wake turbulence generating aircraft like the A380. Further segmenting would reduce airport throughput.
Conclusion
When airline pilots say “heavy” after their callsign, it serves an important purpose in aviation safety and communications. Identifying heavy aircraft alerts controllers to apply proper wake turbulence separation, sequence traffic efficiently, and allows surrounding pilots to prepare for wake encounters.
Use of “heavy” will likely increase in the future as more large aircraft types begin operating at major airports worldwide. But the terminology will continue providing a simple standardized means of classifying the very largest airliners over 300,000 pounds.
