Who Should Read This Section?
This part of the course applies to all ATC positions, and should be read before proceeding to the lessons covering specific positions (GND, TWR, etc).
New students should spend a good amount of time reviewing this lesson and the source material referenced in it, because subsequent lessons will build on what is learned here.
New students should spend a good amount of time reviewing this lesson and the source material referenced in it, because subsequent lessons will build on what is learned here.
General Concepts
Purpose of air traffic control
When aviation was born in the early 20th Century, obviously no air traffic control system existed. This continued to be the case until the 1930s, when a limited air traffic control system was introduced. The air traffic control system was created to reduce the risk of in‐flight collisions, but covered a limited geographic area. Nationwide air traffic control didn't begin to form until the late 1950s, and came as a result of a very high‐profile collision between a TWA Constellation and United DC-7 over the Grand Canyon (at the time of the accident, these aircraft were operating in uncontrolled airspace). The system we have today is much more sophisticated than the original system, and deals with volumes of traffic that the ATC system creators couldn't dream of. The purpose of the system remains the same, however. It exists to prevent collisions between participating aircraft.
IFR versus VFR
When a pilot operates an aircraft, he chooses one of two sets of flight rules under which he'll operate. One option is to fly under visual flight rules (VFR). When operating under VFR, the pilot generally may fly any route he chooses and fly at any altitude below 18,000', without contacting air traffic control. The pilot is required to see other aircraft and avoid them. To ensure he can see other aircraft, the pilot must meet certain inflight visibility requirements and remain certain minimum distances from clouds. Contact with ATC is required to operate in certain classes of airspace; these will be covered in other lessons.
A second option for the pilot is to operate under instrument flight rules (IFR). To operate under IFR, the pilot must obtain a clearance from air traffic control. The controller is required to ensure that all IFR aircraft are safely separated from other IFR aircraft. Because of the separation provided by the controller, there are no visibility or cloud clearance requirements for IFR pilots. With few exceptions, IFR aircraft are not separated from VFR aircraft. When visibility permits, IFR pilots are expected to see and avoid VFR aircraft.
Situations not addressed in the 7110.65
For most situations, you'll find specific guidance on phraseology and methods in the 7110.65 document. When you have a situation that is not covered by it, use good judgment in deciding on phraseology and methods.
{Reference: FAAO 7110.65 1–1–1}
Altitudes
Altitudes are normally referenced to a height above sea level. For example, when an aircraft is instructed to “maintain five thousand” that means the pilot is required to maintain an altitude that is 5000 feet above sea level. Most altitude references in the 7110.65 refer to altitudes above sea level.
In some publications the abbreviation “MSL” or “ASL” will be used to reinforce that altitudes are in reference to sea level. “MSL” is an abbreviation for “Mean Sea Level” or to put it more clearly “above Mean Sea Level.” Sometimes, you will still see the abbreviation “ASL” used as well; it stands for “Above Sea Level.”
There are publications that reference “AGL” altitudes as well. “AGL” stands for “Above Ground Level.” Most correctly, those altitudes should refer to the aircraft's height above the ground directly below it. However, AGL altitudes sometimes refer to heights above airport elevation (used on approach charts with circling minimums), or heights above touchdown zone elevation (used on approach charts with straight‐in minimums).
Definitions
Numerous terms are defined for use in this section of the 7110.65. Ensure you are familiar with where to find these as you move through your training.
{Reference: FAAO 7110.65 1–2–1}
Course Definitions
Certain sections of the 7110.65 will refer to the relationship of two aircrafts courses. These terms are specifically defined in this section:
Here is the graphic from the 7110.65 depicting these relationships:
{Reference: FAAO 7110.65 1–2–2}
Examples of Phraseology
Most sections of the 7110.65 provide examples of how to phrase instructions. If these items begin with the term “Phraseology,” then the use of that exact phraseology is required. If these items begin with the term “Example,” it is either providing examples of how to utilize the “phraseology” described above it, or just providing an example of how one might phrase an instruction.
“Phraseology” describes required phraseology, “Example” describes suggested phraseology.
{Reference: FAAO 7110.65 1–2–5-g & h}
Abbreviations
This section lists a large number of abbreviations used in the 7110.65.
{Reference: FAAO 7110.65 1–2–6}
When aviation was born in the early 20th Century, obviously no air traffic control system existed. This continued to be the case until the 1930s, when a limited air traffic control system was introduced. The air traffic control system was created to reduce the risk of in‐flight collisions, but covered a limited geographic area. Nationwide air traffic control didn't begin to form until the late 1950s, and came as a result of a very high‐profile collision between a TWA Constellation and United DC-7 over the Grand Canyon (at the time of the accident, these aircraft were operating in uncontrolled airspace). The system we have today is much more sophisticated than the original system, and deals with volumes of traffic that the ATC system creators couldn't dream of. The purpose of the system remains the same, however. It exists to prevent collisions between participating aircraft.
IFR versus VFR
When a pilot operates an aircraft, he chooses one of two sets of flight rules under which he'll operate. One option is to fly under visual flight rules (VFR). When operating under VFR, the pilot generally may fly any route he chooses and fly at any altitude below 18,000', without contacting air traffic control. The pilot is required to see other aircraft and avoid them. To ensure he can see other aircraft, the pilot must meet certain inflight visibility requirements and remain certain minimum distances from clouds. Contact with ATC is required to operate in certain classes of airspace; these will be covered in other lessons.
A second option for the pilot is to operate under instrument flight rules (IFR). To operate under IFR, the pilot must obtain a clearance from air traffic control. The controller is required to ensure that all IFR aircraft are safely separated from other IFR aircraft. Because of the separation provided by the controller, there are no visibility or cloud clearance requirements for IFR pilots. With few exceptions, IFR aircraft are not separated from VFR aircraft. When visibility permits, IFR pilots are expected to see and avoid VFR aircraft.
Situations not addressed in the 7110.65
For most situations, you'll find specific guidance on phraseology and methods in the 7110.65 document. When you have a situation that is not covered by it, use good judgment in deciding on phraseology and methods.
{Reference: FAAO 7110.65 1–1–1}
Altitudes
Altitudes are normally referenced to a height above sea level. For example, when an aircraft is instructed to “maintain five thousand” that means the pilot is required to maintain an altitude that is 5000 feet above sea level. Most altitude references in the 7110.65 refer to altitudes above sea level.
In some publications the abbreviation “MSL” or “ASL” will be used to reinforce that altitudes are in reference to sea level. “MSL” is an abbreviation for “Mean Sea Level” or to put it more clearly “above Mean Sea Level.” Sometimes, you will still see the abbreviation “ASL” used as well; it stands for “Above Sea Level.”
There are publications that reference “AGL” altitudes as well. “AGL” stands for “Above Ground Level.” Most correctly, those altitudes should refer to the aircraft's height above the ground directly below it. However, AGL altitudes sometimes refer to heights above airport elevation (used on approach charts with circling minimums), or heights above touchdown zone elevation (used on approach charts with straight‐in minimums).
Definitions
Numerous terms are defined for use in this section of the 7110.65. Ensure you are familiar with where to find these as you move through your training.
{Reference: FAAO 7110.65 1–2–1}
Course Definitions
Certain sections of the 7110.65 will refer to the relationship of two aircrafts courses. These terms are specifically defined in this section:
- Same courses – Those courses with an angular difference of less than 45°
- Crossing course – Intersecting courses which have an angular difference between 45° and 135°
- Opposite/reciprocal courses – Courses with an angular difference of more than 135°
Here is the graphic from the 7110.65 depicting these relationships:
{Reference: FAAO 7110.65 1–2–2}
Examples of Phraseology
Most sections of the 7110.65 provide examples of how to phrase instructions. If these items begin with the term “Phraseology,” then the use of that exact phraseology is required. If these items begin with the term “Example,” it is either providing examples of how to utilize the “phraseology” described above it, or just providing an example of how one might phrase an instruction.
“Phraseology” describes required phraseology, “Example” describes suggested phraseology.
{Reference: FAAO 7110.65 1–2–5-g & h}
Abbreviations
This section lists a large number of abbreviations used in the 7110.65.
{Reference: FAAO 7110.65 1–2–6}
