Checklist: ATC Rules To Live By

The Air Traffic Control procedures handbook, FAA Order 7110.65Z, requires, "controllers … to be familiar with its provisions … that pertain to their operational responsibilities and to exercise their best judgment if they encounter situations … not covered ...” 

Judgment, of course, varies by controller and the amount of traffic on the radio frequency. Rules are rules, but there will always be exceptions to how controllers perform their duties. While everything contained in the 7110.65s is important, there are a few that pilots should understand to help the ATC system flow a bit smoother. 

A Few Basics

Controllers provide ATC services on a “first come, first served” basis with air ambulance flights given priority. They expect pilots to understand the deeper meanings contained in several important words such as, "immediately" used when “expeditious compliance is required to avoid an imminent situation.” In English, that means two airplanes are about to collide. ATC uses "expedite" when prompt compliance is needed to avoid an imminent situation from developing.

From the Tower:

Communication Confirmation

The FAA continues to emphasize the importance of fully acknowledging ATC instructions. Pilots must include their aircraft tail or flight number along with a confirmation of a hold short, an altitude or a heading instruction.

“Cirrus 35 Bravo will hold short of runway 27 Left.” Applied to climb, descent and heading instructions. “Gulfstream 1234 Bravo roger, descend to and maintain flight level 240,” or “Falcon 248, turning right heading 040 and we’re looking for traffic.” Responding with “Gulfstream 34 Bravo … or Falcon 248,” simply won’t cut it. 

Line Up and Wait

Tower controllers use Line Up and Wait instructions to position an aircraft on the runway when traffic elsewhere prevents them from issuing a takeoff clearance. ATC should offer a reason for the Line Up and Wait instruction.  If they don’t, the pilot should ask. ATC will not use LUW at night.

This could happen when another aircraft is departing on a crossing runway or perhaps just appearing in the controller’s view. The point is that Line Up and Wait (LUW) means to be ready to go. Pilots should never accept LUW if they are not quite ready because the tower could clear them for an immediate takeoff or an expedited one. However, if following an LUW instruction, pilots find themselves sitting on the runway for more than a minute or so without a follow-up takeoff clearance, pilots should query the controller. ATC personnel do forget now and again.

Runway Separation

A VFR tower controller need not wait until a departing aircraft has passed the end of the runway to issue a takeoff clearance if, in the controller’s judgment, separation meets agency standards during daylight hours. Practically, that means a small single-aircraft (Category 1) may be cleared for takeoff when a similar aircraft is at least 3,000 ft. down the runway. When the following aircraft is a Category 2 (twin-engine less than 12,500 lbs), 4,500 ft. between aircraft is required. When the second airplane weighs more than 12,500 lbs., 6,000 ft. between aircraft is required. There is a similar system for landing aircraft. 

Operations on the same runway that demand wake turbulence separation equates to at least two minutes following a large or heavy aircraft. Pilots may request additional time separation, but controllers want to hear the request before a departing aircraft takes the runway. Some airports use land and hold short procedures in which case a pilot may be cleared to land on one runway to hold short of a specific intersection downfield, while another aircraft lands or departs on an intersecting runway.

Radar Separation

When operating under IFR rules, flight crews are usually unaware of the actual distances separating them from neighboring traffic. In a terminal environment, ATC is required to keep other IFR aircraft at least three miles apart. In the en route environment, that separation increases to at least five miles between aircraft. VFR aircraft will be separated from IFR aircraft by 500 ft. in Class B and Class C airspace. There are times when any of these minimums may be increased in the interest of safety. There is also a variety of different separation procedures for aircraft operating in the North Atlantic, the Pacific and the Caribbean airspace. 

Initial Departure Separation

During an IFR departure, a tower controller will separate same-type aircraft by at least one minute if their initial courses will deviate by at least 45 deg. If the same category aircraft is headed in the same direction as the one preceding but will climb through the altitude of that first departure, separation must be a minimum of three minutes.

Visual Approaches

Confusion sometimes reigns when an IFR aircraft plans to make a visual approach to an airport without an operating control tower because there is no formal missed approach procedure from a visual. If an aircraft executes a go-around for any reason at the non-controlled airport, pilots are expected to remain in that local traffic pattern and land as soon as practical. 

Contact Approaches

In some ways, a contact approach resembles a special VFR clearance for a VFR aircraft, except that contact approaches are only available to IFR aircraft and then only upon pilot request. Pilots are responsible for cloud and obstacle clearance during a contact approach even though the reported ground visibility can be as little as 1 statute mile. The airport, however, must have a functioning IFR approach procedure. 

Wake Turbulence

ATC issues wake turbulence advisories en route based on aircraft types. For example, they will likely issue wake turbulence warnings to a Cessna 182 following a Gulfstream 700. As aircraft weight increases – based on maximum gross takeoff weight – ATC might add a suffix to the aircraft call sign to alert other aircraft on the frequency.

When an aircraft weighs more than 300,000 lbs., pilots will hear ATC use the word “heavy" as in “Delta 759 heavy, turn left heading 300 and intercept the runway 27 Right localizer.” The suffix “Super” is only used when the aircraft in question is an A380-800 that weighs more than 1,234,000 lbs.  at maximum takeoff weight.

ATC will never allow a light aircraft to operate closer than eight miles to an aircraft in the super category. Visual separation on departure will also never be approved behind an A380.

Class B Services

Within the confines of Class B airspace, IFR aircraft can, of course, expect to be separated from other IFR aircraft by 3 miles or 1,000 ft. When it comes to VFR aircraft flying through Class B airspace, however, separation standards are reduced. VFR aircraft might pass as near as 1.5 nm laterally or 500 ft. vertically to aircraft weighing more than 19,000 lbs. If the IFR aircraft in question weighs less than 19,000 lbs., the 500-foot vertical separation still applies.

Laterally, however, the controller separating you vertically from a VFR aircraft is only required to ensure the two aircraft miss each other laterally. Most controllers will advise an IFR aircraft of nearby VFR traffic, of course, but be prepared that legally, that VFR aircraft might pass by pretty close.