If “flight following” is a new term, don’t worry, you’re not alone. It’s not exactly a staple in many Private pilot training programs and don’t expect much attention on flight following in a checkride. But not to diminish its importance, because it’s a service that every VFR pilot should take advantage of and it could even be a lifesaver.

Flight following is a relatively simple concept – it’s an aircraft flying under VFR that is taking advantage of Air Traffic Control (ATC) services. Functionally, it indicates the flight is radar identified by ATC and a number of advisories may be available from the controller.

Some of the mystique of VFR flight following is a function of the service requiring ATC interactions which immediately invokes fear for many pilots. Because the service is provided on a workload permitting basis and involves multiple layers of service, there’s not exactly uniform delivery among Center or Approach control facilities. The combination of these realities has resulted in misinformation, misunderstandings, and even no awareness of its existence.

So what is flight following?

What we refer to as VFR flight following is largely described in AIM, 4-1-15 (Radar Traffic Information Service) which focuses on traffic advisories. ATC will serve as another set of eyes in the sky to keep you apprised of other traffic targets that could be a threat. You also gain the benefit of safety alerts from ATC.

These are alerts that can be issued by the controller for traffic, terrain or other obstructions and indicate an immediate threat. If you should hear the term “safety alert” on frequency, pay close attention and prepare to respond quickly. The red “CA” in this screen indicates a potential collision alert between the two radar-identified aircraft.

As emphasized in the AIM, and is true in practice, flight following services and advisories are provided at the controllers’ discretion, and while controllers always strive to assist participating aircraft in every way possible, their primary responsibility is separating IFR traffic. Many factors, including workload and frequency congestion, could prevent the controller from providing advisories so it should always be viewed as a supplemental tool for seeing and avoiding traffic or other obstacles.

How do I obtain flight following?

Flight following can be available anywhere radar coverage is available which is extensive even at relatively low altitudes in the east. Radar coverage is spottier in the west, but generally available at normal cruise altitudes. For low-level, terminal radar coverage, you would generally need to be operating near a Class B or C airport or Class D with terminal radar service. If in doubt, ask the local pilots about the extent of coverage in the area and even the best frequencies for requesting service.

For locating the correct frequency to request flight following, consult the Chart Supplement (A/FD) or sectional chart for published Center or Approach control frequencies. Many GPS navigators and charting apps will also provide frequency information. But remember, even with radar coverage available, flight following is only provided on a workload-permitting basis, so it’s no guarantee, but always worth the request.

What do I say to ATC?

While not intended as added pressure, suffice it to say, a controller is more likely to accept and provide services to a pilot that doesn’t sound as if they will be overly burdensome. In other words, you should strive to sound like you know what you’re doing and have some self-awareness. No, this isn’t intended to be mean or unfair, it’s simply a controller protecting their primary obligation – separating IFR traffic (not providing VFR advisories).

To help answer this important question of what information to provide and how to say it, we went to the National Air Traffic Controllers Association (NATCA) representing nearly 20,000 controllers across the country. The controller will want to know your present position, aircraft type/tail number, altitude, and your destination. There are important caveats.

If the controller is working a busy frequency, start with an initial call that provides your type/tail number and simply that you have a VFR request.

“Nashville Approach, Cessna 12345, VFR request.”

When the controller is in a position to receive a request, issue a code, and radar identify, you’re likely to hear a response similar to this:

“Cessna 12345, Nashville Approach, go ahead with your request.”

If there is some breathing room on frequency, it’s ok to minimize transmissions and provide more information in the initial call.

“Nashville Approach, Cessna 12345, three miles south of Lebanon at five-thousand, five-hundred, VFR to Greene County Airport, request flight following.”

When providing your destination, if it’s an airport located within range of that ATC facility, or a major metropolitan airport, it would be acceptable to provide the airport name or ID, but if you’re traveling a considerable distance, it’s best to stick with a major city and/or your on-course heading.

“Nashville Approach, Cessna 12345, three miles south of Lebanon at five-thousand, five-hundred VFR to Myrtle Beach, request flight following.”

If traversing multiple facilities, it may also be acceptable to request hand-offs to subsequent ATC facilities. This eliminates the need to make initial calls with all of the requisite flight information as your flight information is passed along from one controller to the next. But keep in mind, this does require a little more effort on the part of the controller. If your flight following is terminated by ATC, you can always make a new request with the next facility.

“Nashville Approach, Cessna 12345, three miles south of Lebanon at five-thousand, five-hundred VFR to Myrtle Beach, request flight following with hand-offs.”

If ATC is able to accommodate your request, your next transmission will likely be a transponder “squawk” code.   As a VFR pilot, you may have flown exclusively with your transponder code set to 1200, if given flight following, you will be asked to enter a unique code.  The controller will advise when radar contact is established. As a VFR aircraft, altitude is the pilot’s discretion unless there has been an explicit assignment by ATC for traffic purposes. You should advise the controller of any altitude changes.

“Nashville Approach, Cessna 12345, climbing VFR to seven-thousand, five-hundred.”

How is a hand-off to another ATC facility handled?

If the controller has coordinated a hand-off, meaning your flight information has been passed on to the next facility and a new controller is awaiting your check-in, the instructions will sound similar to this:

“Cessna 12345, contact Memphis Center, one-two-eight, point two-two.”

If a hand-off was not coordinated, you may be provided a suggested frequency (or not) and your current squawk code will need to be reset to VFR, 1200. You can always tell whether a hand-off has been coordinated by whether the controller’s transmission is an instruction versus a suggestion.

“Cessna 12345, radar service terminated, squawk VFR. For further flight following, suggest Memphis Center on one-two-eight, point two-two.”

What are some Do’s and Don’ts of flight following?

• DO listen up! Don’t make the controller’s job more difficult by missing your tail number on frequency.
• DO have the applicable flight plan information at the ready (airport ID, requested altitude, on-course heading, etc.)
• DO be an active participant in seeing and avoiding other air traffic.
• DO monitor the emergency frequency, 121.5 so that you may be able to render assistance to other aircraft in need and also as a backstop in case ATC has difficulty raising you on the primary frequency. Often ATC will utilize the emergency frequency as a last resort to reach you.

• DON’T be the pilot who takes 3 calls to respond. See Do #1 – listen up!
• DON’T assume ATC is taking full responsibility for other air traffic. Always watch for traffic.
• DON’T rely on ATC for navigation. You may get an inquiry if it appears you’re straying well off course, but navigation remains the pilot’s responsibility.
• DON’T rely on ATC for weather avoidance. Workload and equipment permitting, you may hear a weather advisory, but it’s completely discretionary and depends on the equipment available to the controller. You may inquire about potential weather hazards or request a frequency change to call flight service.

Does ATC consider flight following a nuisance or a bother?

To the contrary, often times an ATC facility would prefer an aircraft be on frequency as it eliminates a relative unknown (in terms of your intentions) and makes it easier for a controller to complete his primary task of separating IFR traffic. Be a good, considerate participant and you’ll get along swimmingly. 

Do I have to terminate flight following or will ATC do that?

It depends. If you’re ready to change to a local advisory frequency, you may initiate a termination of service.

“Nashville Approach, Cessna 12345, cancel radar service.”

If you need to leave the frequency briefly, you can make that request without terminating service.

“Nashville Approach, Cessna 12345, request a frequency change to call flight service.”

If you’re venturing outside of radar coverage, or if workload no longer permits flight following, it could be initiated by ATC.

“Cessna 12345, radar service terminated, squawk VFR, frequency change approved.”

What are the additional benefits of VFR flight following?

In addition to the obvious benefits of traffic advisories, safety alerts, and good situational awareness of surrounding traffic, VFR flight following can benefit you by:

• Possibility of weather advisories or obvious course deviations
• Benefits of hearing pilot reports
• Benefit of hearing general weather advisory broadcasts such as convective SIGMETS
• Practice and added confidence in interacting with ATC and listening to other communication
• Providing helpful information and assistance in the event of an emergency such as vectors to the nearest airport

If you had the choice of flying with a safety pilot or not, of course you would welcome a safety pilot. If you had the benefit of another trained aviation professional to assist you in an emergency, of course you would accept input. If you had a helping hand that could potentially provide safety alerts and even assist in weather avoidance, of course you would heed the advice. All of this and more is available to you FREE through our well-trained and capable air traffic controllers.

Download the NATCA Guide to VFR Flight Following.

I recently flew a trip from the Midwest to Reno, NV (KRNO). Reno is located in the northwest portion of the state just to the north of Lake Tahoe near the California border and on the eastern side of the Sierra Nevada Mountain range. Needless to say, it’s a gorgeous part of the world with endless recreational activities whether winter or summer or anytime in between. But the combination of high elevation and scorching hot temperatures during the summer, requires pilots to be mindful of high density altitude considerations.

High density altitude is the ultimate thief lurking in the shadows as it robs the aircraft of engine and propeller performance resulting in increased takeoff rolls and degraded climb performance. In other words, density altitude is the altitude at which the aircraft is performing. Technically speaking, density altitude is the vertical distance above sea level in the standard atmosphere at which a given density is to be found or pressure altitude corrected for nonstandard temperature. 

Density altitude is determined by first finding pressure altitude, and then correcting this altitude for nonstandard temperature variations. Air density is affected by changes in altitude, temperature, and humidity. High density altitude refers to thin air, while low density altitude refers to dense air. The conditions that result in a high density altitude are high elevations, low atmospheric pressures, high temperatures, high humidity, or some combination of these factors. Lower elevations, high atmospheric pressure, low temperatures, and low humidity are indicative of low density altitude. 

Humidity, also called relative humidity, refers to the amount of water vapor contained in the atmosphere and is expressed as a percentage of the maximum amount of water vapor the air can hold. This amount varies with temperature. Warm air holds more water vapor, while cold air holds less. Humidity alone is usually not considered an important factor in calculating density altitude and aircraft performance, but it is a contributing factor. 

As an example, consider the Reno Tahoe Airport with a field elevation of 4,044 feet MSL where the temperature is a comfortable 15 °C. Under these conditions, the density altitude is 5,416 feet. If the temperature rises to 30 °C, the density altitude increases to 7,077 feet. This means an aircraft would perform on takeoff as though the field elevation were 7,077 feet. In my particular case, this translates to a 22% increase in takeoff roll. The same scenario in a Cessna 172 Skyhawk results in a 12% increase in takeoff roll.

While many airports in areas that routinely deal with high density altitude conditions have adequate runway length for a wide variety of aircraft and conditions, you’re certainly not finished with the effects of density altitude after your ground roll. Because of the terrain surrounding the Reno Tahoe Airport, many of the published departure procedures require climb gradients of nearly 8%. In our jet aircraft, at a reduced weight, meeting those requirements were not an issue even at a temperature of 30 °C, but the calculation certainly had to be considered. And if the performance was not adequate, we would need to consider reducing weight (fuel), leaving earlier in the day with cooler temperatures or even moving the departure date.

If we go back to our Skyhawk example, at maximum weight and a temperature of 30 °C, we’re not able to achieve that type of climb gradient. Does that mean we’re grounded? Not necessarily. There are other options for departing the area including climbing above the airport until clear of obstacles, but we’d have to ensure we could do so in visual conditions. The more important point is that when we have the high elevation, high temperature (e.g. high density altitude) conditions, we must consider all aspects of aircraft performance when preparing for our flight and always have a plan. And in mountainous terrain, there’s even more to consider.