When it comes to knowing when to report or annoucne a distance, the advent and ever evolving integration of Global Positioning Systems (GPS) in our flying has taken a lot of the guess work out of it… But that doesn’t mean you’ll always have a GPS upon which to rely and it’s a good skill to have in your pilot’s tool bag to be able to approximate distances (and altitudes) somewhat accurately while flying.
Prior to allowing a student to fly solo, at some point during their pre-solo preparations, I require them to fly the traffic pattern with no reference to the instrument panel, completely by feel. All things being equal by the time a student is ready for solo they should know what Traffic Pattern Altitude (TPA) looks like, roughly. Various visual clues help with this, things often overlooked when flight instruments are readily available. How big are the houses when you’re 1,000 feet above the,? Where is the runway out the window on the downwind leg? Etc…
Not surprisingly finding TPA, plus or minus 200 feet and the appropriate speeds plus or minus 5-10 knots comes pretty easily for these pre-solo students who are used to flying the traffic pattern as they have recently made pattern lap after lap fine tuning their landings.
Another sample of being able to “eyeball it” is with the distance from an airport. Again, this is an approximation and it comes in handy when the control tower asks for a report at a specific distance or when approaching a nontowered airport for appropriate position advisories.
The first step is knowing the length of the runway(s) at the airport you are approaching. Let’s say the runway is about 5000’, a fairly common runway length… that’s pretty close to a nautical mile at 5,280 feet.
The next step to “eyeball-ing it” is to imagine how many of those runways you could fit between you and the approach end of the runway. Are you 2 runway lengths (approximately 2 miles) or about 5 runway lengths (approximately 5 miles) from the approach end of the runway.
This type of approximation can be very effective and is a skill that can be learned and fine tuned pretty quickly. Next time you’re approaching an airport, give it a shot. Remember to factor in the length of the runway, obviously if the runway is only 3,000 feet, 3 runways of approximate distance is closer to 2 miles than 3 miles… You can always try to guess the distance then confirm your guess with the GPS, it’s a skill worth practicing. You’ll be able to impress passengers by telling them how far away you are while gazing out the window then confirming with the GPS as opposed to searching for the distance on your panel…
Another good option is to review the chart prior to flying over a specific area and finding a couple of landmarks that are at various distances, maybe 3, 4 or 5 miles, from an airport. Being able to gauge the distance from the airport to the landmark and then compare the distance to your position from the airport or distance from the landmark you can get very close while “eyeballing” your distance.
-Fly Safe, @MTElia1B9