ForeFlight adds new ADS-B traffic safety features

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There has been an increase in visibility on the near misses and runway incursions at airports in the first half of 2023, due in large part to social media and national news coverage of these events. Serious incidents (category A runway incursions) have trended downward in the last decade, but the overall number of incidents has risen. These have resulted from both sides of the radio in the terminal environment, attributed to both pilot error (a pilot deviation) and ATC error (an operational incident).

While it’s the commercial airline incidents that attract national attention, pilots of all airplane sizes are to blame. As pilots, it’s our natural reaction to analyze each of the cases and think how we could have avoided that circumstance if we were flying that airplane. The first thing that comes to mind for GA pilots is that when used properly, ForeFlight and Sentry can be a real help, thanks to the real-time display of ADS-B traffic in the air and on the ground. The challenge, however, is that scanning the app while flying single-pilot during takeoff or landing just isn’t practical.

The latest ForeFlight update attempts to solve this problem, by adding new “Aircraft on Runway Alerts” to better get your attention if an airplane is on the runway while you’re on final approach, or if an airplane is on short final to a runway you’re occupying. The update also adds ADS-traffic breadcrumbs, day/night overlay on maps and baro-corrected pressure altitude (finally!).

Aircraft on Runway Alerts

ForeFlight offers the most comprehensive set of safety alerts of any EFB app, and these latest runway alerts take that capability to a new level. First, you’ll need an ADS-B receiver like Sentry to take advantage of this feature, which provides a real-time ADS-B traffic feed to the app.

The first threat the system will detect is when you enter a runway (either on your own at a non-towered airport or following an ATC clearance at an airport with a tower) and there is an airplane on short final about to land. Specifically, the alert is triggered when ForeFlight detects that the airplane on final approach is within 2 NM or 1 minute from the end of the runway. You’ll receive both a visual and aural alert and the traffic will be highlighted in red. In this staged scenario, you’ll see that we taxied onto Runway 22 (we are represented by the blue dot on the ground) while N377ES was on short final:

The second threat occurs when you are on final approach, again within 2 NM or 1 minute from the end of the runway, and ForeFlight detects a traffic target occupying the runway. The traffic will be depicted in red and the aural alert will state the number of the occupied runway. In this staged scenario, you’ll see N377ES taxied out onto the active runway in front of us while we were on short final:

Both alerts are enabled by default, but you can turn either off individually in the settings section of the app. Our main takeaway after testing these alerts is that it’s critical that you pair your headset to your iPad via Bluetooth so that you can hear the accompanying aural alert. Your eyes will be and should be out the window when taxiing onto the runway or on final approach and you’ll likely miss the visual alert during these critical phases of flight if you can’t hear them.

ADS-B Traffic Breadcrumbs

The next new feature to check out in ForeFlight when flying with your ADS-B receiver is ADS-B breadcrumbs. This simple, yet powerful feature, allows you to tap on an ADS-B traffic target to view its recent flight path in green:

You can learn a lot in flight by looking up the recent flight path of ADS-B traffic, to assist with both collision avoidance and decision-making:

  • determine the runway in use at the destination airport while still 100 NM away
  • see where an airplane has been recently flying in a busy practice area
  • determine what path a nearby airplane took through an active weather system
  • see the taxi route of other airplanes on the surface of a busy airport

It’s worth noting that if you have breadcrumbs enabled for your flight path, which is also shown in green, this will temporarily turn gray when viewing other aircraft breadcrumbs. This feature requires a Pro Plus subscription.

Baro-Corrected Pressure Altitude

Prior to this update, the altimeter in ForeFlight’s attitude and synthetic vision display used GPS altitude as a source. While this is useful for general situational awareness, it can be off by several hundred feet from your actual altitude for a variety of reasons. ForeFlight solved this problem for those flying with Sentry or Stratus ADS-B receivers by using the integrated pressure altitude sensor to drive the altimeter readout in the app. It automatically corrects the raw pressure data from Sentry by taking the nearest airport’s altimeter setting from a METAR or AWOS received over ADS-B and applies the baro-correction. You’ll see the label “BARO ALT” and the current altimeter setting value displayed under the altitude tape when ForeFlight is using this source.

The end result is that you’ll now see the exact same altitude displayed in ForeFlight as on your instrument panel, provided your airplane’s altimeter is set to the same local altimeter setting. This significantly increases the utility of ForeFlight’s backup instruments and synthetic vision display, making it even more useful for instrument pilots who need to get down on the ground after a primary instrument failure in IFR conditions.

If ForeFlight does not have access to a local altimeter setting, it will automatically fall back to using GPS-sourced altitude, and display the label “GPS ALT”. You can also view the Baro Altitude in the digital map instruments, which appears on the bottom of the map when enabled.

What else is new

There’s a new option to display a day/night overlay on the maps, which allows you to quickly visualize where night has fallen around the world. This can be enabled from the Day/Night Overlay option in the Map settings:

ForeFlight currently allows Dropbox, Box and Amazon S3 accounts to connect to the app, allowing power users and organizations to better keep cloud documents organized and up to date. The latest update adds OneDrive support for Pro Plus users, which can be set up on the Documents page on ForeFlight web.

16 replies
  1. RichR
    RichR says:

    Relying on runway/short final alerts are a bad idea for the same reason you don’t use nexrad weather for real time weather avoidance…neither are “real time”. As an alert that there is at least one other acft in the vicinity, ok, but my experience in dynamic situations (in close or high closure rates) is that too often the lag is significant to cause distraction from where the target is (visual) vs where it was (ads-b hit).

    This distraction could easily result in not seeing the other traffic (looking in wrong area), or ill-advised maneuvers close to the ground trying to find the ads-b traffic. Put your eyes on where you’re going and clearing the arrival path before going belly up base turn.

    • BobR
      BobR says:

      It is a tool to provide additional information like any other tool in our electronic flight bag. You remind me of old school flight instructors that thought electronics were useless. I personally as a search & rescue pilot consider Foreflight as a mandatory piece of eqwuipment and would not fly with out it.

      • RichR
        RichR says:

        My point is not that FF traffic is a bad thing to build SA and warn you that other people are in the pattern as you approach the field, but that nuisance alerts that provide dated information are not useful when in the pattern and could actually be more dangerous as a distraction.

        • Bret Koebbe
          Bret Koebbe says:

          ADS-B traffic works differently than the ADS-B weather, which you are correct is 5 – 10 minutes old by the time you see it on your iPad or MFD. Traffic is indeed real-time, where portable and installed ADS-B receivers pick up the position and altitude data broadcast from the ADS-B out transponders of nearby aircraft.

          In the scenario we staged for this article, I was on the ground at the Clermont County Airport in a C182, where there are no ADS-B towers nearby (meaning all traffic data received is “air-to-air”). We had another C172 fly a low approach, knowing that we were going to pull out in front of them on the runway to trigger the alert shown in the article. I had a safety pilot on board to also track the airplane on final approach visually and the location/altitude shown on the iPad matched up exactly to its position in the air.

          You’re absolutely right that your eyes are your best resource for avoiding traffic conflicts (air or ground), but several of the recent incidents occurred in low IFR conditions due to circumstances beyond the pilots’ control, and these alerts would have given them advance notice of the impending threat:

    • Bob Eicholz
      Bob Eicholz says:

      “ Relying on runway/short final alerts are a bad idea”. 100% disagree. It’s a great idea and an extra safety measure. To each is own, so if you don’t like it, turn it off.

  2. RichR
    RichR says:

    My comparison to nexrad is to caution the concept of using something (ads-b) for which it may not be spec’d (in-close deconfliction). Before endorsing, I’d suggest a comprehensive test plan (e.g w/FAA, NTSB, AOPA safety foundation, etc) for ads-b performance, not just one day, one airport. I don’t doubt that FF can display its inputs, but the inputs should be validated.

    I have wasted too much time looking for residual displayed traffic to trust it in-close over visual lookout. The risk/reward balance is risking loss of control mishaps down low looking for phantom traffic vs collisions…and we know GA’s bigger risk is loss of control.

    • RichR
      RichR says:

      …and at this time it doesn’t appear that FAA endorses this type of use as it doesn’t allow its non-radar tower controllers to use it.

    • Dave T
      Dave T says:

      You are over thinking this. The feature works well. If you are on short final and get an aircraft on the runway alert, which is better? Go around if you don’t see the traffic, possibly a false alert, or land on top of the plane you can’t see because you think it’s a false alert?
      If you find you are getting too many phantom alerts (which I doubt) just disable the alerts and the rest of us will use them.

  3. Loren B
    Loren B says:

    Ironically…my sentry equipped SuperStol alerted me to “my own short final” this morning in the South Carolina low country.

    I have ADSB in/out and have had “phantom alerts” (traffic 4 o’clock 1/4 mile, same altitude) displayed on my IPad Mini several times at below 1000’ agl.

    A great new Foreflight feature…but verify and believe what your eyes are seeing.

    “Old hats” like myself are probably less susceptible to tech dependence than “children of the magenta line” IMHO.


  4. Loren B
    Loren B says:

    PS: The Sentry has consistently and accurately displayed enroute traffic…I might never have seen.

    Not sure if the “phantoms” close in are anomalies…but they are un-nerving.

  5. Michael B
    Michael B says:

    Will the Pressure Alt feature work if you have a Garmin GDL ADS-B In receiver or other Garmin equipment? Or was this only designed for Sentry equipment?

    • Rick J
      Rick J says:

      Page 282 of the Foreflight Mobile Pilot’s Guide states, “When connected to an external device that provides pressure data (such as a Sentry), the calculated barometric altitude replaces GPS altitude and a Baro Alt label is displayed below the altitude tape.”

      I won’t assume that an installed GDL or GTX3X5 passes the pressure data to Foreflight but it makes sense that it would. I won’t be able to try it myself for a couple of weeks but I’m sure someone will soon and have a more complete answer.

  6. Lee M
    Lee M says:

    All tools we are fortunate to have to be used as good judgment dictates. Best tool would be eyes out of cockpit.

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