Initially, in late 2017, we had discussions with a group of light
aircraft pilots who had approached us with an idea that since phones
were now powerful computers with many sensors, perhaps there could be
an app which could make phones into an effective "Flight Data Recorder
We did some experiments with periodic in-flight upload of GPS and
sensor and audio data, including FFT analysis of the audio. We then
considered the alternative functionality of an informal "flight note"
where a "responsible person" is given notice about an impending flight
and its ETA etc.
The initial prototypes ("Flighty McFlightFace", then "SkyRunner") just
used GPS data, and would send flight status information when the pilot
requested it, direct from the phone.
Subsequent improvements simplified the pilot input, and sent emails
from our server when the device uploaded a small HTTP data packet
after a user button press action. Also, during a flight, small UDP
data packets were automatically sent to the server with position
updates from time to time, without need for user action.
At this stage some important requirements evolved:
- simple, so pilot cognitive load was low;
- data to be kept private;
- data to be persistent, so it could be a private log of recent flights;
- track map available on both device and server;
- no advertising clutter;
- no distracting push notifications;
- clarity needed with times, timezones (use intervals from start);
- should not be specific to Australian conditions;
- require as few user permissions as possible;
- very hard to accidentally start (no "pocket flights!");
- remind user if it appears that recording has been left on too long.
Then the decision was made to make the app (now renamed "TrackEcho")
suitable for other users, as well as light aircraft pilots. For
example cyclists, bush walkers.
So the app was generalised, update notes were allowed, logging was
expanded, relevant local notifications were provided, a device map was
added, with evolving track shown (and other features like saved track
overlays, interactive waypoint markers).
On the server side, provision was made for nominated persons (which we
call "trip observers"), who the user declares prior to starting a
trip, to securely access the track data in the form of a track on a
map via their web browser, and to refresh the view, to see progress in
near real time.
Finally, after thousands of test trips, mainly by the app developer
John Evershed (a keen cyclist, unicyclist and walker), and more
feedback from the group of pilots, and their aviation connections, we
have the current app, which we are proud of.