What to Expect
##############

**Enroute Flight Navigation** is compatible with practically every traffic
avoidance system on the market.  After an initial one-time setup, you can expect
that **Enroute Flight Navigation** automatically connects to your traffic data
receiver as soon as you board your aircraft, power on the avionics and go
flying. The figure :ref:`EDTFtraffic` shows what the moving map will look like
when traffic is detected.

.. _EDTFtraffic:
.. figure:: ./autogenerated/02-01-01-traffic.png
   :scale: 30 %
   :align: center
   :alt: Approaching EDTF with Traffic

   Approaching EDTF with Traffic

The figure shows two traffic factors.

- There is one aircraft in the downwind section of the traffic circuit.  The
  traffic has approximately the same altitude as the own aircraft and is
  descending.  The green color indicates "no alarm".
- There is one aircraft nearby whose precise position is unknown to the traffic
  receiver; this is often the case with traffic that has only a Mode-S
  transponder.  The traffic is most likely found within the yellow circle. The
  yellow color indicates that the traffic might be close enough to be dangerous.

The section :ref:`mainPage` covers the traffic display in detail.

.. note:: To show only relevant traffic, **Enroute Flight Navigation** will
    display traffic factors only if the vertical distance is less than 1,500 m
    and the horizontal distance less than 20 nm. Aircraft on the ground will
    not be shown at all, provided that your traffic data receiver reports the 
    flight status.


Flarmnet Data
-------------

**Enroute Flight Navigation** is able to use the database from `Flarmnet.org
<https://www.flarmnet.org/flarmnet/>`_ to identify aircraft and to show the
aircraft registration in the moving map display.  The process does not require
user interaction: once the app connects to a FLARM device and receives traffic
information, the Flarmnet database will automatically be downloaded and updated
with every map update.  If desired, the database can also be downloaded manually
on the page "Maps and Data" (open the main menu and go to "Library/Maps and
Data").


Limitations
-----------

Traffic Warnings
^^^^^^^^^^^^^^^^

**Enroute Flight Navigation** does not issue traffic warnings.  The app contains
no collision avoidance algorithms.  Color coding of traffic according to
relevance works best with FLARM devices.


Bluetooth Support
^^^^^^^^^^^^^^^^^

Quite confusingly, Bluetooth is an umbrella term for `two unrelated and
completely incompatible radio communication protocols
<https://www.bluetooth.com/learn-about-bluetooth/tech-overview/>`_ that operate
in the same frequency range.

- Bluetooth Classic, marketed under the names "Bluetooth", "Bluetooth Basic
  Rate" and "Bluetooth Enhanced Data Rate" is the standard radio protocol
  powering headphones and in-car entertainment systems.
- Bluetooth Low Energy, marketed under the names "Bluetooth", "Bluetooth LE" and
  "Bluetooth Smart" is a slower radio protocol designed for very low power
  operation and flexible network topologies.

At present, **Enroute Flight Navigation** supports only Bluetooth Classic
communication. Bluetooth Low Energy may be supported in the future if there is
sufficient demand from the user community.


Platform Support
^^^^^^^^^^^^^^^^

Access to Bluetooth radio is severely limited on iOS platforms. For that reason,
Bluetooth communication is not supported at all on iPhone or iPad devices. 

Applications are not allowed to read the Wi-Fi status on iOS platforms. For that
reason, **Enroute Flight Navigation** cannot determine the ID of the traffic
data receiver when connecting via Wi-Fi. As a result, traffic data receiver
passwords cannot be stored when using iPhone or iPad devices.