Answers to your questions about GPS4Flight

Why is the (Barometric) Altitude showing as 101,375ft?

If the device running GPS4Flight doesn't have a barometric pressure (altitude) function, this value is invalid, and represented by the 101,375ft value.

If the altitude is something other than 101,375, that is the correct barometric altitude according to the sensor in the device.

Does my device support Barometric Pressure?

If your device does not have a pressure sensor, the Pressurised Cabin setting will be disabled.


Besides iPhone SE, Apple’s iPhone 6 and later and iPad Air 2 and later all support measuring barometric pressure.

  • iPhone SE does not support pressure sensor

  • iPhone 6 and later support pressure sensor

  • iPad Air 2 and later support pressure sensor


It depends! There are two many devices and flavours to provide a quick answer.

An unrelated app called Usb Otg Checker can test your device to see if it supports Baromteric Pressure.

Should I enable the Barometric Pressure feature?

Short answer: If your aircraft cabin is unpressurized, Yes.

For unpressurized aircraft a barometer in the cabin pressure is close enough to actual atmospheric barometric pressure for practical purposes, but in pressurized aircraft, the device does not have access to outside pressure. Sending incorrect pressure altitude will result in incorrect calculation of relative traffic altitude.

Does GPS4Flight output (Geometric) Altitude?

Yes, if your device has a clear GPS signal, the altitude (geometric height above WGS-84 ellipsoid) will be transmitted.

Why are Destination Port and Address locked?

When the Preset Setting is set to ForeFlight, these fields are automatically set when GPS4Flight connects to Foreflight. They will be updated automatically for you to the correct values.

When in Manual mode, both these values can be modified as necessary.

My position in ForeFlight is a little blue circle!

If you are testing the GPS4Flight ↔ ForeFlight connection, and you see a flashing blue circle, rather than an aircraft icon - You are almost definitely not moving.

When your device is in motion, the aircraft icon will appear.

Why am I seeing Heading, not Course?

There are two situations where you would see Heading, rather than Course (or Track).

  1. You are on the ground, at less than take-off speed

  2. Course is unavailable for some reason. If course is unavailable, the compass in your device will be used to give you a magnetic Heading.

In flight, if your device is operating correctly, and you have good GPS fix, you should see Course (Track).

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