Warranty and Return Policy:

Flight Data Systems offers a three year warranty and a one year money back guarantee on our products.

Can I use the your products in my Certified aircraft?

The GT-50 can be used in certified aircraft.  Per this FAA Letter it can be installed in certificated non-transport aircraft. All other Flight Data Systems products do not have FAA approval for installation in certified aircraft and are intended only for Experimental/Amateur built aircraft. 

Jump to Answers for your Product:


What Apps and Devices work with the Pathfinder?

Compatible Apps:


FltPlan Go

FltPlan Go





iFly GPS

iFly GPS

WingX Pro7

WingX Pro7







Droid EFB

Droid EFB

FltPlan Go

FltPlan Go

iFly GPS

iFly GPS




Compatible Devices:

Advanced Flight Systems  5000,4000 and 3000s

Advanced Flight Systems

5000,4000 and 3000s

GRT Avionics   (Click link above for  GRT Supplement)

GRT Avionics
(Click link above for
GRT Supplement)

iFly GPS  Wifi and Serial support

iFly GPS

Wifi and Serial support

MGL Avionics

MGL Avionics



How does the Pathfinder communicate with external displays?

The Pathfinder uses Wifi to send data to your portable device and RS-232 to send data to your EFIS.

Can the Pathfinder be connected to more than one device simultaneously?

Yes, The Pathfinder can service up to Seven Wifi users.  In addition, the Pathfinder Remote can be connected simultaneously to seven Wifi users and an EFIS system.

Do I need an external antenna for the Pathfinder?

The Pathfinder has a highly sensitive built in antenna.   The Pathfinder Remote requires an external antenna.

How do I charge the Pathfinder?

Use the included USB wall charger,  your iPad wall charger, or a 2.1 Amp (or greater) car charger along with the included high current USB cable.  Use of other chargers or cables is not recommended as they can cause the Pathfinder to discharge while it appears to be charging.  

Can I use the Pathfinder at the same time that it is charging?

Yes, the Pathfinder can operate and charge simultaneously.

Will all Traffic be Displayed?

The Pathfinder is an ADS-B "in" receiver.  To receive complete traffic, you must be equipped with an ADS-B "out" transmitter (or close to an  ADS-B "out" equipped aircraft).   Non ADS-B "out" equipped traffic, not visible to ATC radar, will not be displayed.

Will the Pathfinder receive weather and traffic data outside of the United States?

No.  Only the GPS will work outside of the USA.

Is the Pathfinder a single or dual band receiver?

The Pathfinder is a single band 978MHz UAT receiver.


Will the GT-50 run down my battery?

The GT-50 should not be a significant drain on your battery. The latest GT-50 uses 0.0008 Amps when the backlight is off, an amount less than the normal discharge rate of a stored battery. Like a car's clock, it wont run down the battery.

Next time you fly, as a test, read the voltage of your battery after you land and write it down. Next, unplug the GT-50 at the rear connector.  When you return, plug in the GT-50 and read the voltage.  We suspect the voltage decrease will be the same as if the GT-50 has not been connected.

As an operational test of the GT-50, you can put an ammeter in the hot battery connection and confirm a current draw of .0008 Amps or less.

My GT-50 has No OAT Reading.

The GT-50 will not display temperature unless it sees an OAT probe connected.

Try the following test:

Unplug the GT-50 connector then take an Ohm meter and read the resistance between the green and black wires on the connector that go to the probe.  The value should be around 3K OHMS at room temperature. If the circuit is open (infinite resistance) either the wiring is bad or the OAT probe is bad.  Test the OAT probe directly by reading the resistance between the two wires coming out of the probe. Again, you should see around 3K Ohms for a good probe at room temperature.

Do you have calibration information for the GT-50?

Sorry, we can not provide calibration data for the GT-50. However you can confirm normal operation and correct calibration of the unit by:
Powering it up on a flat surface. Once it is powered up and reading "1.0", set it upside down on the same flat surface and confirm that it reads "-1.0".

Can I install the GT-50 without having to connect it to my battery?

To use the GT-50 without a hot battery connection, tie both the GT-50 power wires together (the red and yellow wires) and connect them to your instrument power bus.  Note that the clock and flight timer will be reset on each power cycle in this configuration.

How do I dim the GT-50 backlight?

The GT-50 backlight is set at a single fixed brightness. We were careful to have the backlight brightness such that it is not too bright for night operations.  We fly at night with the GT-50 often and are very sensitive to bright lights in the cockpit. We do not recommend connecting it to a dimming circuit.  Here is a comment from a customer who was concerned about the backlight brightness:

"I thought I'd write you to thank you for a superior product. I finally got around to installing one recently and am more than happy. The 'burnt orange' color is very easy on the eyes at night. Crisp and readable."

Why does the GT-50 display blank when I turn on the master switch?

The red wire of the GT-50 must be connected to the battery.  Connecting this wire to the master switch will not work.

While there is enough current on the master switch to run the GT-50 when the switch is off, the master solenoid is activated by grounding the master switch.  Once the master switch is on, there is no voltage or current on the switch.  


Fuel Return

The FC-10 is compatible with engines with a fuel return line. The flow through a second transducer is subtracted from the flow of the transducer in the fuel supply line. Order the dual sensor system.

If your engine is equipped with a fuel return line from the carburetor or fuel injection manifold back to the fuel tank you will need to install two flow transducers. One in the feed line from the fuel pump to the carburetor and one in the return line from the carburetor back to the fuel tank. This applies to certain Continental engines and Rotax 912(ULS) and 914 engines.

Gravity Feed

The FC-10 is compatible with gravity feed.  If using a gravity fed system, be sure to check your flow rate with the transducer installed by disconnecting your fuel line at the carborator and timing the filling of a gas jug.  The flow rate should exceed the max burn rate of your engine by at least 50%.  This should be done with the airplane in a climb attitude. It is also a good idea to perform this test without the transducer installed to calculate a baseline flow rate.

We now offer the FT-90 transducer which is designed specifically for gravity fed engines.  Please contact us directly when ordering to substitute this transducer for no extra charge.

Marine Use

The FC-10 can be used in a boat, however, the instrument must not be exposed to moisture as it was designed to be in dry aircraft environment.

Diesel Fuel

The FT-60 fuel flow transducer is compatible with gasoline, Av gas, diesel, jet A, kerosene and any other fluid with similar optical characteristics.

Other Sending units

We also stock the FT-90 transducer for high flow and gravity fed applications. There is no extra charge for substituting the FT-90 in place of the FT-60. Please specify when ordering. 

The FC-10 is also compatible with Floscan transducers.  You will need to figure out the Floscan model to obtain the correct K factor.  This will be a number in the thousands.  We suggest taking a picture of the transducer and documenting all numbers on the unit then contacting Floscan (206) 524-6625 x306.  

Possible Floscan models include:

201B6 .6 to 60 GPH K-Factor 29,500
231   .5 to 60 GPH K-Factor 20,000
264PB .5 to 30 GPH K-Factor 47,300

Please note we do not sell the FT-60 transducer without our FC-10 instrument. 

High Flow Readings

The system works by counting the number of rotations of a wheel inside the transducer.  Movement of the wheel by forces other than fuel passing causes high flow readings.  Suspect items are fuel pumps pulsing near the transducer and possibly excessive engine vibration.  This is a common fuel flow system issue.  If possible, run the engine without the pumps running and see if this helps. 

Possible solutions to the fuel pump pulsing issues are moving the transducer far away from the pump, installing a dampener (see link below), or isolating the transducer from strong vibrations of the engine.

Pulsation Dampener

Deviation from FT-60 Transducer Installation Instructions

We want our customers to be happy with the performance of the FC-10, therefore, we suggest following the transducer installation instructions as closely as possible for your installation. The provided instructions for installing the transducer are from Electronics International, the transducer's manufacturer.  Any deviation from their recommendations may degrade performance of the system. The only way to find out if a specific deviation will work, is to fly the plane and collect empirical data.  We have had customers deviate from the instructions successfully, but can not make any suggestions for specific deviations since every installation has many variables.

Fuel Flow Shows "0.0" When Fuel is Flowing

Perform the Following Procedure:

Test 1: With the transducer connected to the FC-10, connect a wire to the white signal wire of the transducer, power the FC-10, then rapidly tap the wire to a ground.  This simulates the normal output of the FT-60 and you should see fuel flow on the FC-10. If you see fuel flow by tapping the wire on a ground, the transducer is either jammed or has failed - Proceed to Option 1. If there is no fuel flow for Test 1, there is likely a wiring issue - Proceed to Option 2.

Option 1: (Transducer Issue) Remove the FT-60 from the fuel line and GENTLY blow (with your mouth) into the FT-60 (do not use compressed air).  You should be able to see the yellow wheel inside spinning.  If the wheel is spinning and fuel flow was indicated for Test1, the transducer has failed. The most common cause is installation in the engine compartment without insulation from heat.

If the wheel is not spinning, it may be jammed with debris.  In this case, flush the transducer with fuel in the opposite direction of normal fuel flow to clear the debris.  The best way to accomplish this is to temporarily install the transducer in the fuel line in the opposite flow direction.  Run the aircraft fuel pump to flush the transducer into a container.

Option 2: (Wiring Issue) With the FC-10 powered on and the FT-60 connected, use a voltmeter to confirm there is approximately 10 volts on the black and red wires of the FT-60 transducer.  This measurement must be taken at the transducer.

Confirm the white wire on fuel flow transducer is connected to pin 7.  Use an ohmmeter to measure between the white wire on the transducer and pin 7 on the DB-9 connector.

Proceed back to Test 1


AP-60 too quiet

To verify if the problem is with the AP-60 or the audio panel, please try the following test. 

Disconnect the output of the AP-60 at the terminal strip.  Obtain a headphone jack and wire it directly to the AP-60 output and AP-60 ground then plug in your headphones.  Power the AP-60 and the input devices and see if the volume is adequate.

System Configuration

All Com radios must be routed through the AP-60.  The output of the AP-60 must go directly to your headphones or to the radio input of an intercom.  Sending the output of the AP-60 to the audio input of your radio may not work properly and is not recommended.

Volume Control

All AP-60 channels are identical and are set at a fixed level.  Input levels should be adjusted via the volume control on each input device.

If you have an intercom, we recommend using the intercom's music input for the iPod and the intercom's radio input for the AP-60 (your comm radio should also be input into the AP-60). 

Comm Radios with Built in Intercoms

The AP-60 can be used with a radio having a built in intercom.  Wire the microphone jacks directly to the radio and the audio output of the radio to any input channel of the AP-60.  Connect the headphone jacks to the AP-60 output. The intercom function will be handled within the radio.  

AP-60 Transmit Switching

The AP-60 is capable of mixing six audio inputs.  This can include dual nav/com's.  The AP-60 does not provide switching for the transmit function, however, this can be accomplished with a simple toggle switch. Here is a transmit switching Diagram: Transmit Switching


Systems Known to Work

Slick Magnetos
Bendix Magnetos
M-14 Radial Engine Magnetos
Lightspeed Electronic Ignition
Electro Air
Rotax Four Cycle Engines (912, etc...)
Jabiru (Hardware modification required, Please contact us before ordering to have your unit modified for a Jabiru it leaves our facility)
Suzuki 6 Cylinder used in Scaled P-51
Bosch Blue Coil and 009 Distributor

Systems Known not to Work

Rotax Two Cycle Engines (582, etc...)
Two Cycle engines with 6 pulses per revolution
Fairbanks Morse Magneto
Rotec Radial Engines
Engines faster than 10,000 RPM

Other Systems

We have not tested the T-30 specifically with every ignition system, however, it accepts a wide range of signals and we believe it will work fine for most installations.   In case it is not compatible, we have a one year money back return policy.

Connecting the T-30 to Magnetos using a Resistor

Click on Image to Enlarge

First assemble the harness:

  • Break out the shield from the cable and crimp a ring terminal to the shield

  • Crimp a ring terminal onto one lead of the supplied resistor. Folding the lead in half makes the crimp more secure.

  • Solder the other end of the resistor to the center conductor (not the shield) of a 22 or 24 AWG shielded cable.

  • Cover the shield and the resistor with heat shrink

Second connect the harness to your ignition switch:

  • Screw the ring terminal with the resistor to the same screw on your ignition switch that is connected to the P-Lead of your magneto. On ignition key type switches this terminal will be labeled "L" or "R".

  • Screw the ring terminal on the shield to the ground terminal on your ignition switch.

Third connect the cable to the T-30:

  • Connect the center conductor to the yellow or black wire of the included T-30 harness.

  • The cable shield only needs to be connected on one end. Be careful not to short the shield to the center conductor.

Pulse Specifications

The T-30 will accept a pulse rate up to 230 pulses per second.  We can increase this to 400 pulses per second with a minor modification done at our facility before shipping.  

Minimum pulse duration is 320uS and an amplitude of at least 1.95V.

The T-30 settings are adjustable from 0.5 to 6.0 pulses per revolution

Tachometer Setup with one Magneto and one Lightspeed module

1) Connect the magneto only and set the associated PPR to 1.0.  Check your results.
2) Connect the Lightspeed only and set the associated PPR to 2.0.  Check your results.

Once you have verified that each system drives the tach correctly, you can proceed to connect them both at the same time with the appropriate PPR setting for each signal.  Both signals will then be monitored.

Tachometer RPM Indication Jumpy

First, determine which magneto needs attention by entering setup mode and setting the pulses per rev for one channel (left or right) to "1.0" (or as appropriate for your ignition) and the other channel to "0.0".  Set the filter to "0".  This will isolate the system to looking at only one magneto.  Run the engine.  With the filter set at "0", you should see a reading that varies +/- 20 RPM.  If it is more than this, you need to use a higher resistor value for this channel.  We suggest trying the supplied 47K resistor.  They are also available from Radio Shack. 


LC-40e Problems

1) Disconnect all wires except Power and Ground.
2) Re-connect one potentiometer to "CH1', "5V" and Ground.
3) Connect one lamp to "OUT1".

LC-40e Noise

The first place to look is at the shielding of all audio wiring.  All connections to the headphones and microphones should be via shielded wires with the shield grounded on one end. It is also advisable to isolate the mic. and phone jacks, electrically, from the airframe.


What are the mounting hole cutout sizes for the LED and Button?

LED: .323” (Lumex Part Number SSI-LXR4815IGW3B15 Datasheet)
Button: .266” (Grayhill part number 30-601 RED Datasheet)

Garmin EFIS Connection and Configuration

Screen Shot 2019-04-24 at 9.42.32 AM.png

Do I need the Button and LED

We recommend installing both the button and LED even if you have the GD-40 connected to an EFIS. The LED shows continuous status of the detector and can annunciate all test functions. The button is used for self test. Neither of these functions can be done with a connected EFIS.


Dynon EMS to L2e connection

Using the L2e with a Dynon EMS requires a custom sensor definition.  Please visit the page below for further explanation:  http://wiki.dynonavionics.com/Making_your_own_sensor_definitions

L2e sensor definition :

pins=C37_P4 C37_P6 C37_P7 C37_P8 C37_P9 C37_P10 C37_P11 C37_P12 C37_P20 C37_P21 C37_P22 C37_P23 C37_P31