Narrative:

While in cruise flight as part of a flight of two aircraft in loose formation; on a direct route from ZZZ; main instrument display; dynon EFIS-D100 failed going blank resulting in loss of multiple flight instruments including airspeed; altitude; magnetic compass; turn rate; slip/skid ball; bank and vertical speed. I attempted to reset the system first by resetting the circuit breaker and then by cycling the avionics power with no joy. Backup ahrs was available via an ipad running foreflight with a stratus 2.given the location over mountainous terrain and a strong tailwind; I elected to continue the flight west to clear the mountains in excellent VMC with the aircraft in loose formation validating altitude and airspeed data. The flight terminated uneventfully at ZZZ1 without ever recovering the D-100. This aircraft is equipped with both a D-100 and a D-120 which gives the illusion of redundancy; however once the D-100 went down; all ahrs information was lost on the D-120 as well even though engine information continued to display.the combination of foreflight and the stratus 2 with full ahrs turned out to be an excellent and reliable backup with very accurate altitude and groundspeed information provided; though I will be having a backup system installed to provide full redundancy for airspeed and barometric altitude.

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Original NASA ASRS Text

Title: Kitfox pilot in formation flight reported primary instrument failure over mountainous terrain. Pilot used electronic flight bag as a backup navigation device.

Narrative: While in cruise flight as part of a flight of two aircraft in loose formation; on a direct route from ZZZ; main instrument display; Dynon EFIS-D100 failed going blank resulting in loss of multiple flight instruments including airspeed; altitude; magnetic compass; turn rate; slip/skid ball; bank and vertical speed. I attempted to reset the system first by resetting the circuit breaker and then by cycling the avionics power with no joy. Backup AHRS was available via an iPad running ForeFlight with a Stratus 2.Given the location over mountainous terrain and a strong tailwind; I elected to continue the flight west to clear the mountains in excellent VMC with the aircraft in loose formation validating altitude and airspeed data. The flight terminated uneventfully at ZZZ1 without ever recovering the D-100. This aircraft is equipped with both a D-100 and a D-120 which gives the illusion of redundancy; however once the D-100 went down; all AHRS information was lost on the D-120 as well even though engine information continued to display.The combination of ForeFlight and the Stratus 2 with full AHRS turned out to be an excellent and reliable backup with very accurate altitude and groundspeed information provided; though I will be having a backup system installed to provide full redundancy for airspeed and barometric altitude.

Data retrieved from NASA's ASRS site and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.