What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

GRT HX slow bootup

FORANE

Well Known Member
I have a GRT HX EFIS that I installed new 2 years ago. It has the adaptive AHRS with dual AHRS option. It functions well and has never experienced issues once booted up. It does seem to be taking an increasing amount of time to erect however. It has taken so long that on some occasions I have pulled the EFIS circuit breaker and restarted it. During the bootup process I have the plane stationary with the engine running.

Ideas? Anyone else experience this?
 
GRT WS

While I do not have the HX EFIS, my WS has always been slow to boot up often taking several minutes. For comparison I also have a Dynon D10A as a backup EFIS and it?s relatively quick to boot. Fortunately, I have not noticed it taking longer as my systems age.

A while back I talked to GRT tech support about the slow boot up issue and they said I really didn?t need to wait until everything was complete but could go ahead and taxi after about 30 seconds. I?ve done this several times when others were waiting on me and haven?t experienced any system degradation. But unless I?m rushed, I usually wait until the boot is complete.
 
I have dual HX 8.4 screens with dual AHRS. AHRS 2 always takes longer to "find itself" than AHRS 1. It has always taken around 2 min, give or take a second or so. Sometimes on a hot day I would like it to go faster but it is what it is. I love everything else about the HX so I live with it.
 
We have an HX (with adaptive AHARS) mounted beside a Mini-X. The Mini is booted up and running very quickly, while the HX sits there with a blank screen for quite a while. It's not actually blank - in low light conditions one can see a very faint boot screen image displayed.

The interesting thing I see with ours is the HX comes up slowly but when it comes up it is fully ready to rock and roll, with a complete terrain view etc. Sometimes the Mini-X is "up" but still showing a black background beneath the PFD altitude/airspeed tapes by the time the HX is up and its screen is fully populated with valid data.

Oh, did I mention the GPS receiver in the Mini-X and the multi-constellation satellite receiver in the HX Adaptive AHARS are fantastically sensitive? They have no trouble acquiring position inside our metal-clad hangar with the doors closed. My poor old Garmin navigator has to be outside before it will see any satellites - not nearly as sensitive as the GRT units.
 
GRT 8.4" HX+TCW back-up Pwr.

I have been flying with dual 8.4" HX screens and dual AHRS for 7 years without back-up power and always disliked having to wait for boot-up after engine start.
About a year ago I finally decided to add a 6Amp. TCW Back-Up Pwr. System supplying power to each screen and each AHRS. Now as soon as I enter the cockpit the first switch I turn on is the TCW back-up pwr. The boot up process begins immediately and by the time I get organized with seat belts and head sets etc. the screens are fully booted with valid data from both AHRS and the EIS.
Apart from the obvious benefit of this system should you have a power failure it also enables me to start the engine without fear of the screens going dark and needing to re-boot.
This is a great system and one I feel I should have added long before I did.
 
I'll second Ivan's point. Our GRT devices are on an Essential Bus which is powered from its own battery. Flip on the ESS Battery as one is strapping into the airplane. Everything is happy long before the Master comes on, and stays happy through engine cranking, thanks to the independent ESS battery holding the ESS Bus up.
 
Backup battery is the answer!

Same here, I've always had backup and just flip on the backup switch as soon as I arrive at the hangar. By the time I am done with my preflight, it's ready to go. I start the engine with the HX's still only on backup and once the engine has settled down, I turn on the Avionics master and everything else comes alive.

Another option, if you have the GRT EIS installed in the panel, it will tell you everything you need to know about engine health in the first few minutes while you are waiting for the HX's to come on line.
 
As an alternative to a backup battery, I use the TCW power stabilizer to eliminate the EFIS brownout that occurs during start up and the long boot up wait after start. Weighs next to nothing and a breeze to install. Just another option.

Erich
 
RE: GRT Slow Boot Up

+1 on the TCW Power Stabilizer. I initially had a TCW 3A backup battery installed but forgot to turn it off or inadvertently turned it on during maintenance and as a result killed the BU battery. I replaced the BU battery with the Power Stabilizer. Like Erich says, it will keep the EFIS from resetting when the main ships battery voltage dips during an engine start. With the Power Stabiliizer, once it is installed there is nothing to remember to turn on or off and no maintenance, battery charging etc.
 
Interesting, looks like a couple of good options. Only downside I see is a slow but steady weight gain that seems to occur insidiously. Thanks for the suggestions guys.

On my last flight it seemed to boot up a fair bit faster than previously. Do you guys notice variation in bootup times or does it just seem longer on a hot day under the canopy?
 
I don?t have the newer ADHRS, but my HXr will boot in 45 seconds if the plane is very still. If wind, or I jostle around in the cockpit it takes 2 minutes and 12 seconds.
But, it hurts nothing to start taxiing after 30 to 40 seconds after power-up. All works well.
 
I have the GRT Sport HS display with the internal AHRS. The time required for the AHRS to power up and display valid attitude data takes approximately 2 minutes and is pretty consistent. I don't notice any difference based on temps. The Sport user manual in Section 8 "Limitations" states that it could take as long as 180 seconds.

With regard to having a BU battery, I think this is pretty common for EFIS systems. Dynon provides an external BU battery that connects to the Skyview display that is spec'd to keep the display operating for up to 1 hour if the the primary electrical system fails. The Skyview display monitors status of the BU battery and keeps the battery charged. GRT recommends the TCW BU battery system for their EFIS products.

Since I don't fly IFR, the TCW Power Stabilizer is adequate for my needs. For IFR a BU battery might make more sense particularly if your aircraft isn't equipped with a dual alternator electrical systems.
 
Just for fun I timed the HX and Mini-X in our aircraft... 45 seconds for the HX and 50 seconds for the Mini-X to align, providing full attitude information, as well as synthetic vision. The Mini comes up with the synthetic vision functional as soon as it has attitude info; the HX comes up with attitude then updates to show the synthetic vision view only a second or two later.
 
Back
Top