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Garmin G3X - Indicated Engine Time vs. Total Time

C

captainrichhill

Member
For those who have been flying behind a Garmin G3X EFIS since zero hours, I'd like to gather some real world data points for the delta between displayed "Engine Time" & "Total Time."

Would you please share your current indicated "Engine Time," "Total Time" and your configuration settings? If either recording is disabled, please indicate "Disabled."

Thanks.


Engine Time?
Configured Standard RPM Value?
Disabled

Total Time?
Configured to record when?
Oil Pressure > 5PSI
RPM > 100
Airborne
Disabled
 
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RV-8; G3X; IO-360; First Flight 4/28/2022. Current engine hrs. 75.7; total hours 87.8. Do not have my other configuration parameters handy. Your results will almost certainly vary.
 
As said, I total time starts when you power up the unit and engine hours are flight hours. I have been using the Flight Log hours in my book. I think that is correct? Mine are about 40 hours apart.
 

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rockwoodrv9 said:
As said, I total time starts when you power up the unit
Click to expand...

You must have an interesting configuration... all the G3X systems I've worked with will only record Total Time when some parameter is exceeded (i.e. when the engine is running) or when the flight log timer is running. I don't know of any configuration that would cause Total Time to increment continuously when the system is simply powered on.
 
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My understanding from reading the manual is that there are two time parameters available. Engine Time which begins when the engine exceeds 100 RPMs and Total Time. Total Time can be configured a few different ways, but I was planning on using the Flight Time option. Total Time can also be based upon Oil Pressure or RPM.

I was trying to decide if I wanted a separate old school hours meter, but I think the Engine Time covers my needs.
 
Flight Timers

The behavior of both timers can be modified in the EIS settings configuration page.

Engine Time (or Tach Time) records the time the engine as running, either at a rate that varies with RPM, or at a fixed rate. If recording at a variable rate, higher RPM settings increment the timer faster, lower RPM setting increment the timer slower, based on your the RPM boundaries you enter on the configuration page. Both Fixed and Variable rate recording modes have a Minimum Recording RPM setting, below which no time will be recorded. This trigger value is entirely up to the installer to determine.
Engine Time.jpg

Total Airframe Time is more similar to a Hobbs meter. This time has a normal , fixed recording rate. The trigger for this timer to start recording can be set to RPM, Oil Pressure (Pressure > 5 PSI) or Flight Time (airborne status = in-air) .
Total AIrframe Time.jpg

Thanks,

Justin
 
mburch said:
You must have an interesting configuration... all the G3X systems I've worked with will only record Total Time when some parameter is exceeded (i.e. when the engine is running) or when the flight log timer is running. I don't know of any configuration that would cause Total Time to increment continuously when the system is simply powered on.
Click to expand...

After seeing your comment, I went and checked. I did go into my setting and and made a few changes.

Thanks for the nudge to get me to check.
 
rockwoodrv9 said:
After seeing your comment, I went and checked. I did go into my setting and and made a few changes.
Click to expand...

Still not sure what you are changing, this doesn't sound like anything I'm familiar with in the G3X configuration settings. Pictures of your Total Time and Engine Time configuration pages would help.
 
mburch said:
Still not sure what you are changing, this doesn't sound like anything I'm familiar with in the G3X configuration settings. Pictures of your Total Time and Engine Time configuration pages would help.
Click to expand...

I sent you a message from your blog. Thanks
 
For those following along at home, he was making changes to an iPad app, which has nothing to do with the engine and airframe timer configuration of the G3X system.
 
Total Time

I was also seeing my total time tracking to any time the electrical power was on. And that seemed too high based on all the time I’m spending w power on only on configuring and learning different things on the G3X and GTN.


So - Per Justin’s note I updated my total time tracking to read off oil pressure and default is any time oil pressure is over 5 PSI.

I found this option in the Configuration mode under Engine tab and settings.

Note - it was originally selected none. And I believe that’s why it was counting anytime electrical power was on.
 

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tfoster100 said:
I was also seeing my total time tracking to any time the electrical power was on....

...I found this option in the Configuration mode under Engine tab and settings.

Note - it was originally selected none. And I believe that’s why it was counting anytime electrical power was on.
Click to expand...

According to the installation manual, a setting of "None" means "Total Time is not recorded." In other words, there would be no Total Time indicated on the EFIS.

There's nothing in the manual to suggest a condition where Total Time would be recorded whenever electrical power is applied to the EFIS.


TT.jpg TT1.jpg
 
Feature request! It would be nice to be able to manually reset the times to exact numbers. I have a regular hobbs meter on my panel that I like to use for recording my flight hours, but it would be helpful to be able to double check the hobbs with the total time the G3X records (in Oil Pressure mode). Unfortunately my hobbs is persistently about 0.4 hours behind my G3X. Hobbs circuit had a blown fuse for about that amount of time.

Maybe instead I'll apply power to the hobbs for 24 minutes and synchronize them that way.
 
Now that the details have been addressed-- - what do we put for time in the log book?
 
Draker said:
Your encyclopedic knowledge of this system is astounding. Thank you again.
Click to expand...

No problem at all. I would think it's a safe bet that they made editing the time values a little more cumbersome than usual in order to prevent accidental edits from wiping out the aircraft's history. I personally once lost my recorded hours from another brand of EFIS, so I am sensitive to this! So much so that I put a mechanical Hobbs meter in my otherwise high-tech panel. :)
 
So for all of us G3X users that have not reset times, what are the factory settings for engine time and total time? In other words, how does the factory setting start engine time and how does it set total time?
 
BillL said:
Now that the details have been addressed-- - what do we put for time in the log book?
Click to expand...

Bill, good question. The short answer for me is that I add my pre and post "flying time" to my airframe time, which generally ends up with me adding .1 or .2 hours, although I've sat burning avgas for over a 1/2 hour waiting for IFR clearances... the longer version of my answer is muddled in the regulation definitions.

Here's a short refresher for everyone's edification on the nuances in regulation between Time In Service for an aircraft versus Flight Time for a pilot.

Title 14 CFR 1.1
"Flight Time means: Pilot time that commences when an aircraft moves under its own power for the purpose of flight and ends when the aircraft comes to rest after landing;" This is the time YOU log for flying. A lot of folks use Hobbs time for this, but unless the aircraft moved under it's own power for the purpose of flying as soon as the hobbs started, and the hobbs was shut off as soon as the aircraft made it's final stop...it's not accurate pilot time, albeit likely close enough for government work - your call.

"Time in service, with respect to maintenance time records, means the time from the moment an aircraft leaves the surface of the earth until it touches it at the next point of landing." This is the time logged for the aircraft

We then look to Part 91.147, which requires "The total time in service of the airframe, each engine, each propeller, and each rotor", as well as "The time since last overhaul of all items installed on the aircraft which are required to be overhauled on a specified time basis."

The Tach Time for the engine provides its TSOH, as well as for the propeller, and the flight timer keeps the TIS for the airframe (hence TTIS for the airframe). Adding the TSOH for each engine and propeller after each overhaul since new provides the Total Time In Service for those components.

Fortunately, the G3X provides the function to track both flight time and tach time, so that is how I have my times configured in the system.

It's not surprising the myriad of interpretations of "logging time" considering the multiple references and cross-references required. And we haven't discussed instrument time, pilot in command, safety pilot or second in command time - and probably others I've not thought of at this moment. oof.
 
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g3xpert said:
The behavior of both timers can be modified in the EIS settings configuration page.

Engine Time (or Tach Time) records the time the engine as running, either at a rate that varies with RPM, or at a fixed rate. If recording at a variable rate, higher RPM settings increment the timer faster, lower RPM setting increment the timer slower, based on your the RPM boundaries you enter on the configuration page. Both Fixed and Variable rate recording modes have a Minimum Recording RPM setting, below which no time will be recorded. This trigger value is entirely up to the installer to determine.
View attachment 38606

Total Airframe Time is more similar to a Hobbs meter. This time has a normal , fixed recording rate. The trigger for this timer to start recording can be set to RPM, Oil Pressure (Pressure > 5 PSI) or Flight Time (airborne status = in-air) .
View attachment 38607

Thanks,

Justin
Click to expand...

So do you use 2300 for standard recording time? Or 2700? At 2300, most of the flight (if you cruise at 2400 RPM), you’ll run the tach time faster than Hobbs..
 
Long answer . .

Taltruda said:
So do you use 2300 for standard recording time? Or 2700? At 2300, most of the flight (if you cruise at 2400 RPM), you’ll run the tach time faster than Hobbs..
Click to expand...

It depends . . . .

45 yrs ago the engine world began to gradually change. Then, it was piston speed. Intermittent was 2000 ft/min continuous was 1800 ft/min, or in the ball park. This is ~2700 and 2500 rpm for the 360 - 4.375" stroke. All diesel/natural gas industrial engines were designed and rated this way.

The hour meters were mechanical (on diesel) and gear driven, with one meter hour matching the continuous rpm. The theory is engine life, oil changes etc should be based on that point. Tach was the same way for aircraft - as I understand.

Today, there is so much better information on wear rates etc so newly designed engines don't strictly adhere to this concept, just whether it meets warranty, customer expectations and application needs/requirements.

This is the background, so with the G3X (et al) the "tach" ratios can be set by the user and operated as we see fit. I use one tach hour @2500 rpm as one actual hour.
 
My G3X "total" hours are 703.4 and "engine" hours are 579.3.

I think the 2300 and 2700 (or whatever it is) kind of makes sense because if you're running a fixed pitch prop, you'll probably cruise closer to the larger number, and if you've got constant speed you'll probably be closer to the 2300 figure.

Most people don't run CS props at 2700, and most folks with a FP prop have it pitched for cruise, which means unless you've got the power pulled WAY back, you'll be at a relatively higher RPM. At least, that's the way my plane is setup.

--Ron
 
Aren’t mechanical tachs set up for max RPM to be equal to Hobbs, and anything less than full RPM are a percentage less? Why would you want your engine time increasing faster than reality?
 
Oil pressure or flight time ?

ronrapp said:
My G3X "total" hours are 703.4 and "engine" hours are 579.3.

I think the 2300 and 2700 (or whatever it is) kind of makes sense because if you're running a fixed pitch prop, you'll probably cruise closer to the larger number, and if you've got constant speed you'll probably be closer to the 2300 figure.

Most people don't run CS props at 2700, and most folks with a FP prop have it pitched for cruise, which means unless you've got the power pulled WAY back, you'll be at a relatively higher RPM. At least, that's the way my plane is setup.

--Ron
Click to expand...

Ron was your total time set for oil pressure of flight time (Or another variable)?

Thanks
 
Anyone with a modern Ford F150 has the same issue. It counts mileage and also Engine Hours and Engine Idle Hours !
 
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