172SP G1000 Tach Failure Made Me Drive Back!

N521MA

N521MA

Pre-takeoff checklist
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Feb 13, 2013
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FlyBoy
Hey Everybody!
Thought I would share my little weekend story and see if any one had similar experience with G1000 Tachometer.

I invited 2 of my friends that have never been on a small plane before and figured a nice little dinner trip from KFRG (Long Island, NY) to KBED (Hanscom Field in Mass (Boston) would be a whole lots of fun.

We get to the plane (rental 172SP G1000; my Aricher III was in for maintenance so I had to rent, plus I love flying G1000, mine is 6-pack), pre-flight, startup - strange beeping noise at a rate of about 1 beep per second would not go away. No errors on PFD/MFD, volts good, no red Xs; everyting is good per checklist, yet the beeping sound (similar if don't put on your seatbelt in the car) would not go away. Tried to recycle BUS 1/2 - beeping still there. Finally, I turn off everying, BUS 1/2, Master/ALT, key completely out - restrart engine, BUS 1/2 on - beeping gone! At this poing my PAX are already scratching their head, asking are you sure we'll make it? :eek:

Depart KFRG and uneventfully get to KBED, park, ask for top off, take the courtesy car and drive to Boston downtown area for dinner (Atlantic Fish Company - probably the best breaded bowl New England Clam Chowder I've ever tried - just super good). Finally, return to the plane, 10pm, preflight, checklist, engine start, and as I try to adjust my RPMs to 1000, the next thing I know the RPM display is all over the place showing 0, 500, 1800, 300, 2200, back to 0 and ocassionally flashing red Xs. Hmm, I said to myself, I know I wasn't drinking, I hear my engine stable and sould, RPMs are definetely stable what up with that??? :confused:
I shut down, everything off, wait few seconds, startup - RPM display is good for 10 seconds and back to jumping all over the place. :yikes:

25 minutes later, plane stored for parking and we were in a rental driving back to NY for almost 5 hours, arrving this morning. Obviously, PAX were not happy with me, (1: scared of flying more than ever; 2: so much for reliable small planes, no wonder they go down every day) and hinting that maybe I am a ***** and we could have flown withing good RPM reading.

Perhaps we could and just reference airspeed, but my good old instrcutor once told me - better be on the ground wishing you were up there, than being up there wishing you were on the ground. This advise is hard to implement, but provides 100% guarantee that you will fly another day!:yes:

Sorry for long write up, but has anyone else seen RPMs display go nuts like that? Or perhaps the beeping tones?

And finally how do I make my pax assured that GA is a safe world, but crap happens here and there?
 
I've had G1000 sensors go bad as well as all kinds of steam instrumentation.

You can look in the POH and see if the tach is a go or no go item. If it is OK to fly inop, then you can make a personal go/no go.

GA aircraft have many single points of failure so maintenance issues are going to come up regardless of age.

It's disappointing, but don't let it get you down.
 
N521MA said:
....

25 minutes later, plane stored for parking and we were in a rental driving back to NY for almost 5 hours, arrving this morning. Obviously, PAX were not happy with me, (1: scared of flying more than ever; 2: so much for reliable small planes, no wonder they go down every day) and hinting that maybe I am a ***** and we could have flown withing good RPM reading.

Perhaps we could and just reference airspeed, but my good old instrcutor once told me - better be on the ground wishing you were up there, than being up there wishing you were on the ground. This advise is hard to implement, but provides 100% guarantee that you will fly another day!:yes:

....
And finally how do I make my pax assured that GA is a safe world, but crap happens here and there?
Click to expand...

Look you absolutly did the right thing. So Here is what you tell your pax.

1) The error was an indication error not a malfunction of the engine so you made the conservative and safe call to assure their safety.

2) Yes small aircraft break! Guess what so do large aircraft. Every hear of an airline cancelling a flight due to mechanical problems? Same thing.
 
Alexb2000 said:
I've had G1000 sensors go bad as well as all kinds of steam instrumentation.

You can look in the POH and see if the tach is a go or no go item. If it is OK to fly inop, then you can make a personal go/no go.

GA aircraft have many single points of failure so maintenance issues are going to come up regardless of age.

It's disappointing, but don't let it get you down.
Click to expand...

14 CFR 91.205 (b)
Visual-flight rules (day). For VFR flight during the day, the following instruments and equipment are required:

...........

(4) Tachometer for each engine.

............
Click to expand...
 
I've had a number of different G1000 quirks pop up. Some of the quirks I've seen are persistent or reappear. Knowing the airplane well so you can tell what's new versus known is valuable.

The start-up fault is one of the toughest discipline-wise as well as emotionally. But here's the thing... the fixes are often not as far away as they seem. Multiple times I've had faults happen and been fixed in under an hour. And that was starting from no idea how I was going to address the issue.

Also... not all faults require fixing away from home. I had a PTRM error one time, pulled the A/P breaker and flew home. For an AHRS failure, I just flew VFR the rest of the way back.

The two tach issues I've had (neither on G1000) were both fixed in short order... by replacing the tach hardware.
 
Still waiting on rental company to call me and let me know their verdict. They were supposed to go get it this morning and bring it back to the shop.

My money is on a faulty sensor that needs replacement.
 
Who did you rent from? Nassau Flyers?
 
So ,I take it there is no analog tach huh? Seems like maybe there should be in this particular instance.


David
 
Did the plane have recent work done on it, 100 check, annual, oil change, etc. I have a 182 with the G1000, and almost invariably after some work is done under the cowling some sensor goes bad. The things are quite fragile, and quite sensitive and when they go bad the typically give readings all over the place, or no reading at all.

In any case, you made the right decision. Your passengers should take comfort in that, and not criticize you, especially with a night flight. Personally, on a night flight I would not take off unless I knew every piece of equipment in my plane was working correctly.
 
flhrci said:
So ,I take it there is no analog tach huh? Seems like maybe there should be in this particular instance.


David
Click to expand...
No the back up instruments do not include a tach, just an altimeter, air speed indicator, and artificial horizon.
 
Not sure when exactly 100 hour was done on this one, but NFI is very strict with prompt maintenance as my plane is in the program as well and there is no funny business. Once it hits 100 hour its maintenance time no exceptions even if I need it badly; actually this is exactly why I rented this Cessna in the first place.

Still waiting to find out what happened. Will probably hear back tomorrow.
 
Would rebooting have worked maybe (not a G1000 aficionado)?
 
somorris said:
Would rebooting have worked maybe (not a G1000 aficionado)?
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If it was a sensor, no. Some of the other issues with the G1000 such as a programming bug possibly. My experience with my G1000 is that when things go wrong, rebooting typically has not helped, thought there have been some exceptions. Unfortunately, from what I have seen with my G1000, the system is so complex, that even the guys at Garmin often have problems troubleshooting it when it acts up.
 
Part of me says no problem with the flight, but them the other part has the hesitation of crossing the Long Island sound with a problem, and maybe something else failing.
 
TommyG said:
Part of me says no problem with the flight, but them the other part has the hesitation of crossing the Long Island sound with a problem, and maybe something else failing.
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Doable by just referencing airspeed - yes
Smart - probably not considering near baby IFR conditions over LI Sound, FARs and the thoughts of what else is going next?

Did I curse non-stop for 5 hours during the drive back home thinking I could have been home in bed 3 hours ago - ABSOLUTELY!!! :) LOL
 
N521MA said:
And finally how do I make my pax assured that GA is a safe world, but crap happens here and there?
Click to expand...

Even on a non-eventful flight they most likely will see and hear more than a trip made in the heavy metal. Just tell them what sounds like drama is just life.

Regarding your malfunction, I had an MP gauge read zero shortly after leaving Dallas once. I returned to the airport, spent the night in the hotel, drove home to Austin, got it fixed, drove back, then flew home. That was the right call and so was your call.

This stuff is going to happen on both new and old airplanes. Just keep going up and the good will outweigh the bad. :yesnod:
 
jesse said:
14 CFR 91.205 (b)
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"It broke after the commencement of the flight." I don't need a tach to get home. If I know my fuel flow, my MP, and airspeed, I know my power and can deduce my RPM from the tables. I can also just listen to the engine and fly my normal airspeed in a 172 or any fixed pitch plane.
 
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Henning said:
"It broke after the commencement of the flight." I don't need a tach to get home. If I know my fuel flow, my MP, and airspeed, I know my power and can deduce my RPM from the tables. I can also just listen to the engine and fly my normal airspeed in a 172 or any fixed pitch plane.
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I do not doubt you can fly the plane without the tach, however, this is a night flight, over water, with passengers(though that should not change the equation), with a malfunctioning tach for unclear reasons, that is part of the vast majority of the system that controls among other things your radios, your instruments, and your navigation equipment. Furthermore, the tach is required for legal flight. I for one see too many good reasons to cancel the flight, and not one good reason to take the chance. Just not worth it in my book.
 
Henning said:
"It broke after the commencement of the flight." I don't need a tach to get home. If I know my fuel flow, my MP, and airspeed, I know my power and can deduce my RPM from the tables. I can also just listen to the engine and fly my normal airspeed in a 172 or any fixed pitch plane.
Click to expand...

"and those instruments and items of equipment are in operable condition."

A few years ago, I made a precautionary landing due to an abnormally low oil pressure indication on the G1000. It was dipping into the red zone! (turned out the be a bad sensor).

At that time, I only had a few hours in the G1000 and was just becoming familiar with some of it's quirks, like the occasional AHRS failure (on the ground), or the Red X on the fuel guage (on the ground), until you rock the wings.

Overall, I love the G1000!

Oh by the way, I had an airline captain tell me something similar to what you said, due to the fact that the oil temp was normal. Guess what, I don't work for the airlines:rolleyes:.

I was in cruise for only fifteen or twenty mins after departing with full tanks, but I would have done the same thing had it been a low fuel warning.
 
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redtail said:
"and those instruments and items of equipment are in operable condition."

A few years ago, I made a precautionary landing due to an abnormally low oil pressure indication on the G1000. It was dipping into the red zone! (turned out the be a bad sensor).

At that time, I only had a few hours in the G1000 and was just becoming familiar with some of it's quirks, like the occasional AHRS failure (on the ground), or the Red X on the fuel guage (on the ground), until you rock the wings.

Overall, I love the G1000!

Oh by the way, I had an airline captain tell me something similar to what you said, due to the fact that the oil temp was normal. Guess what, I don't work for the airlines:rolleyes:.

I was in cruise for only fifteen or twenty mins after departing with full tanks, but I would have done the same thing had it been a low fuel warning.
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I think you and I are on the same page, and would have not flown. But to clarify, a loss of the tach is not a quirk of the G1000. The AHRS failure, and Red X on the fuel gauge which can also occur while flying are transient quirks that will appear for a few seconds and then resolve. The G1000 is by no means perfect, and I have a love hate relationship with mine.

I think for me the issue is two fold. First being familiar with the systems in the plane is real important. Second knowing when an erroneous reading is a reason to declare an emergency, scrub the flight, or make a precautionary landing. I will always err on the side of being overly cautious. I would rather regret landing the plane unnecessarily, than regret not landing the plane necessarily.
 
I've been around planes for > 30 years. Have yet to experience a mech tach actually fail completely. I'm sure it's a happened, and there are errors in them but to have one completely die on start up is amazingly rare.

Makes the 6 pack gauge set seem rather nice now that I'm hearing that the various sensors will bug out for a second or so at odd times.
 
Henning said:
"It broke after the commencement of the flight." I don't need a tach to get home. If I know my fuel flow, my MP, and airspeed, I know my power and can deduce my RPM from the tables. I can also just listen to the engine and fly my normal airspeed in a 172 or any fixed pitch plane.
Click to expand...

Do as you wish. I was simply pointing out the regulations that we're supposed to be following.
 
docmirror said:
I've been around planes for > 30 years. Have yet to experience a mech tach actually fail completely. I'm sure it's a happened, and there are errors in them but to have one completely die on start up is amazingly rare.

Makes the 6 pack gauge set seem rather nice now that I'm hearing that the various sensors will bug out for a second or so at odd times.
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There are advantages and disadvantages to both the steam gauges, and the glass cockpit. In the end I think they cancel each other out, and the decision becomes one more on personal preference than anything else. Having did my first 100 or so hours on steam gauges and my next 400 on a G1000, I am certainly not the world's foremost expert. The important thing is knowing the short comings and traps of each system and being prepare to deal with them when FUBAR occurs.
 
douglas393 said:
There are advantages and disadvantages to both the steam gauges, and the glass cockpit. In the end I think they cancel each other out, and the decision becomes one more on personal preference than anything else. Having did my first 100 or so hours on steam gauges and my next 400 on a G1000, I am certainly not the world's foremost expert. The important thing is knowing the short comings and traps of each system and being prepare to deal with them when FUBAR occurs.
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Can't disagree with anything here, just that the failure rates sound a bit skewed in favor of the mechanical systems at this point. I've had one primary instrument failure in all my years of flying and that primary instrument gave me plenty of warning before hand. I knew it was getting sketchy for a few weeks prior to it failing, and since I'm a VFR pilot with no inclination to go in the soup the instrument in question can slowly die while I saved up for repair. Even a mech tach will give notice when it's getting tired by being slow to climb up on start, or by bouncing abnormally. You did get a warning on the first run which you should have investigated before launching away from home.
 
docmirror said:
Can't disagree with anything here, just that the failure rates sound a bit skewed in favor of the mechanical systems at this point. I've had one primary instrument failure in all my years of flying and that primary instrument gave me plenty of warning before hand. I knew it was getting sketchy for a few weeks prior to it failing, and since I'm a VFR pilot with no inclination to go in the soup the instrument in question can slowly die while I saved up for repair. Even a mech tach will give notice when it's getting tired by being slow to climb up on start, or by bouncing abnormally. You did get a warning on the first run which you should have investigated before launching away from home.
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I can't think of a steam gauge instrument that I haven't seen failed at one point or another, tach included.
 
jesse said:
I can't think of a steam gauge instrument that I haven't seen failed at one point or another, tach included.
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I never said there wasn't. In fact, in prev post I said I'm sure they did fail.
 
docmirror said:
Can't disagree with anything here, just that the failure rates sound a bit skewed in favor of the mechanical systems at this point. I've had one primary instrument failure in all my years of flying and that primary instrument gave me plenty of warning before hand. I knew it was getting sketchy for a few weeks prior to it failing, and since I'm a VFR pilot with no inclination to go in the soup the instrument in question can slowly die while I saved up for repair. Even a mech tach will give notice when it's getting tired by being slow to climb up on start, or by bouncing abnormally. You did get a warning on the first run which you should have investigated before launching away from home.
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I was not the OP, but I do fly the G1000 quite regularly. The beeping noise he heard at his initial run up could actually be normal. There is a beep from the MFD when the MFD is started up after starting the engine. So I do not know if he really had any warning of an issue before launching. What I can tell you is if anything the G1000 has a way a having individual faults that occur without warning. Some of these will be immediately identifiable by some sort of error message(red X, caution warning, etc), others not so much. I have had about 5 or 6 sensors changed since I have had my plane(in about 350 or so hours). The G1000 is definitely not without its faults, nor is it trouble free. My guess is it is more expensive to maintain than a standard 6 pack, but then again it also does so much more.

If you are not familiar and comfortable with it you should not be flying it. Too many gotchas are there. Then again it is so complex, I doubt anyone knows everything it can do either. I find out new things about it all the time. Sort of like flying.
 
docmirror said:
I've been around planes for > 30 years. Have yet to experience a mech tach actually fail completely. I'm sure it's a happened, and there are errors in them but to have one completely die on start up is amazingly rare.

Makes the 6 pack gauge set seem rather nice now that I'm hearing that the various sensors will bug out for a second or so at odd times.
Click to expand...

Analog gauge and instrument systems are not immune to transient failures either.
 
Did this failure meet the criteria to report to NTSB? I'm too lazy to go look and see if the tach freaking out meets their PFD failure reporting criteria. Just one of those things I don't have to remember, not flying glass.
 
Henning said:
Analog gauge and instrument systems are not immune to transient failures either.
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One more time with vigor. I did not say anywhere that they weren't. In fact, I gave examples to that position.

Anyone else? :wink2:
 
docmirror said:
One more time with vigor. I did not say anywhere that they weren't. In fact, I gave examples to that position.

Anyone else? :wink2:
Click to expand...

Sure.

You know, steam gauges sometimes fail too? :wink2:
 
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