Aritifcial Horizon slow

simtech

simtech

En-Route
Joined
Aug 15, 2012
Messages
3,122
Location
mississippi
Display Name
Simtech
Home Airfield
KGTR
On my last two flights AH would take a while for it to come up. On first start up it would be stable rather quickly. But after I shut down and say wait 2 hours and get back in it, it would stay collapsed for about 15 minutes before it came back. Vacuum gauge showed 5.1 so its not vacuum and the DG works fine. Is it on the way out the door? Once it comes back online it works fine but Im not trusting it in IMC at this point. I may just get a new one come my annual in april. This just started too.

edit..I may start with a new filter, but the DG is working fine if they happen to share the same filter.
 
Last edited:
You've pretty well answered your own question. If you don't trust i, get it overhauled or replace it.
 
Just finished replacing, overhauling EVERY vacuum components in a 182 doing the same thing. Sent the AH out for overhaul/repair and the report back was the instrument was filled with "gunk". Seems the hoses were degraded internally and basically destroyed all the other vacuum components. The pump was bad and the vacuum relief valve filter crumbled in my hand. Just changing the main filter is not enough. Some of these hoses and components were original circa 1975.

Check your hoses and replace if old.
 
Perhaps rather than the expense of a complete overhaul, send it to a shop that will do an inspect, repair as needed. Savey Mechanic had an article on this very subject in AVweb. Cost $250 for the repair vs. $900 for the overhaul.
 
The vacuum pump was replaced a few years ago before I purchased the plane. I hope the filters were changed then. Ill check everything in the system though for peace of mind. Ive never heard of one failing like mine after the first start. Usually you hear it is slow to come up when cold not warm. Oh well..it will be taken care of.

I like savvy, especially his repair on condition not a number. With that said, my mag had 900 hours on it and it failed on me away from home. So..hahaha I wished it was done at 500 hours, because then I likely would not have had to leave my plane and go back a week later for it.
 
Morgan3820 said:
Perhaps rather than the expense of a complete overhaul, send it to a shop that will do an inspect, repair as needed. Savey Mechanic had an article on this very subject in AVweb. Cost $250 for the repair vs. $900 for the overhaul.
Click to expand...

????

You can buy a new horizon for under $1000.

OP...are you sure your Artificial Horizon is getting slow or is the real one getting fast? It's likely ramping up for the leap forward this weekend? :rolleyes:
 
simtech said:
On my last two flights AH would take a while for it to come up. On first start up it would be stable rather quickly. But after I shut down and say wait 2 hours and get back in it, it would stay collapsed for about 15 minutes before it came back. Vacuum gauge showed 5.1 so its not vacuum and the DG works fine. Is it on the way out the door? Once it comes back online it works fine but Im not trusting it in IMC at this point. I may just get a new one come my annual in april. This just started too.

edit..I may start with a new filter, but the DG is working fine if they happen to share the same filter.
Click to expand...

Start with the new filter, it never hurts and is cheap, and if you were a good boy last year maybe the maintenance fairy will grant you a miracle.:lol:

If you weren't a good boy, well, you'll probably have to follow up with an overhaul, it sounds like it's dying.
 
simtech said:
The vacuum pump was replaced a few years ago before I purchased the plane. I hope the filters were changed then. Ill check everything in the system though for peace of mind. Ive never heard of one failing like mine after the first start. Usually you hear it is slow to come up when cold not warm. Oh well..it will be taken care of.

I like savvy, especially his repair on condition not a number. With that said, my mag had 900 hours on it and it failed on me away from home. So..hahaha I wished it was done at 500 hours, because then I likely would not have had to leave my plane and go back a week later for it.
Click to expand...

The thing about running on condition that Mike doesn't really get into is that you have to put real effort into tracking condition so you catch things before they fail. If you are going to operate a 500hr mag past 500hrs 'on condition', well, now you have to open it up periodically, inspect the points, the gears, the bearings, the contacts, clean it out, and put it back in service to establish that it is still in good condition. I would think every 50hrs/Annual, whichever comes first, would be sufficient to keep you within pre-500 hr reliability rates. Points are a PM item to me, because bad points have multiple bad effects, including bad effect on the coil. How the points look also tell you how the condenser and coil are doing.

Running 'on condition' and 'running to failure' are both viable resource management techniques, but they are not the same, and running to failure leaves you in a bind more often.
 
mondtster said:
I'd be willing to bet that the prices used in the article being referred to were doctored to make the repair avenue sound more enticing. :rolleyes:
Click to expand...

Naahhhhhh...Mike surely wouldn't do that...would he? :rolleyes:
 
simtech said:
On my last two flights AH would take a while for it to come up. On first start up it would be stable rather quickly. But after I shut down and say wait 2 hours and get back in it, it would stay collapsed for about 15 minutes before it came back. Vacuum gauge showed 5.1 so its not vacuum and the DG works fine. Is it on the way out the door? Once it comes back online it works fine but Im not trusting it in IMC at this point. I may just get a new one come my annual in april. This just started too.

edit..I may start with a new filter, but the DG is working fine if they happen to share the same filter.
Click to expand...

Probably a dumb question here but whats the OAT or temperature where the plane is sitting?

I noticed on a few planes I fly here in michigan they are fine coming out of the hanger but when I park them outside for a few hours the AH takes about 10 minutes to come fully up.
 
MyassisDragon said:
Probably a dumb question here but whats the OAT or temperature where the plane is sitting?

I noticed on a few planes I fly here in michigan they are fine coming out of the hanger but when I park them outside for a few hours the AH takes about 10 minutes to come fully up.
Click to expand...


its been in the 40's full sun the last few times. The first time I noticed it the plane was shut down for only 20 minutes when it did it.
 
MD11Pilot said:
Just finished replacing, overhauling EVERY vacuum components in a 182 doing the same thing. Sent the AH out for overhaul/repair and the report back was the instrument was filled with "gunk". Seems the hoses were degraded internally and basically destroyed all the other vacuum components. The pump was bad and the vacuum relief valve filter crumbled in my hand. Just changing the main filter is not enough. Some of these hoses and components were original circa 1975.

Check your hoses and replace if old.
Click to expand...

That is an excellent point about the hoses. If a deteriorating hose is what clogged up this one, then it will kill a new one quickly as well. Nothing lasts forever, including hoses. The vacuum hoses are usually pretty easy to change.
 
Like the others said, work you way through the system, how's hour vacuum reading? Filters, preheat (just like a engine, your panel should be preheated in cold ops).

All else fails Kelly aerospace will overhaul it, complete with new bearings for about $300
 
If it acts drunk and won't stabilized if you tap it then the gimble is most likely shot.

We had one that was on it last legs but you could hit the panel above it to jar it into working.
 
Just another "story - albeit this one is true". I flew for a commuter airline many years ago that operated Twin Otters. Overheard a fellow pilot call in and ask Maintenance to meet him at the plane. Said he saw something strange inside the AH? Mechanic looked and told the pilot " I don't see anything" so crew took off and flew their trip. All was well until the next to last leg when he saw it again and called in. This time he reported a cockroach sitting on the airplane symbol but again it "escaped". During the next leg the roach got caught in the spinning gears and let's just say that roach guts and the inside of an artificial horizon do not mix well. Interesting write up!
 
You must log in or register to reply here.
Back
Top