Aspen acting very strange. Any thoughts?

Salty

Salty

Touchdown! Greaser!
PoA Supporter
Joined
Dec 21, 2016
Messages
14,237
Location
FL
Display Name
Display name:
Salty
Took three flights today, full shutdown and power up of all equipment each time. The Aspen was miscalculating the winds by about 50 knots. It caused the HSI to show my heading incorrectly by close to 30 degrees. There was a stiff headwind this morning, but it was closer to 40 than 90…. You can see there’s about a 27 knot difference between TAS and GS, so it’s probably closer to 60 knots off.

Any clues what the heck could cause this?

5E87B54D-A926-4851-9CD8-46BEE01550C4.jpeg
 
Do you think the 50 F is accurate? If warmer than actual that would cause the computer to compute an higher than actual TAS.
 
Last edited:
Yeah it would be accurate
 
My view out the windshield was easily 20 degrees off from the hsi
 
We just went through another issue with our Aspen PFD… In case this helps (caveat: your issue might be same or might be a different cause)

Started when we Had an avionics shop check the Airspeed indication. In our case the Aspen airspeed was significantly wrong. Shop tried to adjust it but it was out of adjustment range. It was not a leak in the Pitot system, but incorrect indication from the Aspen itself. Apparently a common failure mode on the old Aspens that the (?) sensor board (?) fails.

Cost to fix was so much, that it made send to upgrade to an Aspen “Pro Max” instead (with trade-in credit deal from Aspen). Been very happy with the replacement EFD1000Pro MAX.

edit to add:
Looking at your picture, your problem might be differ t: it might be your heading sensor (should be a flux gate compass sensor somewhere maybe in one wing?), I think that incorrect sensor would cause a heading variation, like you are seeing.
 
IAS on the aspen below 130 is within a few knots. I have a tendency to cross check in the pattern with the steam asi so I’d notice if it was way off.
 
You can’t quite see the ias on the steam gauge in the pic, but it can’t be off 5 knots by the look of it.
 
Yeah in second thought, check your heading / compass sensor that is feeding your Aspen.

keep in mind that it’s trying to solve the “wind triangle” using your heading, airspeed, and (?) maybe ground track from GPS ?.

So an Incorrect heading indication with always cause it to think you have a strong crosswind (eg it incorrectly thinks you are flying with a crab angle).

(disclaimer: I’m not an Aspen dealer, just someone who flies with an Aspen).
 
ChopAndDrop said:
Yeah in second thought, check your heading / compass sensor that is feeding your Aspen.

keep in mind that it’s trying to solve the “wind triangle” using your heading, airspeed, and (?) maybe ground track from GPS ?.

So an Incorrect heading indication with always cause it to think you have a strong crosswind (eg it incorrectly thinks you are flying with a crab angle).

(disclaimer: I’m not an Aspen dealer, just someone who flies with an Aspen).
Click to expand...
I have no idea how to check that. Isn’t it an aspen module?
 
This exceeds my knowledge, so the most honest answer I can give you is “I don’t know” … at this point would consult an avionics shop (an Aspen dealer) for help tracking it down.

I’ll leave you with this other cautionary tale:
At first sign of trouble with our Aspen, we took ours to a local avionics shop but they were not an Aspen dealer. They fooled around and charged me ~4 hours of labor to say “yeah it’s broke, better take it to an Aspen dealer to do anymore”. Not a good use of their time, or my money.

I should have taken it to an avionics shop that had the correct Aspen systems knowledge and the diagnostics tools, first.
 
Actually, I forgot I snapped a pic of my compass at the same time as that pic, and I was heading 330. So it was 30 degrees off.
 
ChopAndDrop said:
fyi, More info here, on compass sensor for Aspen:

https://mooneyspace.com/topic/33816-aspen-efd-1000-heading-error/
Click to expand...
Awesome. Thanks!


This quote is interesting as this was a dog rescue flight and I had 3 large wire crates in the plane.

It can be affected by cargo loading creating a local magnetic field. My sensor is installed above the hat rack. On one flight I had a long metal piece that extended into the hat rack. About 30 degrees of heading error. Of course I didn’t catch this in the preflight so completed a long flight with the error. My first indication was that there seems to be a really strong cross wind that was not predicted
Click to expand...
 
Did it line up with the compass on the ground?
 
Jim K said:
Did it line up with the compass on the ground?
Click to expand...
I think so, but I’m embarrassed to say I don’t know. It was a severe clear day and I don’t remember specifically checking on the ground. I first noticed the problem while I was still over the runway, but not on the ground.
 
I just went out and tested it on the ground and it matches the compass. Unfortunately, I’ve already removed the crates and replaced the seats….
 
Sounds like it needs a test flight!
 
This morning the wife said she wanted to go up tomorrow. Later this afternoon she was freaking herself out by thinking too much about it. So *maybe* she'll go with me tomorrow AM for a test flight.... cross your fingers.
 
Take a look and see if you can find where the magnetometer is installed. If it's in the tail, you'll probably be more susceptible to magnetic interference caused by ferrous metal in the fuselage.
 
eman1200 said:
(BIG RED X)
Click to expand...
So far, I've had more and worse issues with the Aspen than I did with the G5's, and I've flown with the g5s about 15 times longer. This is making me really re-consider investing more in Aspen rather than just switching to Garmin.
 
Last edited:
Salty said:
So far, I've had more and worse issues with the Aspen than I did with the G5's, and I've flown with them about 15 times longer. This is making me really consider investing more in Aspen rather than switching to Garmin.
Click to expand...
What kind of screens do they have in the aspen?
 
Test flight today with seats in and no cages it worked properly. I guess I set it back up in that configuration and see if it happens again.
 
Last edited:
Confirmed. I put the wire crates back in and am getting a 28 degree error on the heading. It’s odd though, I don’t think there’s a magnetometer anywhere near them, but I haven’t found where it’s installed yet.
 
Salty said:
Confirmed. I put the wire crates back in and am getting a 28 degree error on the heading. It’s odd though, I don’t think there’s a magnetometer anywhere near them, but I haven’t found where it’s installed yet.
Click to expand...
Factory position (for the original king hsi system) is in the left wingtip. When they put my g5 in, the new one went in the tail on a newly installed shelf a little past halfway back. I wonder if yours isn't on the factory avionics shelf right behind the baggage compartment. Take the hatch out of the rear bulkhead and have a look. I would guess an avionics shop could move it further into the tail if that's the issue.
 
It’s definitely not in the tailcone. It seems to only be the largest crate, so either it’s being up higher matters or the crate itself picked up some polarity. I think it’s the later because if I put the crate in the other direction the error shifts toward the opposite pole.
 
Can you demagnitize the crate in question?
 
should'a bought a mooney, sheesh.........
 
Salty said:
This morning the wife said she wanted to go up tomorrow. Later this afternoon she was freaking herself out by thinking too much about it. So *maybe* she'll go with me tomorrow AM for a test flight.... cross your fingers.
Click to expand...
Is this going to be her 'get back on the horse' flight? A Test flight might not be the best agenda for that.
 
Salty said:
Confirmed. I put the wire crates back in and am getting a 28 degree error on the heading. It’s odd though, I don’t think there’s a magnetometer anywhere near them, but I haven’t found where it’s installed yet.
Click to expand...
The one in my Cardinal was out yonder in one of the wings. I was shopping Grummans once and the subject came up about putting one in. Avionics dude said they put them in the fuselage on those and it can be kinda tweaky.
 
Maybe it was the dog

dog-dressed-as-knight-picture-id164142782
 
ChopAndDrop said:
We just went through another issue with our Aspen PFD… In case this helps (caveat: your issue might be same or might be a different cause)

Started when we Had an avionics shop check the Airspeed indication. In our case the Aspen airspeed was significantly wrong. Shop tried to adjust it but it was out of adjustment range. It was not a leak in the Pitot system, but incorrect indication from the Aspen itself. Apparently a common failure mode on the old Aspens that the (?) sensor board (?) fails.

Cost to fix was so much, that it made send to upgrade to an Aspen “Pro Max” instead (with trade-in credit deal from Aspen). Been very happy with the replacement EFD1000Pro MAX.

edit to add:
Looking at your picture, your problem might be differ t: it might be your heading sensor (should be a flux gate compass sensor somewhere maybe in one wing?), I think that incorrect sensor would cause a heading variation, like you are seeing.
Click to expand...

Was yours indicating a non zero airspeed on the ground?
 
You must log in or register to reply here.
Back
Top