All instruments going nuts

[JoshMan]

Hello, all. On my way from Florida to Indiana a week ago in my M20E my instruments started going crazy.  First I noticed fluctuations in airspeed indicator, VSI, altimeter, so I thought for sure I had a pitot/static issue.  Then I noticed my nav instruments going crazy as well.  I have a back up AI over on the copilot side that flipped upside down.  It is very old so very well could be going  bad.

I have flown 3 time since then and everything is still acting up.  Unfortunately cannot get the plane over to my mechanic until next week but just wondering what your guys thoughts are.  Realize it could be a number of things including grounds, static leak, shock mounts, engine mounts, unbalanced prop, etc...but wondering if anyone has ever seen this. I have not noticed any new vibrations at all.  Had a similar issue in lancair last year but did not see the fluctuations in navigation instruments.

Josh

[carusoam]

What connects those instruments to each other is the pitot static system...

When they do that wacky behavior, expect some moisture in the tubes...

Draining the moisture is pretty easy on some Mooneys... one or two push button drains.

Some older Mooneys have a dead leg in the static system that is supposed to collect moisture.

Have you drained the static system lately.  A preflight activity for Long Bodies... two buttons...

My C lived out doors. It got drained at annual...

Did it rain before this started happening?

Best regards,

-a-

 

[JoshMan]

2 minutes ago, carusoam said:

What connects those instruments to each other is the pitot static system...

When they do that wacky behavior, expect some moisture in the tubes...

Draining the moisture is pretty easy on some Mooneys... one or two push button drains.

Some older Mooneys have a dead leg in the static system that is supposed to collect moisture.

Have you drained the static system lately.  A preflight activity for Long Bodies... two buttons...

My C lived out doors. It got drained at annual...

Did it rain before this started happening?

Best regards,

-a-

 

It did rain in florida but that wouldnt make the nav instruments fluctuate like this?

[carusoam]

Two separate problems... caused by the same rain...?

-a-

[Guest]

43 minutes ago, JoshMan said:

Hello, all. On my way from Florida to Indiana a week ago in my M20E my instruments started going crazy.  First I noticed fluctuations in airspeed indicator, VSI, altimeter, so I thought for sure I had a pitot/static issue.  Then I noticed my nav instruments going crazy as well.  I have a back up AI over on the copilot side that flipped upside down.  It is very old so very well could be going  bad.

I have flown 3 time since then and everything is still acting up.  Unfortunately cannot get the plane over to my mechanic until next week but just wondering what your guys thoughts are.  Realize it could be a number of things including grounds, static leak, shock mounts, engine mounts, unbalanced prop, etc...but wondering if anyone has ever seen this. I have not noticed any new vibrations at all.  Had a similar issue in lancair last year but did not see the fluctuations in navigation instruments.

Josh

It's hard to tell from your video, but do the ASI and altimeter in the G5 do the same dance?  Water in the pitot static system would explain those, but the nav instruments are a mystery.

Clarence

[JoshMan]

Just now, M20Doc said:

It's hard to tell from your video, but do the ASI and altimeter in the G5 do the same dance?  Water in the pitot static system would explain those, but the nav instruments are a mystery.

Clarence

Clarence, the G5 is completely stable. I agree it doesnt make sense.  Just based off what I told/showed him, my mechanic was suspicious this was  related to vibration. We will see. Hopefully something simple

[Guest]

Just now, JoshMan said:

Clarence, the G5 is completely stable. I agree it doesnt make sense.  Just based off what I told/showed him, my mechanic was suspicious this was  related to vibration. We will see. Hopefully something simple

If it's something new,  a bad or broken engine mount structure might do it.  SB M 20-175 and -190 cover the mounts.

Clarence

[carusoam]

If it’s vibration caused... that's not a normal vibration issue.

What's the compass doing?

I had a broken engine mount in my M20C. There were visible air bubbles, in the compass, caused by vibration ...

Finding the broken part on mine was easy. The lower leg had two welds that fell off.  On some days the engine was hanging a little low in the opening. Other days, the engine mount was propped up by the square cube the broken welds were attached to.  It really hid the break nicely.... the engine was held nicely by 3 out of 4 small bolts...

If the vibration is only instrument panel related, and the compass is really working properly... it may be a good idea to check all the panel dampening mounts... one or two may have failed...?

PP thoughts only, not a mechanic.

Best regards,

-a-

[Jim Peace]

Did it calm down the further North you flew? Were you near the Bermuda Triangle?

[JoshMan]

It did not calm down at all. In fact i first noticed it as i was passing through georgia and has continued to act up this week. Meeting my mechanic tomorrow. Will keep you updated

Anthony now that you mention it the vertical card compass is fluctuating as well. It was just placed about 40 hours ago at annual and has really not been 100% stable since it was installed

[Shadrach]

3 hours ago, JoshMan said:

It did not calm down at all. In fact i first noticed it as i was passing through georgia and has continued to act up this week. Meeting my mechanic tomorrow. Will keep you updated

Anthony now that you mention it the vertical card compass is fluctuating as well. It was just placed about 40 hours ago at annual and has really not been 100% stable since it was installed

I think that it's coming from the motor to the mount to the steel cage structure to which the panel is attached. One of the rubber shock absorbing panel mounts could have failed, or there could be an issue causing increased vibration in the power plant. Has the spinner been off recently?  When did you notice? Did it occur suddenly or gradually? How are they at idle?...During run up?

Check that all accessories are secure before next flight and give the mount and associated rubber and fasteners a close inspection. 

[Piloto]

The alternate air valve is open.

José

[Shadrach]

45 minutes ago, Piloto said:

The alternate air valve is open.

José

Why would that cause non pitot/static instruments to oscillate?  VORs? VC compass?

[JoshMan]

1 hour ago, Shadrach said:

I think that it's coming from the motor to the mount to the steel cage structure to which the panel is attached. One of the rubber shock absorbing panel mounts could have failed, or there could be an issue causing increased vibration in the power plant. Has the spinner been off recently?  When did you notice? Did it occur suddenly or gradually? How are they at idle?...During run up?

Check that all accessories are secure before next flight and give the mount and associated rubber and fasteners a close inspection. 

It did happen suddenly. Was not there on way to florida and noticed it about halfway on my way back home

I notice it mostly at high power settings but definitely still present during run up and lower power settings.  No new vibrations to speak of. Spinner has not been off

[Shadrach]

2 hours ago, JoshMan said:

It did happen suddenly. Was not there on way to florida and noticed it about halfway on my way back home

I notice it mostly at high power settings but definitely still present during run up and lower power settings.  No new vibrations to speak of. Spinner has not been off

Right, but only when the fan is turning, correct?

[JoshMan]

49 minutes ago, Shadrach said:

Right, but only when the fan is turning, correct?

Yes

[Shadrach]

1 minute ago, JoshMan said:

Yes

So it's time to for a thorough inspection from the panel forward to the spinner.  No difference in mag drop?

[Yetti]

I vote water in the static system.  What happened when you turned the Alt Static Valve that is located under the panel, just to the left of the yoke shaft?

Did you hit the drain button?

It is possible to get way more water in the static port than will come out of the drain. Opening the battery compartment take the tube off that goes to the static ports.  with mouth air pressure blow water out.  Tape one port then the other.

[Marauder]

My vote is something broke and is causing a vibration. Since the compass is doing it, I’m thinking engine mounts or something in the path that Shadrach mentioned.


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[takair]

I’m thinking vibration.  Noe that the flag on the Nav head is also shaking.  Have you tried varying the RPM?  Agree with the others, if this started suddenly, do an inspection...

[JoshMan]

Thank you all for your thoughts.  I will update you tomorrow. Hopefully it's something simple.

Josh

Edited November 3, 2017 by JoshMan

[Shadrach]

35 minutes ago, JoshMan said:

Thank you all for your thoughts.  I will update you tomorrow. Hopefully it's something simple.

Josh

Check mag drop as well.

[JoshMan]

Just now, Shadrach said:

Check mag drop as well.

Mag drop is fine.  Like I said I have flown three times this week and plane is flying wonderful minus the instruments fluctuating.

[211º]

Do you have any old photos of your panel? It seems strange that the yoke-rod coming through the panel is not centered. If you have an old photo that shows that it used to be centered, this would cause me to think that a shock absorbing item shifted or failed in the panel mount.


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[JoshMan]

34 minutes ago, 211º said:

Do you have any old photos of your panel? It seems strange that the yoke-rod coming through the panel is not centered. If you have an old photo that shows that it used to be centered, this would cause me to think that a shock absorbing item shifted or failed in the panel mount.


Sent from my iPad using Tapatalk Pro

Interesting, 211. Here is your picture.