Altimeter vacilating on climb

[Leo O'Farrell]

After replacing worn and sagging shock mounts in the panel, on the first flight afterwards, the altimeter movement was abnormal in climb. The needle reached an altitude and bounced. In descent the movement seemed more normal. I must of pulled something loose.

Any suggestions? Think I'll need to get someone with pitot static test equipment to look at it, not too much room under the panel.

This is an older Cessna with a dual venturi system and instruments that seem as old as the airplane. The VSI and Airspeed seemed to be OK.

 

[Steve]

check the static hose and connection

if it's kinked or crimped it can cause erratic indications

ask me how i know

 

[WarriorPilot]

After replacing worn and sagging shock mounts in the panel, on the first flight afterwards, the altimeter movement was abnormal in climb. The needle reached an altitude and bounced. In descent the movement seemed more normal. I must of pulled something loose.

Any suggestions? Think I'll need to get someone with pitot static test equipment to look at it, not too much room under the panel.

This is an older Cessna with a dual venturi system and instruments that seem as old as the airplane. The VSI and Airspeed seemed to be OK.

You need an overhaul, the altimeter is sticking because the pinion and gears are dirty. A pitot static test will not resolve this issue.

 

[kgruber]

Yep. Time for an overhaul.

 

[pericynthion]

Hey Leo,

Did you have any luck after re-fitting that loose static connection? How did the test flight go?

Cheers
Henry

 

[flyingron]

If it's a problem with the static system, you'll often note that in addition to any jerkiness or other flakey movement of the altimeter you'll get a corresponding jerk of the VSI needle. If the VSI is rock solid while the altimeter is staggering it's most likely that instrument itself.

 

[Leo O'Farrell]

Hope this short video explains my issue. I didn't get the hose pressed on better and think I'll engage a mechanic at the field to fix the problem I caused.

I could go with what my avionics guy advised (buy a new Altimeter} and have him install it, but that's around a grand to get this done, when it's likely a disconnected or leaky hose.

 

[Leo O'Farrell]

Hey Leo,

Did you have any luck after re-fitting that loose static connection? How did the test flight go?

Cheers
Henry

All good now. Turns out I'd purchased some "super beefy" shock mounts on eBay on a recommendation. These were too strong and transmitted too much vibration. Replaced with Cessna style shock mounts (much smaller) and the issue is fixed.

 

[Let'sgoflying!]

Time to have the rotating mass balanced, then?