Avionics And Such

[Jimhamilton]

Hello Mooney Owners

Even though I am not new to aviation, I am new to aircraft ownership and am on the steep curve of learning new things I have not even thought of before. So, I have a list of questions that maybe some of you could help me with.

1. My airspeed indicator glass lens is fogged over a bit. Day flying is not a problem, however night time is a bear. Is this something I can fix as an owner or do I need to bring it to the shop?

2. My King avionics work fine, however at night when they auto dim the displays get wavy or disappear all together. All I need to do to get the display back or steady is to increase the light in the cockpit. Is their an adjustment for the auto dimming? You know, turn the brightness up a bit.

3. Some of my King avionics have scratched lens's. Can I replace these myself and if.so where do you get them?

Thanks for your replies, Jim

[Cruiser]

1, NO

2. Yes, No

3. No.

All of these require A&P involvement.

[danb35]

...and in the case of the airspeed indicator, an instrument repair station's involvement--assuming the "haze" is on the inside of the glass.  If it's on the outside, clean/polish away!

[Awful_Charlie]

Sounds like there has been a problem with damp in the aircraft.  If you haven't got it hangared, check all your covers for leaks/tears and waterproofing and make that good before you go repairing stuff, or the repairs will go the same way over time.  If you can, might be worth putting a dehumidifier in the aircraft when you park it up and get the internals all dried out.

Check your pitot and static drains too, if the fogged ASI is due to water on the inside, it has likely come in the static port, so the dehumidifier and opening the alternate static will help to reduce it, but the damage may already have been done.

Ben

[MARZ]

I had a King 155 that had a dim display - On that radio there was a pot to adjust the brightness, however it may be a sign that the display is getting weak - one other point is that the display has contacts much akin to computer memory - your dim display may be nothing more than some dampness corrosion on those contacts - a very inexpensive fix at the right avionic shop.

Lenses are available for king products - check with your repair station and see if they would replace the lens with one you supply you may avoid some mark up.

[fantom]

Quote: Awful_Charlie

....might be worth putting a dehumidifier in the aircraft when you park it up and get the internals all dried out.

Check your pitot and static drains too, if the fogged ASI is due to water on the inside, it has likely come in the static port, so the dehumidifier and opening the alternate static will help to reduce it, but the damage may already have been done.

Ben

[Hank]

Quote: Jimhamilton

1. My airspeed indicator glass lens is fogged over a bit. Day flying is not a problem, however night time is a bear. Is this something I can fix as an owner or do I need to bring it to the shop?

 

I've seen planes with some instruments that are apparently older than others. The "new" ones have nice, clear lenses, but some the lens will be a little hazy, somewhat yellow and difficult to read through. At some point, acrylic and plexi are either "old" or "UV-damaged" and will need to be replaced in order to improve the visibility. If you have a headlight restoration kit and a drill, you can try it and see if the results are satisfactory before having your A&P pull the instrument and send it off to a certified repair station. It will probably be simpler, easier and cheaper to exchange it, and that will DEFINITELY be quicker!

It all depends on what you mean by "fogged over." If it's actually moisture inside the unit, then you have two jobs--fix the ASI, then find & fix where the moisture is getting in.

[bnicolette]

At an avionics shop it seems to be about $200 per instrument to have the glass replaced.  Lower if it can just be cleaned.  I had my airspeed indicator done when I first purchased the airplane and total cost was $200 to have the instrument removed, shipped, and installed.  Not bad and it looks brand new.

[jlunseth]

Quote: maropers

I had a King 155 that had a dim display - On that radio there was a pot to adjust the brightness, however it may be a sign that the display is getting weak - one other point is that the display has contacts much akin to computer memory - your dim display may be nothing more than some dampness corrosion on those contacts - a very inexpensive fix at the right avionic shop.

Lenses are available for king products - check with your repair station and see if they would replace the lens with one you supply you may avoid some mark up.

[jetdriven]

If the airspeed needs new glass, it must be done at a repair station, and A&P can't change the glass in an instrument.Thats a repair. Call around about instrument overhauls. I have had excellent luck with Aircraft Quality Instruments in Wichita, KS. I have an AI and a DG of theirs in my panel.   Their ASI overhaul is 115$:  http://www.flyaqi.com/pressure.htm

Now, regarding KX-155 display lenses, they get old, and bleached from the sun. A hangar fairy, or an owner under A&P supervision could remove the face plate with 4 screws, and replace the lenses in a few minutes. They are held in place iwth a dab of silicone. Lenses from here, 114$ a side:  http://www.chiefaircraft.com/hw-088-0863-01.html 

discussion about the subject:  http://www.beechtalk.com/forums/viewtopic.php?f=21&t=52746

 

[Jimhamilton]

Thanks to everyone. Your ideas and experience are just what I needed, God Bless, Jim

[Jimhamilton]

Thanks to everyone. Your ideas and experience are just what I needed, God Bless, Jim