Shakedown cruise, let the troubleshooting begin...

[KevinR]

Hi All, 

 

I just returned from my first business trip in N252DR, a 1986 252 Rocket. She had been parked for a while before I bought her but Jimmy Garrison & Don Maxwell provided an accurate assessment of her condition. Maxwell finished an extensive annual the last week of August & the flight home from Longview TX to Ocala FL was nearly trouble-free.  Last week I made a 1700 mile trip to Columbus OH, Destin FL, then back to Ocala. A few (hopefully easily fixable) bugs appeared and I'd really appreciate a little crowd-sourced troubleshooting advice.  Here's what I found:

 

1. Panel lights, which were working, went inop. Instrument lights worked fine and so did my three flashlights that I rechecked en route when I realized the panel lights wouldn't come on.
2. EDM-700 tach wildly erratic.  Ship's tach worked fine. No sign of actual RPM fluctuation.
3. Ship's CHT gauge wildly erratic. EDM-700 CHT steady on all 6 cylinders. 
4. Occasional weak & unreadable on comm 1, a G530W.  Switched to comm 2, an old King 165, and was loud & clear. 
5. KAP 150 autopilot preferred to stay 100' below selected altitude and about 10 degrees right of selected heading.  En route GPS nav would often try to fly 10+ degrees difference between DTK and TRK. HSI was spot on during GPS approaches. 

 

I do have a digital copy of the 252 maintenance manual, parts catalog, & POH which I am happy to share with anyone if they need it to help me troubleshoot these problems :-)

 

Any advice is much appreciated- I've been out of the aviation world for a while and am thankful to find this great community on Mooneyspace.

 

Thanks!!

 

P.S. does anyone have an electric tow bar for sale?

[rocketman]

I would suggest looking for some common element to your myraid of problems, like maybe a loose ground wire

[M016576]

Those autopilot issues can be solved by using a very small screw driver and fiddling with the course tracking pots on the face plate.

Edit: the NAV mode is best suited to VOR course tracking. For best performance, I've found that the the 150 series A/P likes the APR mode for all phases of flight when tracking a GPS course. Remember, these autopilots were designed 15 years before military GPS... And about 25 yrs before the 430 came out....

[N601RX]

The tach problem is likely the sensor screwed into the incorrect hole in the mag or not screwed all the way in.  If the coaxes are long enough at the back of the radios swap them and see if it is the radio or coax/antenna.

[Marauder]

For #5 make sure the GPS (not sure if this is an option on the 530) is not in parallel mode. It will offset around 10 degrees if it is.

[John Pleisse]

Nickel and dime stuff......... If you just bought a great 252 and that's all there is, I think you have done great. What great planes they are. Did I say...."great"?

[FloridaMan]

You're in Florida. It will cost you less to fly your airplane every week than it will to not fly it. It sounds like a contact somewhere got a little fuzzy in the humidity. My #2 radio got weak and died on me once. Simply removing and plugging it back in fixed it. (for your 530, there is a tiny hole dead center at the bottom, a long allen wrench [i cannot remember the size] fits it)

 

I'd also verify that your alternator(s) is/are working. I had a lead to my regulator break on my alternator and I had the weirdest electrical issues as symptoms. 

[gsengle]

I had a similar issue flying off course when my AI started to roll over and play dead.  The plane would stay level, right of course, balanced between the dying AI and the autopilot trying to correct to stay on course...

[fantom]

Check your PM for a message about a battery powered tow I should have available soon, Kevin.

[robert7467]

Defiantly sounds like a electric power problem, check belts, ground, connections to the bus bar. I had the same erratic behavior on my Mooney and upgraded to Plane Power and problem solved.

[BobAustin]

I agree with all of the suggestions BUT...in  2 different planes with a G530 and with a G430W the old King 165 is much more sensitive and has a longer range.  Just use the 165 / 155 as your COM radio.

[robert7467]

Its amazing how many squaks you can scratch off the list by properly electrifying your plane.

[mooniac15u]

  Last week I made a 1700 mile trip to Columbus OH, Destin FL, then back to Ocala.

 

Is Columbus likely to be a frequent destination?  If so, Madison Co (KUYF) and Fairfield Co (KLHQ) tend to have the cheaper fuel in the area.

[MARZ]

For the first three I'd be looking for a loose panel ground - the isolators typically have a jumper that goes from the panel to the ship's framing.  Very possible the ground lug for the radio is tied to the panels as well.

[KevinR]

Wow- thank you all for the replies.  I will definitely investigate the grounding situation & try out the comm & autopilot suggestions.  Of note:

1. the alternator was replaced the day I picked up the airplane
2. the right mag was not grounded when I picked up the airplane.  We had to reconnect the grounding wire before the first flight. 

[KevinR]

...so here is what I found:

 

1. the autopilot does seem to like APR mode better for enroute GPS tracking.
2. panel lights mysteriously started working again, probably because the sun was up. Checked connections, nothing appeared out of sorts.
3. using the King as primary comm.  Didn't try switching the antennas yet. 

Just had a brief conversation with Don Maxwell; he called to see how everything was working post annual. He recommended I take a look at the lead running from the bottom of the left mag for the tach issue.  I'll let everyone know what I find.  

[flaflyer]

Couple weeks ago noted the 10 degree offset between heading bug and course selected, similar to what you describe. Shortly thereafter noted the A/I was listing slightly though everything else indicated straight. Was IMC at the time so turned on the Dynon and confirmed fault was the A/I. Vacuum fine. The list remained slight, less than 5 degrees. Next time I flew it (VFR), A/I obviously tilted but got better. Next time it was worse. My KI256 is now visiting Bob in Sarasota. Eagerly awaiting it's return.

[Yetti]

Check all grounds. Check and clean battery terminals/connectors with wire brush to shiny bright.  If the panel lights are on a dimmer, the dimmers get corroded/flat spots moving them back and forth should clean it up.