Made some KLN 94 tweaks

Hello all. I had a chance, as a result of the issues the KLN 94 GPS has been having with reading a correct OBS from the CDI to tweak some of the configuration of the KLN.

  • Hopefully fixed the issue with the CDI. Could you all monitor it to see if it’s really fixed? The issue was that the CDI’s OBS was being read as 45 degrees off by the KLN. It’s been adjusted, and let’s watch it to ensure it stays accurate.
  • QuickTune! If you search for a frequency in the KLN, you can now push it to COM 2 or NAV 2 by just moving the cursor to the frequency and pressing ENT. I can actually configure it work with COM 1, COM 2, or both. I chose to only go to COM 2 and NAV 2. This skips the step of selecting the radio to send the frequency to and also allows you to put the NAV frequency into a CDI that isn’t being used already by the GPS.
  • The connection to the KMD 550 MFD was made more robust. More information should now show up on the large moving map.
  • The configuration for the KAP 140 autopilot’s interface with the KLN 94 was improved. The autopilot should behave better now.

I hope you all enjoy the improvements. Let me know if something goes wrong or if the stuff doesn’t work like you’d want it to.

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Made some KLN 94 tweaks

Flying again, but no sender type change

Well, N194SP is flying again. It’s been way too long that the plane wasn’t flying, and for that, I apologize. This has been a painful lesson in how things work in the aviation industry. I now know what I should have done in hindsight, but each decision sure made sense when I was making them.

First, you’ll see that the fuel gauge in the plane hasn’t changed as it was supposed to. That’s because it’s flying on the Rochester part. Granted, it’s a brand new part, sourced from Air Power for $650. The CiES units and all the parts and work that go along with putting them in were going to take another month. I couldn’t afford that. So, the stock Cessna part went back in. Of course, that’s what I should have done from the first, but live and learn.

Second, I still ordered the CiES units. They’ll arrive in about a week. I don’t know how I’m going to show the level. There are three options: convert the signal to resistance and show it on the stock gauge, buy the Aerospace Logic fuel gauge for almost $1000, or get an EI CGR-30P engine monitor for $3500 (plus lots of labor). If I do anything with them, it will probably be right around annual.

So, question to my flyers: What’s an engine monitor worth to you? I’d need to add a few dollars an hour to account for the cost of the system. Is it worth that to you?

Flying again, but no sender type change

Fuel sender saga continues

I was going to wait until the issues with the fuel sender were finished to write an entry on it, but it’s going on for a very long time and people are wondering what’s up with my plane. Here’s the current story:

The right-hand fuel sender, a unit made by Rochester for Cessna, is notoriously poorly made. It’s a pretty standard unit, quite similar to one that you’d find in your car. It has a float that operates a potentiometer (variable resistor). The range is 5 ohms to 90 ohms with higher being less fuel. The pot in this design of the Rochester part is what’s known as a film pot: there’s a carbon film deposited on plastic, with a wiper that sweeps across it. The float operates the wiper. The traditional method of using windings of wire is much more durable, but also much more expensive and heavier. The quality of that carbon film is terrible and quickly wears away. This is what happened earlier, but Instrument Rebuild was able to clean it up and make it work again.

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It didn’t last. The rebuilt unit started failing at about six months time in service. It turned out that rebuilding the unit was a false economy for a rental. It may have made sense for a personally owned aircraft that didn’t fly much, but on a rental it turned out to be wasted money. It was $400 for the rebuild, and 2-4 hours of labor for each swap. When the unit failed again, I sent it to Instrument Rebuild, hoping they’d honor the warranty.

They attempted to. Unfortunately, the owner of Instrument Rebuild, Paul Malkasian, has passed away. His son, Bill, is minding the shop. Bill attempted to revive the unit, but the pot is too far gone. He’s currently attempting to get a replacement pot from Rochester, but he’s getting no response from them. He’s attempting to honor it, but it’s not working.

Meanwhile, my plane is sitting. And I am giving up on the Rochester part.

Instead, I’m replacing it with a CiES digital fuel sender. The CiES unit is half the cost of the Cessna unit ($400 vs. $800). It not a pot: it’s a magnetic sensor attached to the float. It’s sealed and enclosed. It should last longer than the plane does. It should be far more accurate than the old Cessna parts. And it’s STC’ed for 172S.

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The downside is that the plane will be in repair for a bit longer. The fuel gauge is not compatible with the digital units, so a digital fuel gauge is on order. That’s $675. Of course, I also need to replace both fuel senders, so the cost is still $800 for the senders, not just the $400 to fix one. And the kicker is that both the new gauge and the new senders are active. That means they need to be supplied with power. For the new gauge, that’s not a big deal, as it’s in the panel where power is readily available. For the new senders, it’s more of a problem, as a new wire needs to be run to each tank to supply the sender with power.

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All-in-all, it should be about 8 hours labor to get the new system in, or about $2000 total. Add to that the lost revenue from having the plane down for so long, and this has been a very expensive and hugely annoying failure. Once the CiES unit is in, though, that should be the last of these issues!

I’ll post up again when this is all resolved with the final numbers!

Fuel sender saga continues

Annual at WVFC

Yeah, I’m a bit late with this…this happened in November. It took a while to get all the information compiled, as I was new to West Valley.

In November, the plane had an annual at West Valley Flying Club’s maintenance department ahead of being placed on the line at WVFC. It was a relatively easy annual, and was done easily on time. In fact, the plane got its first renter in November, ahead of the stated on-line time of December!

As a summary, the annual inspection was $1260 for the inspection itself, plus $180 for the AD research. It was found the that Slick magnetos were due for their 500-hour inspection, which ran $360. This would be the first time the magnetos were inspected since the engine overhaul, and they needed points and new plugs. $155 put in new points, $150 put in new plugs. Of course, oil was changed during the annual, which ran $160.

The annual also found some issues at the very bottom: brakes were worn and one tire was flatspotted. $100 for a new tire and $180 to have it installed fixed one problem. $55 for brake linings and $180 for installation fixed the other problem. Also, in the process of putting it on the line, four spare quarts of oil were put in the club box in the plane for $35. All told, the process cost $2,900.

The plane spent much of November not flying due to the club move. As a result, flying hours from WVFC were only a single flight of 1.1 hours. November was definitely a losing month, but I expected that.

Annual at WVFC

Last month with Trade Winds

I’ve had one complete year with Trade Winds. In that time, N194SP has:

  • flown 299 times with
  • 82 pilots for
  • 402 Hobbs hours that resulted in
  • 275 Tach hours that consumed
  • 2,907 gallons of fuel that cost
  • $16,110 and burned
  • 20 quarts of oil and needed
  • $17,179 in repairs and
  • $3,720 in inspections.

There were zero repairs this last month with TWA, but it was only a half month and the aircraft moved to West Valley in Palo Alto, where an annual was performed. So, November does have more work than what was shown, and I’ll document that when I get the bill from WVFC.

Last month with Trade Winds

Online at WVFC!

N194SP is now ready to go at West Valley. Parked in tiedown S7, it’s available to all at West Valley checked out in 172SP.

http://www.wvfc.org/a/wvfc.org/template-2/aircraft/n194sp

The page at the WVFC website still needs some pics and the W&B link doesn’t work yet, but that’s being worked on.

Bonus: The KMD 550 is getting a database update. It hasn’t been updated in about 10 years, since the data in it is not required for flight, is expensive, and changes very infrequently. Most owners do not bother updating the 550. But… Bendix/King had the updates for half off if you also update the KLN 94 (a must for /G flight) so I went ahead and spent the $200 (+$35 tax and S&H) to get four updates through the year.

The annual itself was uneventful. A couple wear items needed help: new brake linings needed and the left main tire was flatspotted at some point. The Slick magnetos were found to be due for their 500-hour inspection, so that was also done. She’s in great shape!

Online at WVFC!

N194SP moved to PAO

Well, it happened. N194SP has served for a year at Trade Winds Aviation, but it’s now time to say goodbye to San Jose and hello to Palo Alto. West Valley Flight Club will take over management of the aircraft and it will soon be available for rent there.

The aircraft is currently conducting its annual inspection in the West Valley hangar. Once everything is up to standards, it will start flying renters. I expect that it will be available soon after Thanksgiving.

N194SP moved to PAO