Fixing an Hydraulic Leak in the Gear System!

The day after Kathy and I returned from Virginia, I noticed a small pool of hydraulic fluid on the hangar floor under the aircraft.  It was clearly coming from the belly area that housed the gear operating system.  A quick check of the hydraulic fluid reservoir showed the level had dropped substantially since it was checked at the annual inspection a month ago.  Oh oh!

I had two immediate thoughts.  One: crap.  This is the reason why a lot of pilots stick with fixed landing gear.  Retractable gear is complex (especially on Cessnas) and some feel the additional speed gain is not worth the extra cost in maintenance.  Now that I've made my bed (by buying a retractable), I have
to sleep in it!

The second thought was:  this needs to be fixed asap.  One of the big issues with Cessna retractables is the problem with hydraulic leaks.  There are no uplocks on Cessna gear, it's held up with hydraulic pressure.  If a line or fitting should fail in flight, the hydraulic pump would pump all the fluid overboard and there would be no way to get the gear down.  The standby pump needs fluid to work and of course, there wouldn't be any.  Thus, a bent metal landing is guaranteed.

So the first thing to do was try and find out where the leak was coming from.  I removed the back seat and opened the access panel that covered the gear actuators.  There was red fluid on the belly panel under the right gear actuator and the aft end of the actuator was slightly wet with fluid.  Nothing was seeping or dripping even though there is always pressure in the lines (even when the plane is parked in the hangar).

I pulled up the hydraulic schematic in the Service Manual on my phone (doesn't everyone have this handy?) and studied it as I really did not fully understand how the system worked.  It was apparent that the DOWN side of the system is pressured when the gear is down (obviously) and the UP side is pressurized when the gear is up, but of course this can only happen when the plane is flying (or up on jacks).

So I surmised that the leak might be in the UP system and not the down.  How to check that?  Go flying!!  So that's what I did.  I left the access panel off so I could see the actuator when I turned around in my seat.  I took off, raised the gear and climbed to 2500 feet.  Once I had leveled off, I looked back and...ah ha!!!... I saw a small line of red fluid running forward on the floor from the aft end of the actuator!

Back on the ground, I got out my borescope and had a closer look.  There were only two places the leak could be coming from--the threaded cap (or "gland" that the parts diagram calls it) or the AN elbow fitting in the centre of the cap (where the UP pressure line connects).  There was no way to tell which was the guilty party.

I gave my mechanic Chris a call and he agreed that I could bring the plane over to his hangar for him to have a look.  After recounting my story, he agreed with my diagnosis and said the actuator needed to come out so we could have a closer look.

An hour later the actuator was out of the plane and apart on the bench.  It looked to be in good shape.  The 3 O rings and their retaining rings looked fine.  There was no scoring in the cylinder bore and all the parts moved as they should.  Hmmm.  I was hoping to find that the O ring on the gland fitting had been damaged in some way but other than a slight flattening, it looked ok.  Chris said that the fluid might have been getting by it regardless.

I asked about the AN fitting and Chris said it looked fine and that these fittings rarely leaked (famous last words).  So we left it undisturbed.

Actuator on the bench.  The gold "gland" fitting on top
and the blue AN fitting in the centre. 

The actuator was then reassembled (with new O rings) and installed back in the plane.  Again, about a 1 hour job.  The a/c had been hoisted on jacks, so Chris turned on the master switch.  The hydraulic pump ran for about 5 seconds as it filled up the actuator.  He then moved the gear lever to UP and  the wheels swung up into the fuselage.  All good so far.

He then took a mirror to the back of the actuator and oh! oh!, fluid was weeping out of the AN fitting!!  Darn!!  So that was the problem after all!!

To make a long story short, the actuator came back out so we could access the faulty fitting.  A new O ring was fitted to the fitting, everything was reinstalled and the gear swung once more.  And...NO LEAKS!!  Finally!!

So the moral of the story is:  DO THE EASY STUFF FIRST!!  We should have jacked the plane, swung the gear and looked for the the leak in real time.  Unfortunately, we were both convinced that something in the actuator itself had failed and it needed to come out!  The good news is that I now have a fully overhauled right MLG actuator so it shouldn't need any attention for, hopefully, a very long time!!!

 

A Very Mechanically Satisfying Day

 As some of you may know, I maintain a couple of blogs.  The most popular is the one about our flying adventures in C-GDKX.  The other one deals with operating and maintenance issues--this one.

I haven't written anything here for quite a while but since I had a very satisfying day--mechanically speaking, that is--I decided I would write it up.  Kind of a log of "owner performed maintenance", for the record.

At the last annual in May, Chris my AME (who's an awesome mechanic) noted an item on the snag list-- "alternator noise suppressor loose"--but elected not to fix it.  When I mentioned it to him, he said that the noise suppressor didn't really do anything and it wasn't worth his time to pull off the alternator to fix it.  He said he just turned it to tighten it as best he could and left it like that.

I felt it myself and sure enough, it was slightly loose.  There was no danger of it coming off as it had turned to the point that it was impacting the alternator bracket and couldn't move any further.  So no safety issues.

Still, I didn't like the idea of something loose under the hood, so to speak.

Interestingly, several months ago, the radio started making occasional static noises.  It seemed to happen only on take-off and disappeared once level in cruise.  It wasn't a big problem as you could still hear transmissions through the static, but it was annoying.

A little more diagnosis revealed that it only happened under full throttle and disappeared when the throttle was reduced.  Hmmm.  The engine vibration is highest at full throttle, I wonder if a lose wire is  vibrating and creating the static...what a minute...could be the loose noise suppressor?!!!

With that revelation I was now fully motivated to pull off the alternator and tighten the suppressor to see if that would fix the problem.

Now I need to mention that in a car, removing an alternator is no big deal.  You simply unbolt it, loosen the belt, unplug a single connector and remove it.  But light aircraft alternators are dinosaurs.  In fact the alternator on my plane is the same as on a 1960's Ford.  Instead of a single plug, there are seven--count them--seven wires that connect to three separate posts.  Three on the BAT terminal, one the FIELD terminal and three on the GND terminal.  In addition, all these wires are jammed into a tiny space between the back of the alternator and the front baffle on the engine.

A quick snap of all the wires so I could remember 

how to reconnect them.  Broken ground wire is top left.

I've had the alternator off before (actually to install the noise filter back in the day) and it's not a fun process.  The wires are old and brittle and you have to be super careful not to break anything.  But I figured the benefits outweighed the risks, so decided to plow ahead.

I got everything off ok and was able to tighten the suppressor.  I used a couple of drops of Locktite this time to make sure things stayed put.

Then is was time to reconnect everything.  It did not go well. 

I simply couldn't get the nut back on the BAT post no matter how hard I tried.  There was so little room I had to use a screwdriver to push back the rubber cover and simultaneously push down the wire terminals.  I pushed harder and suddenly--snap!!!!--oh *&^*^*!!!  I had broken the wire that connects the wire shield to ground.  

And to make matters worse, the shield wire was already short and there was not enough wire left to simply reconnect another ring terminal.

I'm so snookered, I thought.  I'm in way over my head and will need to get Chris to bail me out.  So cap in hand I drove over to Chris's shop.  He was crazy busy with airplanes lined up out the door.  There was no way I was going to get him to drop what he was doing to help me.  I would have to get in the queue.  It might be days, maybe even a week before he could help me.

However, he was kind enough to listen to my predicament about the broken ground wire.  Some mechanics would berate you for screwing up but Chris was totally cool.  He quickly said:  "That's not a big deal.  That wire you broke runs up to the voltage regulator on the firewall and the factory put a service loop in the wire when it was installed.  You just need to pull some more of the wire down to the alternator and you're in business.  I've done it myself many times."

Yippee!!  I felt SO much better!  Not just because he told me the solution, but it was his trust in me that I could to it that was incredibly gratifying and a huge boost to my confidence.

So after gathering the appropriate tools, I went back to the plane and slowly and methodically repaired each of the wires, reconnected everything and reinstalled the alternator.

I pulled the plane out of the hangar and with some trepidation, started the engine, half expecting several circuit breakers to blow!  Thankfully, everything was nominal, so I taxied to the runway, did my runup (all normal) and took off.

And in the full power climb to altitude??!!!!  NO STATIC ON THE RADIO!!!  WHOO HOO!!!  FIXED!!!!!

Now in closing, I need to say to those of you who are not mechanically inclined, this story may sound like much ado about nothing.  "You just fixed a broken wire!  What's the big deal!"'  And you're probably right.  But you've no idea of the incredible satisfaction it gives when you correctly diagnose a problem (especially an aircraft electrical problem) and then fix it yourself--particularly when you initially felt the fix was way beyond your pay grade--yet you managed to do it.

It was, I said at the top, a very mechanically satisfying day.  

 

 

Got Word From the Engine Shop--It Was All My Fault

Got the definitive word from the engine shop that repaired my cylinders. 

They said the issues were caused by too high temperatures, probably from over aggressive leaning.  There was no evidence of damage caused by detonation (thankfully) .  That then discounts the original theory that it was the bad gas from Costco that was the problem.  It wasn't.

I never could fully understand the rationale, although at the time, it seemed as good a reason as any.  But I was confused with the fact that a) the rpm's increased dramatically when I leaned in flight and b) the plugs were totally sooted up when I pulled them.  Both facts point to an overly rich mixture which in fact, cools the cylinder and serves to prevent detonation.

Ok, so that's settled.

I must confess that I am now totally gun shy of screwing up my engine again.  My theory that it's impossible to over lean a 150 HP O-320 has been blown to bits.

So what to do?

The answer is to bolt on engine instrumentation and monitor the heck out of it.  That means multi-cylinder probes for both CHT and EGT with built in alarming if things go south.

The good news is that there are a number of relatively low cost, digital engine monitoring solutions out there.  After some research, I settled on Insight Avionics, a Canadian company based in Fort Erie.  They have a nice little system called the G2 that was designed for planes like mine.  It also includes a fuel flow monitor/totalizer which will be really useful.

I got a hold of them and was pleasantly surprised that due to the pandemic they were offering some amazing deals, specifically dealer pricing and the Canadian dollar at par (their price list is in US dollars).  Yippee!  I placed an order right away.  Cost will be somewhere around $2K CDN and it will arrive next week.  As before, I hope to do the installation myself under Chris' supervision.

So what about the engine and the cylinders?  Well, let me fill you in...

Aerotec, the engine shop in Halifax did a great job with the cylinders.  They had them cleaned up, valves and seats ground and lapped, painted and shipped in a couple of days.  Chris called me to say the cylinders had arrived at his hangar and we could start the installation the next day.

There was only one problem.  One was missing.

Whaaaat?

Yup.  FedEx had screwed up.  They only delivered three and the fourth had been returned to the depot in Barrie. Great.  After calling customer support, they assured me it would be on the truck the next day.

Chris had already booked space in his hangar, so we started on the install of the first three.  It went quite well.  But as I've said before, sometimes it's better not being part of a major overhaul.  There are so many moving parts in an engine and you kind of freak out realizing how many things could break.

A top overhaul, or replacing all the cylinders, is like open heart surgery on an engine. Everything in the engine is opened up.  It's all there in plain sight--crankshaft, cam shaft, pistons and connecting rods--all open and swinging in the wind.

As I watched Chris work, I realized just how much I depended on him and his skill in putting everything back together.  He literally had my life and the life of my passengers in his hands.

The second thing I realized was what an amazing thing an internal combustion engine is.   Yet, we so easily take them for granted.  Even though this engine had been designed way back in the 1950's, it was an amazing piece of machinery. 

As Chris held each cylinder up to the engine block, I pushed the wrist pins through the piston and connecting rod securing them together. Chris then pushed the whole assembly up flush with the case and bolted it down.

What struck me was how beautifully machined each of the components were.  The tolerances were perfect and the pins slid smoothly in on a film of oil with absolutely zero play or wiggle.

It reminded me of a quote by Stephen Coonts in his book The Cannibal Queen when he was doing a pre-purchase inspection of the Stearman: 

"The engine...ah, that big, round 9 cylinder radial is a work of art...a film of oil on the pushrod bushings and on the bottom of the cowling...I reached in and got some on my fingers and felt that feeling of good, clean oil against precision machined steel."

Exactly.

So what about the missing cylinder?  Well, it didn't show up the next day either.  We had 3 and 1 installed, but number 4 was next and it was missing.  Fortunately, it was also time for the plane's annual inspection so Chris put the install on hold and went to work on that while I went looking for the missing cylinder.

Fedex customer support, probably located in Thailand or something, was only marginally helpful.  Yes, the cylinder hadn't been delivered either day.  Yes, it should be on the truck the next day.  No, they had no way of knowing that for sure. And yes, there was no way of knowing for sure if the cylinder was in Barrie, Tuktoyaktuk or Thailand.  

Great.

So with Chris' $90/hour shop rate multiplying in my head, I did the only thing I could do.  I got up at the crack of dawn the next day and parked myself at the door of the Fedex Ground Facility in Barrie.  Hoping against hope the cylinder was still in there somewhere.

To paraphrase the old Birk's advert:  "Happiness comes in a Lycoming brown box.'

It was!  So to make a long story short, I drove the missing cylinder to the hangar and Chris had everything back together before the end of the day.  After a through going over, we moved the plane outside of the hangar and fired it up.

It started instantly and ran beautifully.  Hurray!  It was time to start the break-in procedure for the new jugs and that will be the subject of my next post.

Needless to say, it was wonderful to have a healthy running airplane again.

   

I Now Know What Happened--Detonation Cooked My Engine

I think I know what happened.

I had a chat with Chris, my AME this morning.  About the low compressions and the leaky exhaust valves.  I rehearsed the whole story to him.  Told him how confused I was about what had caused it.

He sat quietly for a moment and then said:  "I think it was the bad gas".

"How so?"  I said, "All it did was carbon up my plugs.  I changed to avgas and everything was fine."

"I don't think so", he said.  "Some bad things happened to your engine while you were running on that Costco gas."  He explained:

"Typically bad gas is low in octane and octane is what prevents detonation in your engine.  Most people think octane in fuel is a performance enhancer  but in reality, it's a performance reducer.   It prevents the gas exploding instantaneously and allows a controlled burning of the fuel/air mixture which is key to smooth and safe engine operation.

People think the gas explodes in the combustion chamber when the spark plug fires.  But it doesn't.  It actually takes several millseconds to burn and it's the progressive energy from that combustion event that forces the piston down smoothly on the power stroke.

If the gas was to explode, in say a few microseconds, the piston would still be on the way up and the resulting heat and shock waves will seriously damage the piston and valves.  That instantaneous explosion is called detonation and it's a very bad thing."

"My sense", said Chris, "is that while you were flying around trying to sort out what was wrong with your plane, you were subjecting the engine to a prolonged period of detonation.  That detonation drove up the cylinder head temps beyond the allowed limit and damaged the components inside.  And since you don't have a cylinder head temp gauge, you were blissfully unaware of what was going on."

Oh my.  I felt sick to my stomach but knew instinctively that Chris was right.   It was all my fault.

Now, the big question was:  just how bad was it going to be?

With my permission, Chris went to work and started dissembling the engine with a view to removing the number two cylinder which had the worst compression.  I couldn't believe how fast he worked.  He had the cylinder off and on the bench in what seemed only a few minutes.  Clearly, he had done this before.

No. 2 cylinder removed.  Connecting rod and big end clearly visible

We peered anxiously into the cylinder head.  At first glance, things seemed to be fine.  No scoring on the barrel.  The valves were where they were supposed to be and neither appeared to be damaged.  The smaller one, the exhaust valve, had a pinkish hue to it which Chris said was evidence of heat distress.

Chris pushed out the valves and we had a look at the valve seats.  Oh, oh.  Both valve seats were badly pitted all around their circumference.  The exhaust valve itself had a noticeable groove worn around it.  It was obvious that neither valve was sealing properly.

Chris explained that the high temperatures had softened the metal of the valves and their seats and both had started to erode under the continuous heat and pounding of the detonation event.

I was aghast.  So there was my poor engine, its components and valves screaming in anguish, helplessly beating themselves to death, while I sat idly by at the controls!  The more I thought about it, the more I felt like crying!

Pulling myself together (well, not really, it's only a machine after all.  Or is it?), Chris and I had a long chat.  He said that it could have been a lot worse.  The cylinder clearly needed to be repaired, but the rest of the engine appeared to be fine.  The key question was just how bad were the other cylinders?

Cost was going to be a big factor.  A new cylinder assembly from Lycoming, factoring in the horrible US exchange rate, was about $2700 CDN.  Add in GST, say $3000 a pop.  So $12K for parts.  Plus labour, say $15K total.  Crazy.  More than half the cost of a new engine!!

I started having trouble breathing.

The other option was to repair the cylinders.  Regrind the seats and valves.  New guides. Clean everything up and reinstall.  Chris said to expect around $1.2K per cylinder.  Not great, but a lot better than buying new.

Suddenly, in a rare flash of brilliance, I suggested we call Jason Crowell, the President of AeroTech Engines in Halifax whose firm had built the engine 5 years ago.  Perhaps he could provide some insight.

So we did.  And Jason was fantastic.  It's his company's name on the engine and I know he takes great pride in his work.  After listening patiently (with me fully expecting him to scream at me for running Costco gas in his precious engine), he offered to do the cylinder work for us.  He recommended pulling all the cylinders just to be safe because we didn't know how much damage had been done to the other three cylinders.

Timidly, almost afraid to ask, I said how much to do all four?  To my surprise and everlasting joy, he said no more than $500 each and maybe less if they were all like #2.  Whoo hoo!!

So that's what we did.  Chris pulled the rest of cylinders yesterday and boxed them up.  I picked them up this morning and delivered them to FedEx in Barrie for shipment to Halifax.  They should get there by the end of the week.

DKX, sans cylinders, is now back in my hangar awaiting its renaissance.  The engine looks so weird.  You can see right through to daylight on the other side!  Check out the pic below.

And never, I mean never, show this picture to my wife.

Stay tuned for the rebuild, hopefully within a couple of weeks!!

It Happened. The Big $$$ One. Now What?

I'm still in shock.

Got some bad news today.  Low compressions on all 4 cylinders.  All 4 exhaust valves are leaking.  One really badly.  Worst case--complete top overhaul.  Huge $$$'s.  After only 600 hours on the engine.  I still can't believe it.

Paradoxically, I was just re-reading a blog from a couple of years ago, where I was musing that in 28 years of aircraft ownership, I've never experienced "the big one", i.e., a completely unforeseen and hugely expensive maintenance issue.

Well, that all changed this morning.

In my last post, I talked about the bad Costco gas and how I thought that had fixed the engine roughness that I had experienced in flight.  I really thought it had.  But during subsequent flights, I could sense that something was still amiss--the engine just didn't feel right.  It seemed fine in the climb and at cruise, but there was a disconcerting low vibration at lower rpm, particularly noticeable when I reduced power when turning base.  Something wasn't right.

A further clue was a noticeable "softness" in one cylinder when I pulled the prop through by hand.  I had had this happen before, but it went away after several more hours of flying.  This time, even after multiple flights, it was still there.  Hmmm.

Last week, Jim, the guy who has a Thorp T-18 in the hangar next to mine, came by and I asked his opinion.  Jim is a true homebuilder, super experienced, very technical and an engineer's engineer.  He pulled the prop through and frowned:  "Yeah, you got a soft cylinder all right.  I've got a compression testing rig at home.  Why don't we meet next Saturday and I'll check all four cylinders for you."

That was this morning.  I drove to the airport with a gnawing sense of dread in my gut.  Hoping it wouldn't be that bad.  Maybe just the one cylinder.  Maybe a simple stuck valve.  Maybe an easy fix.

Nope.  Compressions were:  #1--70/80, #2--40/80, #3--low 60's, #4--low 60's.  #1 was passable, but the rest were horrible, especially #2 where the air hissing out the exhaust pipe was clearly audible.

Complete and utter bummer.

But why?  How?  A relatively new engine.  Flown regularly.  Never abused.  Lots of x-country time.  My last two engines went well past TBO.  I hadn't changed anything in my technique of engine management.

Car gas?  But I had run both of the previous engines on car gas.

Costco gas?  Poor gas quality leading to valve failure?  Maybe a remote possibility.  But I've got to believe that the bad gas incident was a one off.  Maybe a couple of jerry cans worth.  This was a five years in the making problem.

Too aggressive leaning?  This is the red herring that often gets blamed for burnt valves.  But I've scrupulously followed the POH guidelines--lean slowly to the first sign of roughness, then richen back to smooth engine operation.

Now having said that, and thinking back to the previous engines, I used to run them richer.  My mechanic at the time, Frank DeJong, warned me about leaning too much so I'd only lean to peak rpm and then add back in a couple of clicks for good measure.  Clearly running rich of peak (ROP).

But today's thinking says that running lean of peak or LOP is good for the engine.  As long as the cylinder head temps don't get too high, it actually produces cleaner combustion and stops the valve guides from getting fouled with the byproducts of incomplete combustion.  Or so the thinking goes.

Could I have inadvertently over temped the engine and smoked the valves?  I don't have a cylinder head temperature (CHT) gauge.  No C172 does.  They aren't considered necessary.  But could my little bit of extra leaning have pooched the engine??!!!!!!

Again, conventional wisdom says that the Lycoming 0-320 is such a small, de-tuned, low compression engine that it's virtually impossible to hurt it by over leaning.

At the end of the day, who the *(^%$%  knows for sure?

Jim said that it was weird that all 4 exhaust valves were leaking.  Usually, it's just one cylinder that goes bad.  Could it have been a bad batch of valve guides from the factory?  Improper machining of the valve seats?  Bad exhaust valves from Lycoming's supplier?

Clearly at some point, I will need to have a conversation with Jason, the president of AeroTech, the firm that overhauled the engine 5 years ago.  He's a nice guy and there maybe something he can do from a warranty standpoint, but I will need to have all my facts straight first.

Next steps?  A borescope exam of each cylinder to see what's really going on in there.  Hopefully Chris my mechanic will do that next week.

Stay tuned. 

And if you're feeling charitable, please go ahead and start a "Go Fund Me" campaign for my poor, ailing exhaust valves.  They're gonna need it.

Bad Gas. I'm Never Going to Costco Again!!

A few weeks ago when I was up for a local flight, the engine began to run slightly rough.  At first, I thought it was my imagination, but as I flew along, it actually stumbled for a nano second and my adrenaline spiked.  Steve Coonts in his book The Cannibal Queen calls it a "lummer--a shot of cold urine to the heart".  Urine, adrenaline--same concept I guess.

Anyway, it certainly got my attention.  I peeled off back toward the airport and on the way checked the mixture and mags.  The mags were fine, but as I leaned the mixture, the power climbed quite a bit more than usual before it fell off.  Normally during leaning at cruise, the power moves slightly higher, then drops off as the mixture moves lean of peak.  In this case, it climbed.  A lot.  Hmmmm.  Symptomatic of an overly rich mixture??

When I got back on the ground, everything seemed fine during taxi.  But I felt that the engine was running a bit rough at idle.  Or was it my imagination again?

Back in the hangar, I decided to have a look at the plugs.  Their colour is generally a good indication of the state of the mixture.  White or light grey means too lean, light brown is good, dark brown or black is too rich.

I unscrewed the #1 cylinder lower plug  and had a look.  It was soot black!  Not just black in colour, but coated in black soot!  What the ^&%&????  That could be big trouble!!  A stuck valve?  Blocked air intake?  Who knows, but clearly that cylinder was in trouble!

I unscrewed the #2 plug.  Same thing!!  #3 and #4 were also the same!  Soot black.

Ok.  So it wasn't a single cylinder problem.  It had to be carburation.  I checked the air filter.  Clean. No obvious blockages in the intake system.  Hmmm.  Time to talk to Chris my AME.

Chris said yes, it could be a carburetor problem and it might need to be overhauled.  But with only 600 hours on the engine that seemed unlikely.  But he was super busy and couldn't get to the plane for several weeks.  Great.

And then he asked:  "You run car gas right?"  I said yes, most of the time.  He asked: "Where do you get it".  I told him Costco.  I use their premium which doesn't have any ethanol.

He said:  "I remember a fellow a while back who got a load of bad car gas from somewhere and it made his engine run really roughly.  He switched back to avgas and it smoothed out immediately."

OH REALLY??!!!

That was enough for me to hear!  I headed back over to the plane and immediately drained out the gas into several jerry cans.  I then taxied (still seemingly running roughly) over to the airport gas pumps and filled the tanks with 100LL.  At $2.18 per litre it cost over $300!!  Still if that fixes it, it would be worth every penny!

I fired up the plane.  It  ran roughly for a minute or so and then noticeably smoothed out!!  Whoo Hoo!  That was the freaking problem!!

I took the plane flying and it ran normally.  After landing I pulled the plugs.  They were now perfect!  A nice light brown.  No soot at all.  Thank you Lord!!!

Needless to say, that was the last time I bought gas at Costco!   Clearly, the price of their premium gas was attractive, often 20 to 30 cents less than the name brand guys.  But definitely a bad idea.

After checking around on the internet, I determined that Shell Premium had a reputation of being the best quality gas available.

Needless to say, that's where I'll be going from now on!!

Christmas Came Early--Installation of an IFR Certified GPS Navigator!

When pilots upgrade their panels, particularly with equipment used for serious IFR flying, they generally take their plane to an avionics shop.  A week later they show up and fly away with the new gear installed, certified airworthy by a professional shop and generally functioning as expected.  A very large cheque is usually written at some point in the process.

As I noted previously, I always wanted to have a certified GPS navigator in my plane, particularly now that I had an upgraded panel and a digital autopilot.   Clearly, the ideal time to install a new navigator was when I had the panel opened up for the ADS-B install.

However, the cost of certified boxes, e.g., the Garmin GTN series, were big bucks, and would cost more than half the cost of the entire airplane to supply and install.  Way out of reach for this budget minded aviator.  So at the time, I reluctantly said no to a new panel mounted GPS.

That was Feb. 2019.  Later in April at Sun and Fun, true to form, Garmin announced a brand new, low cost GPS navigator, the GPS 175.  Cost?  $4000US!!  I couldn't believe it!  If only....

Regardless, I planned to order one later in the year and make it my winter project to install it.  And that's what I did.

I again sourced the unit from Dave at Eagle Aircraft in Parry Sound and he did up the wiring harness as before.  The harness is pretty simple--power, ground and 3 serial ports to interface with the autopilot, Aera 660 portable and the GTN 225 radio.  Also included was another GPS WAAS antenna and coax.  Unfortunately, I couldn't use the GPS antenna already installed for ADS-B.  As I mentioned previously, it's ok to take the GPS signal from the navigator to the transponder, but not ok to do it the other way round.

The big decision was how to organize the new panel.  In lieu of a panel mounted navigator, I had mounted the Aera 660 portable in an AirGizmos dock at the top of the panel.

The Previous Panel after the ADS-B Install

Clearly, the portable needed to come out of the panel but the 4" whole it left was too large for the 2" GPS 175 to go back into.  Hmmmm.

It looked like everything would have to be moved up.  Plus, convention put the audio panel at the top of the stack (which I had ignored previously).  So it would be, from top to bottom:  audio panel, new navigator, #1 Comm, #2 Comm and transponder.

And yes, you guessed it--all the trays (which, if you read the previous post, were a royal pain to install) would have to all be moved...again.

One of my concerns with moving the trays was having to drill even more holes in the instrument frame.  The plane is 46 years old and has had a variety of radios over the years.  The frame on both sides looks like swiss cheese from all the drilled holes.  Fortunately, the floating nut plates that are used to secure the trays are quite robust and should still work ok.

Once the new navigator arrived, I moved the plane into Chris, my mechanic's hangar, and got to work.  I was amazed at how fast I was able to progress.  Clearly, my trial and error experience with the whole ADS-B installation was paying off.

Trays Arranged and Re-installed

I had the panel stripped down pretty quickly and pulled out the radios and trays.  My technique of stacking the trays with the radios installed on the bench and then making two drilling template went perfectly.  I had the new holes drilled and the trays reinstalled in one day!  The wiring harness went in and I was able to connect everything together the next day, as well as configure the units.

Chris came over, had a look at everything and told me I had made "a very clean installation".  Whoo hoo!

I went flying the next day and was completely blown away by the amazing capabilities provided by the new navigator.

I took off and headed east climbing to 3500 feet.  I pushed the "Procedure" button on the 175 and loaded in the RNAV 31 approach at Edenvale, using SIGLI as the Initial Approach Fix.  I turned the autopilot to GPSS mode and punched "Activate" on the 175, then put my hands in my lap and watched the magic.

The plane turned to a perfect 45 degree intercept to capture the track and then proceeded to follow the approach course complete with perfect turn anticipation to intercept the waypoints.  As the plane turned 90 degrees to intercept the final approach course, the navigator flipped from TERM (Terminal mode) to LPV (Localizer Performance with Vertical navigation) mode.  The autopilot switched to ARM and the glideslope jumped to the top of the CDI.

As we proceeded along the final approach course at 3500 feet, the glide slope slowly came down on the CDI.  Once it hit centre, the flag flipped to CPL (Coupled), the nose dropped and the plane started down, following the profile to the airport.  All I had to do was adjust the throttle to maintain 80 kts, tweek the trim and lower the flaps.  We flew right down to 200 foot minimums (in clear weather of course!).

Once we hit the MAP (Missed Approach Point), I initiated a full power climb for the overshoot.  The 175 then navigated us to the MAHP (Missed Approach Hold Point), made a perfect direct entry into the hold and flew several perfect, wind corrected ovals around the holding fix!!  Absolutely amazing!!

Needless to say, I continue to have fun with my new toys.  Regrettably, my instrument rating needs to be renewed so I can't legally file IFR, but I sure can fly a lot of approaches in clear weather.

Once this COVID-19 thing winds down, I'm hoping the social distancing rules will be relaxed and I can, once again, fly with an instructor and ultimately with a pilot examiner to pass my IPC (Instrument Proficiency Check).

In the interim, I'm reviewing all the approach plates for Erie, PA and Lynchburg, VA where my daughter lives with her husband and children.

Forget about the weather honey!  We're comin' down!!