Time limited parts

[FlyDave]

All,

 

I'm posting this poll to get a feel for how people are dealing with parts that have a recommended life span in years or engine/flight hours.

On my J I had the mags rebuilt at the 500 hour mark per, I believe, manufacturer recommendation. I went from having no problems with my mags to issues that took 2 months and $1,500 to resolve.

Prior to having them rebuilt, a friend and very experienced A&P/IA said to replace/rebuild them when they fail. He proceeded to tell me a story of a guy that bought a plane with an alternator that had 1,100 hours on it. The owner was going to fly the plane to Hawaii and said install a new alternator. My friend said he didn't think it was a good idea as the alternator seemed to be performing fine but did as the owner requested. The new alternator failed ~300 miles from Hawaii.

I know there isn't one right answer, I'm just looking for this communities practices.

Also, please write any additional comments not addressed in this poll.

 

Thanks,

 

Dave

 

 

[bonal]

For me I think if it ain't broke don't fix it. So on condition is my choice. I have read so many stories where a recently serviced part ends up failing. This approach requires that one is very diligent about inspection and upkeep.

[N33GG]

For me, as well, I pretty much fall in the "if it ain't broke don't fix it" crowd as well.  However, if I even get a hint something is wrong with my aircraft, I aggressively go after repair and/or replace with new.  Most of us Mooney pilots are flying older machines, and trying to pinch pennies when something is wrong is not on my list. 

 

Bottom line is you pay your money and take your chances, either way.

 

FWIW...YMMV etc.

[pinerunner]

I'm pretty much in the fix when it needs it. I also mostly trust my mechanic who's also an inspector. I combine that with avidly reading the Busch/Deakins articles and watching the vids. Then I discuss with my mechanic. I actually like working on the owner servicable parts and tracking leaks and puddles to their source. Oil testing, engine monitor. We've got quite an arsenal of tools to either give us some peace of mind or make us crazy. Take your pick.

[Sabremech]

I agree with everyone so far, on condition for me. I'm the mechanic and inspector on my airplane!

 David

[KSMooniac]

I'm On Condition for everything except my siamese mag.  It gets INSPECTED every 500 hours by an expert, and whatever is deficient is fixed.  It is not an automatic overhaul or rebuild.  If I had the separate mags, I would stagger them such that each gets inspected every 500 hours, but not both at the same time.

[Andy95W]

I agree with everyone so far, on condition for me. I'm the mechanic and inspector on my airplane!

 David

Same here.

If I start getting squeamish about something, like magnetos, I may do something about it- but never 2 mags at the same time.

[Wildhorsesracing]

The flight school where I took my training had an engine reach TBO (2400) but it was running fine.  They followed conventional wisdom and had it replaced.  That plane had nothing but problems for months afterwards, everything from lack of power to sparkplug fouling.  All of the items were directly related to the break in of a new engine.   Sad fact is if they left it alone it probably would've gone on for many, many more hours before needing major service. 

[jetdriven]

I run everything on condition EXCEPT magnetos. Especially the Bendix dual magneto. IRAN every 500hr. Treat that thing with great care, and use a qualified shop that knows these mags extremely well and use great care installing it.  Such as the new star washers and the undated clamps. No exceptions on this.

 

Running equipment on condition means monitor the condition, not fly till failure. Also, mitigate the hazard and install equipment to eliminate consequences of things failing.

 

Vacuum pump: use the CV1J4 filter and install a standby vacuum system and an electric backup attitude gyro if you fly IFR.   Some vacuum pumps have a wear port you can inspect the vane length and replace when indicated.  My old engine ran 900hr on the same vacuum pump and it was still going strong. However, I would have run it until it failed as the CV1J4 filter eliminates the gyro failures caused by a bad pump. I've got two attitude gyros. And two vacuum sources. The consequence if either failing is greatly reduced.

 

Alternator. VFR only is not much consequence. For an IFR airplane, install the Concorde AXC battery and do the yearly capacity test to ensure you have 30 minutes reserve capacity. Also know your aircraft and load shed everything down to 1 nav/com/gps and the transponder. You can fly a lot longer than 30 minutes in this condition. Keep the voltmeter in your scan. Three people I know in the last couple years first indication of alternator failure was a failure to transmit and radio displays going out, and right then, complete electrical system failure.  All 3 had engine monitors that show voltage right there. You are flying an electric airplane. The alternator drops offline and the voltage immediately drops to 12.2 from 14.1. Notice that, then load shed.   Lycoming engines, inspect the belt tension, and check the ring terminal to the field wire on the alternator case. It breaks every 100-200 hours. Visually inspect the wire strands going into the crimp terminal, often there are only 1 or 2 single strands holding it on.  Unscrew the terminal and look in there. Give it the pull test.

 

Electric fuel pump is a backup to the mechanical pump. replace when it no longer operates normally.  Our mechanical fuel pump went bad and the symptom was lower and wandering fuel pressure at higher altitude. We monitored, diagnosed, then replaced.

 

Spark plugs, if it wont go smooth to 50 LOP, investigate. Ohm test, regap. It may be something else, but its something. Lots of people I know had 300-500 hour Champion plugs, new plugs cured the rough running at lean cruise settings.

[Piloto]

One criteria I use is prior ADs and SBs. If there was an issue with a 10 year old component ADs and SBs would have been issued by now. New components like the Acclaim TN tail AD or cylinder premature failure is an example of surprises you can get on new components. "Old stuff is proven, new stuff is to be".

 

José 

[Ned Gravel]

As I was approaching 2000 hours on my engine, Clarence and I thought it would be OK to run it on condition beyond 2000 hours.  

 

Then the engine spoke up.  Oil leak at the through bolt behind #2.  When we checked, it was actually a 6" crack in the crankcase. Time was up and it was only at 1970 hours.  

 

Know when your engine speaks to you.

[garytex]

Jetdriven's got it right about mags.   I have multiple experiences that have convinced me that more than 500 hrs on mags without a good IRAN is bad medicine. Everything else on condition, as I am VFR

[schule]

Also high altitude use can cause issues for mags. Otherwise Part 91 on condition unless regs or ADs drive otherwise.