K versus J Maintenance Costs

[Seanhoya]

On 4/11/2021 at 4:21 PM, A64Pilot said:

If you have a real need or use for a turbo, by all means get a turbo.

‘I live in Fl and may never go over any real mountains, and if I do the J model is perfectly happy at 15,000 or 16,000, maybe higher. It just takes time to get there, and once there it’s sort of a dog compared to a turbo,but if your only going there once or twice a year or less do you need a turbo?

Which is completely different of course for those that live at altitudes that I normally fly at, and have mountains nearby 

‘A lot of how much more does it cost has to do with your familiarity of a turbo and your desire to use it, but that I mean if you always fly at max boost, it’s going to cost you more, really similar to a NA motor, run a NA motor at 65% power or less all of the time except for climb and at TBO it’s likely all the expensive parts won’t need replacing.

I’d say plan on 20% more on motor costs, it may be less and if it is, then it’s a pleasant surprise.

‘If you don’t mind me asking, what are you spending $1,000 a month on? Flying a whole lot or upgrades? I would think a turbo Mooney could be flown quite a lot and maintained perpetually on $1,000 a month, but then I’m just maintaining old avionics and not replacing with glass either.

‘So I guess I’m saying maintaining, not improving 

The $10,000 to $15,000 estimate includes everything I did annually, so it definitely includes small upgrades or reconfigurations. Frankly, I know a lot of people claim to have $2,000 annuals, but I never saw it except when working with a local A&P - certainly not with Mooney services centers.

[Seanhoya]

On 4/15/2021 at 7:45 PM, WilliamR said:

Attached is the model I built to capture all costs except upgrades for my 252.  15 years (1600 hours) of information summarized on the Ops Cost Summary sheet.  Note, I do my own oil changes and minor work as allowed by the CFRs.  Cost of parts but not labor are included in those cases.  I also do not include costs associated with detailing/washing the plane.  I do not abuse the engine and stay out of the red box but have had to replace cylinders (happy to show anyone 15 years of JPI downloads). 

I do keep the plane maintained to high standards as I work to maintain 100% dispatch reliability.  So, I'm sure my costs are somewhat on the high side.

Hope this helps.

William

AircraftStatusSheet 12-27-20.xlsx 167.72 kB · 43 downloads

William - those are impressive maintenance records! Do you have any rules of thumb for staying out of the "red box" in a turbo-charged engine? Do you not lean as aggressively? And what about LOP in a turbo-charged engine? Thanks - Sean. 

[carusoam]

Sean,

There are a few well written posts around here for M20K ops... including LOP.

Find the writings of..... @jlunseth also posted above...

Best regards,

-a-

[gsxrpilot]

5 hours ago, Seanhoya said:

William - those are impressive maintenance records! Do you have any rules of thumb for staying out of the "red box" in a turbo-charged engine? Do you not lean as aggressively? And what about LOP in a turbo-charged engine? Thanks - Sean. 

My 252 spends more time LOP than not. My rule of thumb is simple, never run LOP over 65% power. That way the "red box" doesn't exist, your engine is working easy, temps are cool, and it all take you to TBO without the need to replace cylinders or turbo on the way. Your engine will thank you. Want to go faster? Go higher.

(65% x 210hp)/13.7 = 9.96 or 10 gph - TSIO360MB. Fly at 10gph or less LOP in the 252 for 65% or less HP.

(65% x 220hp)/13.7 = 10.43 or 10.5 gph - TSIO360SB. Fly at 10.5 gph or less LOP in the Encore for 65% or less HP.

I flew my 252 at 9.5 gph for 5 years and the final 700 or so hours to TBO. 

 

[A64Pilot]

6 hours ago, Seanhoya said:

The $10,000 to $15,000 estimate includes everything I did annually, so it definitely includes small upgrades or reconfigurations. Frankly, I know a lot of people claim to have $2,000 annuals, but I never saw it except when working with a local A&P - certainly not with Mooney services centers.

Understood, I’ve always done my own annuals and until recently I worked at an aircraft manufacturing plant, so all kinds of common hardware was free.

‘That’s come to an end and I’m still struggling with what do people do, buying a couple dollars of screws etc from Aircraft Spruce and paying $10 to ship an ounce is getting old fast.

[A64Pilot]

22 minutes ago, gsxrpilot said:

My 252 spends more time LOP than not. My rule of thumb is simple, never run LOP over 65% power. 

 

 

I do the same for my NA motor. for me it’s 22 squared and that’s less than 65%, above a altitude where 22” isn’t possible for every inch of manifold pressure decrease, add 1000 RPM, it’s not exact of course but close enough for me.

‘I’ll even use the mixture as a sort of throttle, if I’m just cruising around or traveling with slower aircraft instead of reducing manifold pressure, I’ll lean it out more, she will run smoothly at 6 GPH at 22 squared but not much less than that.

‘Once well LOP fuel burn determines power output 

[aviatoreb]

40 minutes ago, gsxrpilot said:

My 252 spends more time LOP than not. My rule of thumb is simple, never run LOP over 65% power. That way the "red box" doesn't exist, your engine is working easy, temps are cool, and it all take you to TBO without the need to replace cylinders or turbo on the way. Your engine will thank you. Want to go faster? Go higher.

(65% x 210hp)/13.7 = 9.96 or 10 gph - TSIO360MB. Fly at 10gph or less LOP in the 252 for 65% or less HP.

(65% x 220hp)/13.7 = 10.43 or 10.5 gph - TSIO360SB. Fly at 10.5 gph or less LOP in the Encore for 65% or less HP.

I flew my 252 at 9.5 gph for 5 years and the final 700 or so hours to TBO. 

 

Its picking on the details and I am not sure if the precision deserves it but...

Is there any difference in the physical setup oof the 210 252 engine and the 220 encore engine?  Most particularly are the cylinders different?  Since at the end of the day its ICP - pressure that is a major target of the red box concept.  So 65% of 220 =10.5 is higher pressure if it is in the same cylinders. Still pretty low so it probably doesn't matter a lot.

My engine the tsio520nb is setup at 305 hp for the max.  So I use that.  But one could use - 310 since that is max in most applications of the tsio520nb.  But many are set at 325 max and a few set at 335 max.

[Hank]

7 hours ago, A64Pilot said:

Understood, I’ve always done my own annuals and until recently I worked at an aircraft manufacturing plant, so all kinds of common hardware was free.

‘That’s come to an end and I’m still struggling with what do people do, buying a couple dollars of screws etc from Aircraft Spruce and paying $10 to ship an ounce is getting old fast.

I buy bags of 100 screws. It's also a quick Saturday lunch run, ~45 minutes, to KFFC where Spruce is located. I don't know and will not find out what shipping is on a case of oil; I generally get two cases, several bags of screws and whatever else I need. 

[Ibra]

On 4/10/2021 at 6:46 PM, Seanhoya said:

Does anyone have estimates for Js or Ks which might be data points for comparison?

I think I did few calculations once, if you fly 1990 K at 18kft & 1980 J at 8kft you will break-even at 20kNM/year, bellow that you better getting the J, above that you get the K, nothing beats K efficiency when flying LOP at higher levels !

If one fly the K under 8kft and less than 20kNM/year, they are throwing extra 3-5AMU per year away on fixed costs and they have locked 30-50AMU from the purchase price away

Also from efficiency, no point flying J above 8kft unless you have load of tailwind above that, one can fly J up to FL200 when it’s light on good day and enough commitment but what is the point? unless it’s weather, terrain or tailwind it’s only burning load of fuel to get there for nothing...

Edited April 17, 2021 by Ibra

[PT20J]

My annuals are always inexpensive because I do owner assist with a local IA who charges a flat $750 for the inspection plus an hourly rate for any work he does. But, I fix squawks as they arise so there are generally no known issues going into the inspection and anything found during the inspection that isn't an airworthiness issue (which pretty much never happens) gets fixed later after the inspection is signed off. That's almost always small stuff that I can do with a bit of supervision. This year there was some extra expense because we sent both Slick mags (with about 250 hours on them since new) out for IRAN: the left because of the impulse coupling SB, and the right because it was dropping 180 RPM during run up.

Skip

[kortopates]

Bottom line is that maintenance cost really aren't an important consideration in deciding between a NA aircraft and turbo aircraft. The important question is if you'll be using the plane for more than short hamburger runs and able to take advantage of the turbo in flying it in the upper teens and don't mind using O2. If so, the turbo advantages in flying above the weather and just finding a smooth ride above the summer turbulence are huge; not to mention the much faster sppeds in the upper teens approaching 200kts. Once you've experienced these benefits, very few us ever go back to a NA aircraft. Having 100% power to the flight levels is just too much to give up once you're used to it.   

Edited April 19, 2021 by kortopates

[A64Pilot]

On 4/17/2021 at 6:21 PM, Hank said:

I buy bags of 100 screws. It's also a quick Saturday lunch run, ~45 minutes, to KFFC where Spruce is located. I don't know and will not find out what shipping is on a case of oil; I generally get two cases, several bags of screws and whatever else I need. 

I was based out of KABY so I would fly up to KFFC myself.

‘I guess what I need to do ideally is develop a list of common hardware required and just make a one time $500 buy

[Will.iam]

14 minutes ago, A64Pilot said:

I was based out of KABY so I would fly up to KFFC myself.

‘I guess what I need to do ideally is develop a list of common hardware required and just make a one time $500 buy

I think a purchase over $250 gets free shipping. Last time i was on the phone with them ordering the saleman pointed that out so i bought another oil filter to get me over the limit. 

[A64Pilot]

16 hours ago, Will.iam said:

I think a purchase over $250 gets free shipping. Last time i was on the phone with them ordering the saleman pointed that out so i bought another oil filter to get me over the limit. 

One wonders if that would work for a case or two of oil.

I like Spruce, Lord knows they serve a need, but $12 shipping for a position light bulb is tough to swallow, I guess I need to try the $250 thing, just build up the wish list first

[will1874]

On 4/15/2021 at 1:45 PM, WilliamR said:

Attached is the model I built to capture all costs except upgrades for my 252.  15 years (1600 hours) of information summarized on the Ops Cost Summary sheet.  Note, I do my own oil changes and minor work as allowed by the CFRs.  Cost of parts but not labor are included in those cases.  I also do not include costs associated with detailing/washing the plane.  I do not abuse the engine and stay out of the red box but have had to replace cylinders (happy to show anyone 15 years of JPI downloads). 

I do keep the plane maintained to high standards as I work to maintain 100% dispatch reliability.  So, I'm sure my costs are somewhat on the high side.

Hope this helps.

William

AircraftStatusSheet 12-27-20.xlsx 167.72 kB · 65 downloads

William, 

Thanks for posting your numbers.  I've been looking for something like that.  I have a question regarding the line item in the "Ops Cost Summary" tab that's labeled "Other Misc. Maint". The value you have there is $66.90.  That number multiplied by your total operating hours of 1595.6 (Hobbs end - Hobbs start) yields a whopping $106,745 spent on miscellaneous maintenance over the last 3 years.  I must be missing something there.  Where are you getting the $66.90/hour operating cost for miscellaneous maintenance?

[WilliamR]

The 66.90 per hour is a formula based on total maintenance over the last 15 years not already accrued for (mags, engine overhaul, etc are accruals) divided by hours flown.  Yes, if you multiply 66.90 by 1595 hours, you get $106M over the last 15 years.  I only showed three years of maintenance, but there's much more in this model.  I wish I had the time to fly 1600 hours in three years.  These misc maintenance items include things like replacing a failing KI-256 (although that stupid thing seems to die so regularly, you'd think I'd keep an accrual for it), or replacing tires or brakes.  If you right click over the sheets at the bottom, you can unhide all of the sheets that feed that number.  Also, if you left click on cell E47 on the Ops Cost Summary sheet, you will see the entire formula and al the sheets and cells it pulls from.

Hope that helps.   Happy to go into any detail in the model.  I analyze financials by trade, so I geek out on stuff like this.

 

William

[aviatoreb]

21 minutes ago, WilliamR said:

The 66.90 per hour is a formula based on total maintenance over the last 15 years not already accrued for (mags, engine overhaul, etc are accruals) divided by hours flown.  Yes, if you multiply 66.90 by 1595 hours, you get $106M over the last 15 years.  I only showed three years of maintenance, but there's much more in this model.  I wish I had the time to fly 1600 hours in three years.  These misc maintenance items include things like replacing a failing KI-256 (although that stupid thing seems to die so regularly, you'd think I'd keep an accrual for it), or replacing tires or brakes.  If you right click over the sheets at the bottom, you can unhide all of the sheets that feed that number.  Also, if you left click on cell E47 on the Ops Cost Summary sheet, you will see the entire formula and al the sheets and cells it pulls from.

Hope that helps.   Happy to go into any detail in the model.  I analyze financials by trade, so I geek out on stuff like this.

 

William

If you want my recently overhauled KI256 - overhauled by the best - Brambles and it only has 200 or 250 hrs on it - removed for panel upgrade last month.  Make me an offer - I bet I take it.

[WilliamR]

Oh, thank you.  That is very thoughtful, but I just replaced mine last summer.  Hoping it lasts me just a few more years of ownership before stepping up.

 

William

[will1874]

The 66.90 per hour is a formula based on total maintenance over the last 15 years not already accrued for (mags, engine overhaul, etc are accruals) divided by hours flown.  Yes, if you multiply 66.90 by 1595 hours, you get $106M over the last 15 years.  I only showed three years of maintenance, but there's much more in this model.  I wish I had the time to fly 1600 hours in three years.  These misc maintenance items include things like replacing a failing KI-256 (although that stupid thing seems to die so regularly, you'd think I'd keep an accrual for it), or replacing tires or brakes.  If you right click over the sheets at the bottom, you can unhide all of the sheets that feed that number.  Also, if you left click on cell E47 on the Ops Cost Summary sheet, you will see the entire formula and al the sheets and cells it pulls from.
Hope that helps.   Happy to go into any detail in the model.  I analyze financials by trade, so I geek out on stuff like this.
 
William

Thanks for the clarification. When I saw the miscellaneous maintenance number I kinda blacked-out and didn't think about how much flying that would be.

But...it's a much larger number than I was expecting. Regarding your maintenance expenditures, it looks like 2007 was a particularly rough year. Sorry to pry, but what's that $11,238 for? It's isn't labeled. And it seems there have been years where your annual inspection has cost much more than you've planned for. Would you say that is common through the fleet? Or particular to the K? Or does it just depend on the airplane?

I'm not an owner yet (never have been). But I'd been planning on $3k - $4k for an annual. I understand the first one would likely go well above that.

Thanks,

Will


Sent from my iPhone using Tapatalk

[WilliamR]

Yeah, $100K is a lot of money.  For perspective, misc. maint. is still cheaper than fuel per hour (assuming rich of peak).  Hangar rent by hours flown is close behind misc. maint.

 

Column C for 2007. 

4/6/2007		Repair structural tube	$  8,662.00
6/18/2007		Trouble shoot intercomm issue	$  129.00
7/5/2007		New mic key and wiring, trouble shoot intercomm issue	$  920.20
10/5/2007		Replace avionics master, trouble shoot intercomm issue	$  678.72
10/30/2007		New Intercomm	$  464.28
10/30/2007		Intercomm replacement labor	$  384.28

Anyway, the tube repair was due to damage found just under the NACA vent just in front of the cabin door.  When I had the PPI done, we pulled a few interior panels and the tubes looked really good.  That and given the plane was always hangered I chose not to have the full tube inspection done per the service bulletin.  The next year, the service center that was doing the annual pulled the panels and found the damage due to rust that was just beyond tolerance.  I spun the wheel of chance and lost.  They pulled the skin in that area and had someone weld a very long sleeve over the damaged area.  They initially said the whole frame was now destroyed because of that one tube.  Thankfully, I guess, they decided to play ball.  

The intercom issue was intermittent and the trouble shooting costs got a little higher than I wanted.  Also, one shop I worked with on that was less than scrupulous.  I argued, gave up and vowed never to use them again despite being right next to my hangar.  Still didn't fix the problem.  So happy they no longer exist. I hate shops that chuck parts at a problem.

The large cost in 2012 was like death by a thousand cuts.  New cylinder, two intake tubes, and other things.  A plane with old systems can slowly bleed you.  A trim servo for the KFC-150 autopilot here, an alternator there and things start to cost. 

More info than you probably wanted, but there's the story.  Oh, every few years I've changed up inspectors for one reason or another.  The first year they always seem to find something the previous inspector hadn't seen (look at 2012 then look at 2013).

Last word here... I'm not hard on my equipment whether it be the plane or my Porsches.  Old crap just breaks.  My plane is 30+ years old with some things that old. I do maintain my plane to a high level; probably to the same level as most people on here but maybe better than the general Mooney population.

William

 

[Ragsf15e]

2 hours ago, will1874 said:

Thanks for the clarification. When I saw the miscellaneous maintenance number I kinda blacked-out and didn't think about how much flying that would be.

But...it's a much larger number than I was expecting. Regarding your maintenance expenditures, it looks like 2007 was a particularly rough year. Sorry to pry, but what's that $11,238 for? It's isn't labeled. And it seems there have been years where your annual inspection has cost much more than you've planned for. Would you say that is common through the fleet? Or particular to the K? Or does it just depend on the airplane?

I'm not an owner yet (never have been). But I'd been planning on $3k - $4k for an annual. I understand the first one would likely go well above that.

Thanks,

Will


Sent from my iPhone using Tapatalk

You will find out that your operation costs quickly grow beyond your purchase price.  Quickly.  I budget ~$18k /year for everything to cover ~80 hours (fuel, insurance, hangar, maint, etc).  Usually this works out, but not always.  If you need expensive engine work or buy new avionics, you’ll blow right past that.  I’ve had $3,500 annuals and $13000 annuals.  The inspection is typically $1500.  The price I pay is usually ~$4-6k because it includes all the stuff that gets worked on.  Fuel, hangar, and insurance (mostly) are known and relatively stable costs. Maintenance, engine work, and avionics are a great unknown.

His $120k over 15 years seems about right.

[A64Pilot]

16 hours ago, WilliamR said:

 

Anyway, the tube repair was due to damage found just under the NACA vent just in front of the cabin door.  When I had the PPI done, we pulled a few interior panels and the tubes looked really good. 

That’s exactly where I am now as a new owner. I have a rusted tube under the panel, but all others look fine, At this point it’s just surface rust, but to me it’s made no sense, what was the cause of this rust in what should be a dry area? why is it only one tube? I was thinking maybe it had masking tape on it at one time, I’ve seen a tube rusted from that before.

The NACA duct and vent, that must be it, until I read your post I didn’t think about it, but if there is any rain or even IMC, your pumping in water and or moisture right in that area.

‘Now I know the cause and will keep that vent closed unless it’s VFR and no rain

Quote

 

 

Edited April 21, 2021 by A64Pilot

[WilliamR]

Well, what really helped the rust propagate below the vent was the old fibrous insulation.  Of course, I changed to closed cell for the whole plane after the repair was made.

[dfurst]

I have had a '62 C, '80 K and now on to a '94 R.  I second what @kortopates said.  If you need the turbo and plan to fly above 12K most of the time get the K.  What is most?  More then 30%?  40%?  up to you.

I live on the east coast and fly IFR.  Besides an early flight to 14K just because I could, I only had one flight in 10 years over 11K for weather.  Family didn't like wearing masks.  Oxygen tanks mysteriously ran empty 3 or 4 years in to ownership and I never bothered filling them again.  My choice.

The previous owner overhauled the turbo charger at 800 hours. It lasted me past TBO when I sold the plane. Overall maintenance was a little higher with 6 cylinders but nothing from the turbo except normal maintenance  in 10 years.

I took very good care of the Turbo. Kept it cool, did a cool down after every flight.  The biggest challenge was keeping it under 40" on take off.  The early K's would let you over boost.  I learned to hold brakes on take off until 38", let go of the brakes and it would get to 40" by halfway down runway.  Keep in mind home airport is a short runway so I need max performance every take off.  Bigger runways I would take off at 36" and back off pretty quick.  Ran it LOP most of the time, keeping cylinders and turbo cool.  Some hot days I couldn't get the temp low enough to make me comfortable so I would go ROP and burn extra fuel to get turbo and cylinders in right temp range.

IMHO if you are going to fly >12K a significant amount of time, the K is great.  For me I specifically didn't want the Turbo in my new plane and I am very happy without it.  Now, if I move West I may change my mind.  I also now have an extra 90hp so that helps < 10K.

One thing to keep in mind is landing, the K is nose heavy.  Learn how not to drop the nose when landing.