Engine Dependability

[O. Sami Saydjari]

I talked to TCM today to register that I am the new owner of one of
their engines. Just in passing, I mentioned that their engine failed
recently within a few hundred hours after major overhaul. They seemed
completely uninterested in knowing this fact. I asked if they kept
actual statistics on actual dependability of their engines. She said
that they did not, to the best of her knowledge. That seems quite odd.

Where do they get TBO numbers from. I always assumed there was some
serious historical statistical date to back these up. Does anyone keep
these statistics? Perhaps A&Ps report such failures? Overhaul shops
maybe? I sure hope someone is tracking the information.

-Sami
N2057M, Piper Turbo Arrow III

[Newps]

"O. Sami Saydjari" > wrote in message
...
> I talked to TCM today to register that I am the new owner of one of
> their engines. Just in passing, I mentioned that their engine failed
> recently within a few hundred hours after major overhaul. They seemed
> completely uninterested in knowing this fact. I asked if they kept
> actual statistics on actual dependability of their engines. She said
> that they did not, to the best of her knowledge. That seems quite odd.

Ah, a new owner. Continental makes bulletproof bottom ends. Case, crank
and cam are terrific, they will never give you any problems. Avoid new
Continental cylinders like the plague. Total junk. I think ECI has the
better cylinders, some like Milleniums.


>
> Where do they get TBO numbers from. I always assumed there was some
> serious historical statistical date to back these up. Does anyone keep
> these statistics? Perhaps A&Ps report such failures? Overhaul shops
> maybe? I sure hope someone is tracking the information.

Nobody is tracking the info.

[Dan Luke]

"O. Sami Saydjari" wrote:
> Just in passing, I mentioned that their engine failed
> recently within a few hundred hours after major overhaul.
> They seemed completely uninterested in knowing
> this fact.

No surprise. In the seven+ years I've been involved in general
aviation, I don't think I've ever heard anyone say anything nice about
TCM.
--
Dan
C172RG at BFM

[Greg Copeland]

On Mon, 19 Apr 2004 13:02:11 -0600, Newps wrote:

>
> "O. Sami Saydjari" > wrote in message
> ...
>> I talked to TCM today to register that I am the new owner of one of
>> their engines. Just in passing, I mentioned that their engine failed
>> recently within a few hundred hours after major overhaul. They seemed
>> completely uninterested in knowing this fact. I asked if they kept
>> actual statistics on actual dependability of their engines. She said
>> that they did not, to the best of her knowledge. That seems quite odd.
>
> Ah, a new owner. Continental makes bulletproof bottom ends. Case, crank
> and cam are terrific, they will never give you any problems. Avoid new
> Continental cylinders like the plague. Total junk. I think ECI has the
> better cylinders, some like Milleniums.
>
>
>>
>> Where do they get TBO numbers from. I always assumed there was some
>> serious historical statistical date to back these up. Does anyone keep
>> these statistics? Perhaps A&Ps report such failures? Overhaul shops
>> maybe? I sure hope someone is tracking the information.
>
> Nobody is tracking the info.

Well, I guess that puts us back to the original question. I, like the
orginal article's author, thought historical statistics were used to
establish TBO numbers. If no one is tracking this information, where do
the TBO numbers come from? Insurance liability statistics from wrecks?

[Newps]

"Greg Copeland" > wrote in message
...


> Well, I guess that puts us back to the original question. I, like the
> orginal article's author, thought historical statistics were used to
> establish TBO numbers. If no one is tracking this information, where do
> the TBO numbers come from? Insurance liability statistics from wrecks?

TBO comes from two places.

1) Marketing

2) A Guess

[Greg Copeland]

On Mon, 19 Apr 2004 13:53:36 -0600, Newps wrote:

>
> "Greg Copeland" > wrote in message
> ...
>
>
>> Well, I guess that puts us back to the original question. I, like the
>> orginal article's author, thought historical statistics were used to
>> establish TBO numbers. If no one is tracking this information, where do
>> the TBO numbers come from? Insurance liability statistics from wrecks?
>
> TBO comes from two places.
>
> 1) Marketing
>
> 2) A Guess

LOL! Is anyone else bothered by this? I guess it's not really saying
MTBF, it's just saying, your engine is ganna be tired when it hit this
number. So, I guess that really isn't all that bad after all.

[O. Sami Saydjari]

Greg Copeland wrote:

> On Mon, 19 Apr 2004 13:53:36 -0600, Newps wrote:
>
>
>>"Greg Copeland" > wrote in message
...
>>
>>
>>
>>>Well, I guess that puts us back to the original question. I, like the
>>>orginal article's author, thought historical statistics were used to
>>>establish TBO numbers. If no one is tracking this information, where do
>>>the TBO numbers come from? Insurance liability statistics from wrecks?
>>
>>TBO comes from two places.
>>
>>1) Marketing
>>
>>2) A Guess
>
>
> LOL! Is anyone else bothered by this? I guess it's not really saying
> MTBF, it's just saying, your engine is ganna be tired when it hit this
> number. So, I guess that really isn't all that bad after all.

I, for one, prefer to base my decisions on facts instead of
speculations. How do they know the engine will be tired after x hours?
What does tired mean? The only thing that would be meaningful to
owners is probability of failure at X hours.

It does not seem that collecting the data and calculating MTBF would be
that hard.

I sure hope the engineers who designed the engine did not use the same
attitude with respect to the components they used! "Crankshaft A is 20%
cheaper than Crankshaft B? Well, who cares, everyone knows that
everyone just makes the reliability numbers up anyway. Let's use
Crankshaft A." Arg!

>
>

[EDR]

There is too much variability in operation to accurately track
reliability/dependability of an engine.
TBO comes from the manufacturer's test stand and flight test data under
controlled conditions. Same place the 55/65/75% power data comes from.

[O. Sami Saydjari]

OK. I have gone back through my logs and compiled the following
information on my aircraft.

Since my airplane was born around 10/13/1977, it has had 4 engine
overhauls (including the most recently one that I am having done now).
The Mean Time Between Failure has been 877 hours of operation, 7
calendar years. The most recent failure took place within 318 hours of
the last overhaul. The table below gives the details:

Overhaul 1....10/01/79...826 hrs...2 yrs
Overhaul 2....05/26/85..1901 hrs...5.6 yrs
Overhaul 3....11/18/89..1288 hrs...4.5 yrs
Overhaul 4....04/06/04.. 318 hrs..14.4 yrs.
-------------------------------------------
Average................. 877 hrs...7 yrs

This is a far cry from the 1400 TBO on the first engine
(overhaul 1) and the 1800 TBO on the second (overhauls 2,3 and 4).

If anyone else is willing to post their data, it might make for some
interesting information in a thread.

-Sami

O. Sami Saydjari wrote:

> I talked to TCM today to register that I am the new owner of one of
> their engines. Just in passing, I mentioned that their engine failed
> recently within a few hundred hours after major overhaul. They seemed
> completely uninterested in knowing this fact. I asked if they kept
> actual statistics on actual dependability of their engines. She said
> that they did not, to the best of her knowledge. That seems quite odd.
>
> Where do they get TBO numbers from. I always assumed there was some
> serious historical statistical date to back these up. Does anyone keep
> these statistics? Perhaps A&Ps report such failures? Overhaul shops
> maybe? I sure hope someone is tracking the information.
>
> -Sami
> N2057M, Piper Turbo Arrow III
>

[O. Sami Saydjari]

EDR,

I am afraid that I beg to differ. You certainly may question the value
of an "average" TBO to decision-making, but you can track the numbers
quite accurately (assuming correct reporting). It would really only
take the cooperation of a small number of overhaul shops, some A&P
mechanics and such.

In the same way, one could question the value of the accident rate of
the "average" GA pilot. Granted that all of us are above average :)
(apologies to Garrison Keillor), but such statistics can be useful
starting points, for example, to see if trends are improving or if a
given measure is worthwhile. Similarly, average disease mortality rates
are useful for medical treatment, despite no person being average.

I do not mean to beat a dead horse, but I really think it would be a
good idea, from an engineering perspective, to collect and report this data.

-Sami
N2057M, Piper Turbo Arrow III

EDR wrote:

> There is too much variability in operation to accurately track
> reliability/dependability of an engine.
> TBO comes from the manufacturer's test stand and flight test data under
> controlled conditions. Same place the 55/65/75% power data comes from.

[O. Sami Saydjari]

Oops...typo in row 2, column 3. It should be 1075 and not 1901. Sorry.

-Sami

O. Sami Saydjari wrote:

> OK. I have gone back through my logs and compiled the following
> information on my aircraft.
>
> Since my airplane was born around 10/13/1977, it has had 4 engine
> overhauls (including the most recently one that I am having done now).
> The Mean Time Between Failure has been 877 hours of operation, 7
> calendar years. The most recent failure took place within 318 hours of
> the last overhaul. The table below gives the details:
>
> Overhaul 1....10/01/79...826 hrs...2 yrs
> Overhaul 2....05/26/85..1901 hrs...5.6 yrs
> Overhaul 3....11/18/89..1288 hrs...4.5 yrs
> Overhaul 4....04/06/04.. 318 hrs..14.4 yrs.
> -------------------------------------------
> Average................. 877 hrs...7 yrs
>
> This is a far cry from the 1400 TBO on the first engine
> (overhaul 1) and the 1800 TBO on the second (overhauls 2,3 and 4).
>
> If anyone else is willing to post their data, it might make for some
> interesting information in a thread.
>
> -Sami
>
> O. Sami Saydjari wrote:
>
>> I talked to TCM today to register that I am the new owner of one of
>> their engines. Just in passing, I mentioned that their engine failed
>> recently within a few hundred hours after major overhaul. They seemed
>> completely uninterested in knowing this fact. I asked if they kept
>> actual statistics on actual dependability of their engines. She said
>> that they did not, to the best of her knowledge. That seems quite odd.
>>
>> Where do they get TBO numbers from. I always assumed there was some
>> serious historical statistical date to back these up. Does anyone keep
>> these statistics? Perhaps A&Ps report such failures? Overhaul shops
>> maybe? I sure hope someone is tracking the information.
>>
>> -Sami
>> N2057M, Piper Turbo Arrow III
>>
>

[[email protected]]

On 19-Apr-2004, "O. Sami Saydjari" > wrote:

> Where do they get TBO numbers from. I always assumed there was some
> serious historical statistical date to back these up. Does anyone keep
> these statistics? Perhaps A&Ps report such failures? Overhaul shops
> maybe? I sure hope someone is tracking the information.


My understanding is that TBO is a recommendation by the engine manufacturer
based upon engineering expectations and service history. The FAA maintains
a system for mechanics to report unusual maintenance and/or component
failure issues. These reports inform the process by which ADs are
formulated, and presumably the information also makes its way back to the
engine, airframe, and/or component manufacturer.

What broke on your engine after only a few hundred hours? Was it a factory
engine or a field overhaul? Was it under warranty? Did your mechanic file
a Maintenance Report or Defect Report?

--
-Elliott Drucker

[Aaron Coolidge]

O. Sami Saydjari > wrote:
: OK. I have gone back through my logs and compiled the following
: information on my aircraft.

<snip>
I think you may find that the TSIO360 engine is considered one of the
least reliable engines out there. This is what's keeping my from buying
a Mooney 231. I did some research into the "Service Difficulty" reports
that the FAA tracks, in concert with A&P mechanics, and it seems like
the engines just devour cylinders. The SDR info is available on the web.

From reading many ads for 231 airplanes I have seen most engines have
a top overhaul at 800 or so hours, and a major overhaul at 1600 or so
hours.

--
Aaron Coolidge (N9376J)

[O. Sami Saydjari]

>
> What broke on your engine after only a few hundred hours?

I will not really know until the overhaulers take it apart. I should
know more in a couple of weeks.

> Was it a factory
> engine or a field overhaul?

TCM overhauled it.

> Was it under warranty?

No.

> Did your mechanic file
> a Maintenance Report or Defect Report?

We shall see. I will report later, when I know more.

Just to be clear. I am not intending to whine about my particular
failure, but rather express some concern about the lack of actual data
being collected that supports decision-making about dependability of
engines.
>

[O. Sami Saydjari]

Aar
> I think you may find that the TSIO360 engine is considered one of the
> least reliable engines out there. This is what's keeping my from buying
> a Mooney 231. I did some research into the "Service Difficulty" reports
> that the FAA tracks, in concert with A&P mechanics, and it seems like
> the engines just devour cylinders. The SDR info is available on the web.
>

I also looked through service diffciulty reports, but I found it very
hard to really tell whether they were (a) representative of all
airplanes or exceptional to just a few and (b) comparatively any better
or worse than another airplane (or engine). It is not clear how one
uses SDRs as a metric....at least not to me.

[Ray Andraka]

my airplane is a 1965. Without going and digging out the logs, the
approximate times are

1991. First overhaul at 2000 hours (almost to the minute...it was on part
135 at the time so overhaul was required). That's 26 calendar years and 2000
hours. I didn't see any other engine work beyond replacing accessories and
normal maintenance before then.

2003. Second Overhaul at ~3125 hours. 12 calendar years, and 1125 hours.
First overhaul was a service limits overhaul with chrome cylinders. Second
overhaul was needed for spalled cam. It had been making metal for about 500
hours, and oil consumption was about 2.5 hrs/qt.

This is an O-540-E4B5. Normally aspirated, carbureted, 260 HP. TBO is 2000
hours

2003 Overhaul was a reman to new limits, new cylinders, new cam, reground
crank and case. about 60 hours so far.


"O. Sami Saydjari" wrote:--
--Ray Andraka, P.E.
President, the Andraka Consulting Group, Inc.
401/884-7930 Fax 401/884-7950
email
http://www.andraka.com

"They that give up essential liberty to obtain a little
temporary safety deserve neither liberty nor safety."
-Benjamin Franklin, 1759

[EDR]

In article >, O. Sami Saydjari
> wrote:

> EDR,
> I am afraid that I beg to differ. You certainly may question the value
> of an "average" TBO to decision-making, but you can track the numbers
> quite accurately (assuming correct reporting). It would really only
> take the cooperation of a small number of overhaul shops, some A&P
> mechanics and such.
> In the same way, one could question the value of the accident rate of
> the "average" GA pilot. Granted that all of us are above average :)
> (apologies to Garrison Keillor), but such statistics can be useful
> starting points, for example, to see if trends are improving or if a
> given measure is worthwhile. Similarly, average disease mortality rates
> are useful for medical treatment, despite no person being average.
> I do not mean to beat a dead horse, but I really think it would be a
> good idea, from an engineering perspective, to collect and report this data.

Sami,
Find some Pitts pilots who flys Intermediate or Advanced competition.
Ask them what the TBO is on a Lycoming AEIO-360/540.
Ask them how many hours they flew their Pitts doing competition
aerobatics (practice and contests).
The engines are 1200 or 1400 TBO (IIRC).
Most competition pilots overhaul between 600 and 700 hours.
When you go from wide open to closed throttle repeatedly, the engine
experiences higher than normal wear.

[EDR]

In article >, O. Sami Saydjari
> wrote:

> I do not mean to beat a dead horse, but I really think it would be a
> good idea, from an engineering perspective, to collect and report this data.

Yes, but unless you know how the engine was consistantly operated, you
have no understanding of why one engine goes 2000 hours and another
only 150 hours.

[Roy Smith]

In article >,
EDR > wrote:

> Sami,
> Find some Pitts pilots who flys Intermediate or Advanced competition.
> Ask them what the TBO is on a Lycoming AEIO-360/540.
> Ask them how many hours they flew their Pitts doing competition
> aerobatics (practice and contests).
> The engines are 1200 or 1400 TBO (IIRC).
> Most competition pilots overhaul between 600 and 700 hours.
> When you go from wide open to closed throttle repeatedly, the engine
> experiences higher than normal wear.

The worst engine TBO is on top fuel dragsters. It's something under 10
seconds.

[BTIZ]

did they do the overhaul?

if not.. then why should they care about the failure... it goes back to the
shop that did the overhaul

JMHO
BT

"O. Sami Saydjari" > wrote in message
...
> I talked to TCM today to register that I am the new owner of one of
> their engines. Just in passing, I mentioned that their engine failed
> recently within a few hundred hours after major overhaul. They seemed
> completely uninterested in knowing this fact. I asked if they kept
> actual statistics on actual dependability of their engines. She said
> that they did not, to the best of her knowledge. That seems quite odd.
>
> Where do they get TBO numbers from. I always assumed there was some
> serious historical statistical date to back these up. Does anyone keep
> these statistics? Perhaps A&Ps report such failures? Overhaul shops
> maybe? I sure hope someone is tracking the information.
>
> -Sami
> N2057M, Piper Turbo Arrow III
>

[Greg Copeland]

On Mon, 19 Apr 2004 15:37:43 -0500, O. Sami Saydjari wrote:

>
>
> Greg Copeland wrote:
>
>> On Mon, 19 Apr 2004 13:53:36 -0600, Newps wrote:
>>
>>
>>>"Greg Copeland" > wrote in message
...
>>>
>>>
>>>
>>>>Well, I guess that puts us back to the original question. I, like the
>>>>orginal article's author, thought historical statistics were used to
>>>>establish TBO numbers. If no one is tracking this information, where do
>>>>the TBO numbers come from? Insurance liability statistics from wrecks?
>>>
>>>TBO comes from two places.
>>>
>>>1) Marketing
>>>
>>>2) A Guess
>>
>>
>> LOL! Is anyone else bothered by this? I guess it's not really saying
>> MTBF, it's just saying, your engine is ganna be tired when it hit this
>> number. So, I guess that really isn't all that bad after all.
>
> I, for one, prefer to base my decisions on facts instead of
> speculations. How do they know the engine will be tired after x hours?
> What does tired mean? The only thing that would be meaningful to
> owners is probability of failure at X hours.
>
> It does not seem that collecting the data and calculating MTBF would be
> that hard.
>
> I sure hope the engineers who designed the engine did not use the same
> attitude with respect to the components they used! "Crankshaft A is 20%
> cheaper than Crankshaft B? Well, who cares, everyone knows that
> everyone just makes the reliability numbers up anyway. Let's use
> Crankshaft A." Arg!
>
>>
>>

Well, there's no doubt that having an MTBF number with each engine would
be nice to know, but I doubt you're going to get enough sampling from this
group to even begin to eliminate noise. So, until someone is able to
create a meaningful MTBF number for us, the TBO is the best we have.
Which means, exactly what it says. It says, after x-number of hours, you
should be considering an overhaul of the engine. I don't believe it
speaks to anything else. In other words, one can assume it means, should
you actually reach TBO without requiring an overhaul, at x-hours, you
should be considering it.

[Greg Copeland]

On Mon, 19 Apr 2004 23:52:14 +0000, EDR wrote:

> In article >, O. Sami Saydjari
> > wrote:
>
>> I do not mean to beat a dead horse, but I really think it would be a
>> good idea, from an engineering perspective, to collect and report this data.
>
> Yes, but unless you know how the engine was consistantly operated, you
> have no understanding of why one engine goes 2000 hours and another
> only 150 hours.

I understand what you're saying. Just the same, I believe with enough
samples, you could get a meaningful MTBF for non-utility and utility
categories. Furthermore, given enough samples for each category and using
the mean (not the average -- though ATBF may be interesting as well), as
it should provide a fair idea of the MTBF is for a given engine.

If one makes some assumptions, you can reasonably assume the MTBF is going
to be less than or equal to the TBO for a given engine. What percentage
of people run beyond TBO? Would it be fair to include these samples in a
MTBF set? After all, according to the manufacturer, you're already on
borrowed time when running beyond TBO.

[O. Sami Saydjari]

> In other words, one can assume it [TBO] means, should
> you actually reach TBO without requiring an overhaul, at x-hours, you
> should be considering it.
>

Well, OK, it sure would be nice if the industry defined TBO similarly to
the words you use above. Something like: "Warning: In the rare and
miraculous event that your engine actually reaches this number that we
pulled from some random bodily orifice, we sure will be surprised...oh,
and, unless your life insurance is up to date and you seek a big pay-off
to your beneficiaries, go do an overhaul."

OK. Just so you know, I am tongue in cheek here. I do know that some
engines make it to, and even past TBO. I just find it interesting that,
on average, mine made less than 50% of advertized TBO.

Yes, I do realize that a sampling from this newsgroup would not be
scientific, but I do think it would be interesting to share experiences.
Maybe everyone else is getting 90-110% TBOs and this is anomaly. That
would be nice to know.

-Sami

[Greg Copeland]

On Mon, 19 Apr 2004 21:40:27 -0500, O. Sami Saydjari wrote:

> Yes, I do realize that a sampling from this newsgroup would not be
> scientific, but I do think it would be interesting to share experiences.
> Maybe everyone else is getting 90-110% TBOs and this is anomaly. That
> would be nice to know.


Fair enough.

[[email protected]]

On Mon, 19 Apr 2004 21:40:27 -0500, "O. Sami Saydjari"
> wrote:

snip

>Yes, I do realize that a sampling from this newsgroup would not be
>scientific, but I do think it would be interesting to share experiences.
> Maybe everyone else is getting 90-110% TBOs and this is anomaly. That
>would be nice to know.

Have personally seen 8 or 9 "make it" to from o-haul to factory TBO.
Were installed in T-Arrow's, T-Dakota's and a couple of Senecas. Only
one that didn't make it was due to massive internal corrosion
(discovered during a mid-life crankcase repair).

Aside from day-to-day operation, frequency of use/proper storage
during periods of non-use is a big factor.

TC

[[email protected]]

O. Sami Saydjari > wrote:
> I talked to TCM today to register that I am the new owner of one of
> their engines. Just in passing, I mentioned that their engine failed
> recently within a few hundred hours after major overhaul. They seemed
> completely uninterested in knowing this fact. I asked if they kept
> actual statistics on actual dependability of their engines. She said
> that they did not, to the best of her knowledge. That seems quite odd.

> Where do they get TBO numbers from. I always assumed there was some
> serious historical statistical date to back these up. Does anyone keep
> these statistics? Perhaps A&Ps report such failures? Overhaul shops
> maybe? I sure hope someone is tracking the information.

> -Sami
> N2057M, Piper Turbo Arrow III

See http://www.avweb.com/news/columns/187037-1.html for a recent article
on TBO.

--
Jim Pennino

Remove -spam-sux to reply.

[Greg Copeland]

On Tue, 20 Apr 2004 03:38:01 +0000, jimp wrote:

> O. Sami Saydjari > wrote:
>> I talked to TCM today to register that I am the new owner of one of
>> their engines. Just in passing, I mentioned that their engine failed
>> recently within a few hundred hours after major overhaul. They seemed
>> completely uninterested in knowing this fact. I asked if they kept
>> actual statistics on actual dependability of their engines. She said
>> that they did not, to the best of her knowledge. That seems quite odd.
>
>> Where do they get TBO numbers from. I always assumed there was some
>> serious historical statistical date to back these up. Does anyone keep
>> these statistics? Perhaps A&Ps report such failures? Overhaul shops
>> maybe? I sure hope someone is tracking the information.
>
>> -Sami
>> N2057M, Piper Turbo Arrow III
>
> See http://www.avweb.com/news/columns/187037-1.html for a recent article
> on TBO.


Great link! Thanks!

[James M. Knox]

"BTIZ" > wrote in
news:kHZgc.13759$432.5418@fed1read01:

> did they do the overhaul?
>
> if not.. then why should they care about the failure... it goes back
> to the shop that did the overhaul

U assure you they have no apparent interest in the ones they do
themselves either. Our field has at least three TCM factory reman
engines in various planes, all of which broke in with the classic TCM
failure mode (zero oil usage), and all of which show the classic failure
pattern (starting to use oil at 400 hours, followed by compression
drop).

Both owners and shop have tried to get the local TCM rep to even come
out and look at the problem. Phone calls go unreturned. Letters go
unanswered. Compresses on all these engines are effectively 0/80, but
if you play with the prop long enough you can get compression readings
up in the 60's and 70's. The one time I managed to talk to the rep, his
response was "Well, hell. If you can get it to pass the annual, why do
you care?"

After four years the final response from TCM was to issue a new Advisory
Circular defining what counts as airworthy. Now readings as low as
26/80, with air hissing past both rings AND exhaust valves is perfectly
satisfactory, even for a brand new engine.

Sorry, but if Superior made jugs for my engine I would have chosen them
in a heartbeat.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

[Michael]

"O. Sami Saydjari" > wrote
> Where do they get TBO numbers from. I always assumed there was some
> serious historical statistical date to back these up. Does anyone keep
> these statistics? Perhaps A&Ps report such failures? Overhaul shops
> maybe? I sure hope someone is tracking the information.

First off, nobody is tracking this information. The engine
manufacturers don't want it tracked - the statistics would reveal how
unreliable these engines really are. TBO's are usually about 2000
hours, but I don't actually know anyone with more than 2000 hours of
piston GA experience who has not had an engine failure.

Second, the TBO numbers are not MTBF numbers. In theory, they are
based on estimated corrosion and wear of critical components. For
example, improved lubricants have had a massive effect on TBO's
without the engine manufacturers doing anything. TBO is not how long
the engine is expected to go without failing catastrophically, but how
long it's expected to go before some components are no longer within
service limits. This can cause the oil consumption to be excessive,
rated power not to be delivered, etc.

Third, catastrophic engine failure is not generally the result of the
bottom end (camshaft, crankshaft, case) though it can happen. When it
does, it generally occurs earlier rather than later, unless of course
something ugly happens (like a prop strike). Usually such failures
are in the jugs (valves are most common, though I have seen engines
literally lose a jug) or the accessories.

Fourth, the serious engineering talent at places like TCM and Lycoming
has been gone for a long time. They don't offer top pay, interesting
work, or a minimally bureaucratic work environment, so they don't
attract the top engineering talent. Their TBO's are mostly a guess,
and a marketing rather than an engineering guess at that.

Fifth, the important TBO is not hourly but calendar. I don't often
see engines go much past the calendar TBO (usually 12-15 years)
without significant top end work. I've seen lots go past hourly TBO
when flown lots - as much as 3000 hours when flown 500 hours a year.

Michael

[PaulH]

Just a tidbit - I purchased a 1969 Arrow (Lycoming IO360) a few years
ago.

There's a logbook entry at 100 hours that the engine was replaced. No
stated reason was given, nor are there any airframe entries to suggest
an accident.

TBO is not anything like MTBF. It's the manufacturer's estimate
assuming ideal operating conditions. In general, this means very
regular use with good control of temperatures. The Turbo Arrow has a
history of problems because of heat buildup.

[Dan Luke]

"Michael" wrote:
>TBO's are usually about 2000 hours, but I don't actually
> know anyone with more than 2000 hours of
> piston GA experience who has not had an engine failure.

Pardon me, Michael, but there's something puzzling about this statement,
to me. (I know only one pilot with over 2000 hours (~8,000), and he's
never had an engine failure, but that's not what puzzles me). I know
three airplanes that have gone to 2000-hr. TBO two or three times
without an engine failure. Mine went 4500 hours without one before I
bought it. Isn't that equivalent to four pilots' going 2000+ hours each
without an engine failure? How do you account for the unsettling
experiences of your acquaintences?
--
Dan
C172RG at BFM

[Michael]

"Dan Luke" > wrote
> Pardon me, Michael, but there's something puzzling about this statement,
> to me. (I know only one pilot with over 2000 hours (~8,000), and he's
> never had an engine failure, but that's not what puzzles me). I know
> three airplanes that have gone to 2000-hr. TBO two or three times
> without an engine failure. Mine went 4500 hours without one before I
> bought it. Isn't that equivalent to four pilots' going 2000+ hours each
> without an engine failure? How do you account for the unsettling
> experiences of your acquaintences?

Don't know. Were these perhaps small, 4-cylinder, carbureted,
normally aspirated low compression engines? In my experience, most
engine failures seem to occur on engines that are large, 6+ cylinder,
injected, turbocharged, high compression, or some combination. I only
know one person who had a failure with a Cont O-200, one with a Lyc
O-320, and none with a Lyc O-360. All engines are clearly not created
equal.

I think there's some self-selection going on - most pilots who stay in
GA past 1000 hours (except those who spend all their time in the right
seat of a primary trainer) tend to move into higher performance
airplanes where the engines are less reliable.

I believe something like 10% of piston engined Malibus have
experienced inflight engine failures. I would also guess that the
rate of failure in C-150's is at least an order of magnitude lower.

Michael

[Jeff]

did you find out the reason for your engine failure yet ?


"O. Sami Saydjari" wrote:

> Greg Copeland wrote:
>
> > On Mon, 19 Apr 2004 13:53:36 -0600, Newps wrote:
> >
> >
> >>"Greg Copeland" > wrote in message
> ...
> >>
> >>
> >>
> >>>Well, I guess that puts us back to the original question. I, like the
> >>>orginal article's author, thought historical statistics were used to
> >>>establish TBO numbers. If no one is tracking this information, where do
> >>>the TBO numbers come from? Insurance liability statistics from wrecks?
> >>
> >>TBO comes from two places.
> >>
> >>1) Marketing
> >>
> >>2) A Guess
> >
> >
> > LOL! Is anyone else bothered by this? I guess it's not really saying
> > MTBF, it's just saying, your engine is ganna be tired when it hit this
> > number. So, I guess that really isn't all that bad after all.
>
> I, for one, prefer to base my decisions on facts instead of
> speculations. How do they know the engine will be tired after x hours?
> What does tired mean? The only thing that would be meaningful to
> owners is probability of failure at X hours.
>
> It does not seem that collecting the data and calculating MTBF would be
> that hard.
>
> I sure hope the engineers who designed the engine did not use the same
> attitude with respect to the components they used! "Crankshaft A is 20%
> cheaper than Crankshaft B? Well, who cares, everyone knows that
> everyone just makes the reliability numbers up anyway. Let's use
> Crankshaft A." Arg!
>
> >
> >

[Jeff]

Everyone I have talked to who has this engine in their turbo arrows always
say to not fly over 65% power, if so you will not make it to TBO, the
exception is those that have an intercooler installed.
I only fly mine at 65% power, so far no problems in the year I have had it.


Aaron Coolidge wrote:

> O. Sami Saydjari > wrote:
> : OK. I have gone back through my logs and compiled the following
> : information on my aircraft.
>
> <snip>
> I think you may find that the TSIO360 engine is considered one of the
> least reliable engines out there. This is what's keeping my from buying
> a Mooney 231. I did some research into the "Service Difficulty" reports
> that the FAA tracks, in concert with A&P mechanics, and it seems like
> the engines just devour cylinders. The SDR info is available on the web.
>
> From reading many ads for 231 airplanes I have seen most engines have
> a top overhaul at 800 or so hours, and a major overhaul at 1600 or so
> hours.
>
> --
> Aaron Coolidge (N9376J)

[O. Sami Saydjari]

Not yet. Awaiting word from oerhaul shop. I will report back as soon
as I know anything.

-sami

Jeff wrote:

> did you find out the reason for your engine failure yet ?
>
>
> "O. Sami Saydjari" wrote:
>
>
>>Greg Copeland wrote:
>>
>>
>>>On Mon, 19 Apr 2004 13:53:36 -0600, Newps wrote:
>>>
>>>
>>>
>>>>"Greg Copeland" > wrote in message
...
>>>>
>>>>
>>>>
>>>>
>>>>>Well, I guess that puts us back to the original question. I, like the
>>>>>orginal article's author, thought historical statistics were used to
>>>>>establish TBO numbers. If no one is tracking this information, where do
>>>>>the TBO numbers come from? Insurance liability statistics from wrecks?
>>>>
>>>>TBO comes from two places.
>>>>
>>>>1) Marketing
>>>>
>>>>2) A Guess
>>>
>>>
>>>LOL! Is anyone else bothered by this? I guess it's not really saying
>>>MTBF, it's just saying, your engine is ganna be tired when it hit this
>>>number. So, I guess that really isn't all that bad after all.
>>
>>I, for one, prefer to base my decisions on facts instead of
>>speculations. How do they know the engine will be tired after x hours?
>> What does tired mean? The only thing that would be meaningful to
>>owners is probability of failure at X hours.
>>
>>It does not seem that collecting the data and calculating MTBF would be
>>that hard.
>>
>>I sure hope the engineers who designed the engine did not use the same
>>attitude with respect to the components they used! "Crankshaft A is 20%
>>cheaper than Crankshaft B? Well, who cares, everyone knows that
>>everyone just makes the reliability numbers up anyway. Let's use
>>Crankshaft A." Arg!
>>
>>
>>>
>

[O. Sami Saydjari]

Jeff, I have been flying mine at 65% power....and I have an
intercooler. -sami

Jeff wrote:

> Everyone I have talked to who has this engine in their turbo arrows always
> say to not fly over 65% power, if so you will not make it to TBO, the
> exception is those that have an intercooler installed.
> I only fly mine at 65% power, so far no problems in the year I have had it.
>
>
> Aaron Coolidge wrote:
>
>
>>O. Sami Saydjari > wrote:
>>: OK. I have gone back through my logs and compiled the following
>>: information on my aircraft.
>>
>><snip>
>>I think you may find that the TSIO360 engine is considered one of the
>>least reliable engines out there. This is what's keeping my from buying
>>a Mooney 231. I did some research into the "Service Difficulty" reports
>>that the FAA tracks, in concert with A&P mechanics, and it seems like
>>the engines just devour cylinders. The SDR info is available on the web.
>>
>>From reading many ads for 231 airplanes I have seen most engines have
>>a top overhaul at 800 or so hours, and a major overhaul at 1600 or so
>>hours.
>>
>>--
>>Aaron Coolidge (N9376J)
>
>

[James M. Knox]

Jeff > wrote in
:

> Everyone I have talked to who has this engine in their turbo arrows
> always say to not fly over 65% power, if so you will not make it to
> TBO, the exception is those that have an intercooler installed.
> I only fly mine at 65% power, so far no problems in the year I have
> had it.

I don't think it is so much a matter of what power as what temperature.
Reducing power helps with the temps, of course, so...

Watching the JPI EDM float around under various conditions, it's easy to
see how the cylinder temps can get out of hand, even at 65% power. The
engine is somewhat tightly cowled, no cowl flaps, and comes (originally)
with a fixed wastegate.

The Merlyn helps a lot on that, especially here in Texas (where takeoffs
are from almost sealevel and ambient temps may well be over 100F -- fun
to notice your oil temp already reading before you start the engine). I
like to keep my CHT's below 400 or so, even in climb (and more like 330
for cruise). But only a few times, usually a LONG climb at gross, have
I needed to cruise climb for temperatures (I may do so anyway, but
that's just for efficiency).

I don't have an intercooler, and don't have any problem at 75% power, or
even higher (when LOP) during cruise. Interstingly enough, the highest
EGT readings will be at lower power, down around 55%, where 1550+ may be
common (CHT's will be low). And during a climb sometime, try this
experiment - try both 65% or 75% power, vs. full power. I'll bet you
will find that climbing at 41" is a LOT cooler (both CHT and EGT) than
climbing at cruise power.

-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

[Gene Seibel]

"O. Sami Saydjari" > wrote in message >...
> I talked to TCM today to register that I am the new owner of one of
> their engines. Just in passing, I mentioned that their engine failed
> recently within a few hundred hours after major overhaul. They seemed
> completely uninterested in knowing this fact. I asked if they kept
> actual statistics on actual dependability of their engines. She said
> that they did not, to the best of her knowledge. That seems quite odd.
>
> Where do they get TBO numbers from. I always assumed there was some
> serious historical statistical date to back these up. Does anyone keep
> these statistics? Perhaps A&Ps report such failures? Overhaul shops
> maybe? I sure hope someone is tracking the information.
>
> -Sami
> N2057M, Piper Turbo Arrow III

I supect that in the past there were manufacturers who did studies to
convince the FAA that their engines could be expected to go 2000 vs
their competitors 1200 or 1500, and used this as a selling point. Now
noone has any interest in changing it.
--
Gene Seibel
Hangar 131 - http://pad39a.com/gene/plane.html
Because I fly, I envy no one.

[Aaron Coolidge]

James M. Knox > wrote:

: I don't have an intercooler, and don't have any problem at 75% power, or
: even higher (when LOP) during cruise. Interstingly enough, the highest
: EGT readings will be at lower power, down around 55%, where 1550+ may be
: common (CHT's will be low). And during a climb sometime, try this
: experiment - try both 65% or 75% power, vs. full power. I'll bet you
: will find that climbing at 41" is a LOT cooler (both CHT and EGT) than
: climbing at cruise power.

James, this agrees with what the Mooney people say. They recommend 2700/41"
(or whatever full power is, if you've got an intercooler) for climb, using
airspeed and cowl flaps to adjust engine temps. The theory being that you
will be in the climb for a lot less time, I presume. When you say 41" is
a lot cooler, are you increasing airspeed or maintaing the same airspeed as
in a 75% or 65% climb?
--
Aaron Coolidge (N9376J)

[Jeff]

yes I know, you have all the goodies that are suppose to extend the life of your
engine.

"O. Sami Saydjari" wrote:

> Jeff, I have been flying mine at 65% power....and I have an
> intercooler. -sami
>
> Jeff wrote:
>
> > Everyone I have talked to who has this engine in their turbo arrows always
> > say to not fly over 65% power, if so you will not make it to TBO, the
> > exception is those that have an intercooler installed.
> > I only fly mine at 65% power, so far no problems in the year I have had it.
> >
> >
> > Aaron Coolidge wrote:
> >
> >
> >>O. Sami Saydjari > wrote:
> >>: OK. I have gone back through my logs and compiled the following
> >>: information on my aircraft.
> >>
> >><snip>
> >>I think you may find that the TSIO360 engine is considered one of the
> >>least reliable engines out there. This is what's keeping my from buying
> >>a Mooney 231. I did some research into the "Service Difficulty" reports
> >>that the FAA tracks, in concert with A&P mechanics, and it seems like
> >>the engines just devour cylinders. The SDR info is available on the web.
> >>
> >>From reading many ads for 231 airplanes I have seen most engines have
> >>a top overhaul at 800 or so hours, and a major overhaul at 1600 or so
> >>hours.
> >>
> >>--
> >>Aaron Coolidge (N9376J)
> >
> >

[Jeff]

I fly out of las vegas, as soon as the OAT on the ground gets around 85-90
degrees, I have to reduce power as soon as I can after take off due to the
CHT's nearing redline. I do a combination of climb, then level off for a few
minutes untill the temps come back down, then climb some more, then back to
cruise, plus I do not lean much during cruise, I use about 12.5-12.8 GPH
during cruise.

I have another annual comming up in july, I am hoping to install the merlyn
during the annual.

"James M. Knox" wrote:

> I don't think it is so much a matter of what power as what temperature.
> Reducing power helps with the temps, of course, so...
>
> Watching the JPI EDM float around under various conditions, it's easy to
> see how the cylinder temps can get out of hand, even at 65% power. The
> engine is somewhat tightly cowled, no cowl flaps, and comes (originally)
> with a fixed wastegate.
>
> The Merlyn helps a lot on that, especially here in Texas (where takeoffs
> are from almost sealevel and ambient temps may well be over 100F -- fun
> to notice your oil temp already reading before you start the engine). I
> like to keep my CHT's below 400 or so, even in climb (and more like 330
> for cruise). But only a few times, usually a LONG climb at gross, have
> I needed to cruise climb for temperatures (I may do so anyway, but
> that's just for efficiency).
>
> I don't have an intercooler, and don't have any problem at 75% power, or
> even higher (when LOP) during cruise. Interstingly enough, the highest
> EGT readings will be at lower power, down around 55%, where 1550+ may be
> common (CHT's will be low). And during a climb sometime, try this
> experiment - try both 65% or 75% power, vs. full power. I'll bet you
> will find that climbing at 41" is a LOT cooler (both CHT and EGT) than
> climbing at cruise power.
>
> -----------------------------------------------
> James M. Knox
> TriSoft ph 512-385-0316
> 1109-A Shady Lane fax 512-366-4331
> Austin, Tx 78721
> -----------------------------------------------

[Jeff]

my POH says that you should avoid full power climbs, climb power should be
reduced and to climb at 105 kts or better as soon as you clear any obstacles.

full power climbs put extra stress on the engine and reduces the life of the
engine.

Maybe because the mooney guys like those full power climbs is why they have so
many problems with their engines and why you heard so much negative stuff about
them.
You fly the engine smartly and take care of it, it should take care of you, if
not, as the mooney people know, you can expect to replace allot of cylinders.
Its a good engine when babied.


Aaron Coolidge wrote:

> James M. Knox > wrote:
>
> : I don't have an intercooler, and don't have any problem at 75% power, or
> : even higher (when LOP) during cruise. Interstingly enough, the highest
> : EGT readings will be at lower power, down around 55%, where 1550+ may be
> : common (CHT's will be low). And during a climb sometime, try this
> : experiment - try both 65% or 75% power, vs. full power. I'll bet you
> : will find that climbing at 41" is a LOT cooler (both CHT and EGT) than
> : climbing at cruise power.
>
> James, this agrees with what the Mooney people say. They recommend 2700/41"
> (or whatever full power is, if you've got an intercooler) for climb, using
> airspeed and cowl flaps to adjust engine temps. The theory being that you
> will be in the climb for a lot less time, I presume. When you say 41" is
> a lot cooler, are you increasing airspeed or maintaing the same airspeed as
> in a 75% or 65% climb?
> --
> Aaron Coolidge (N9376J)

[Jeff]

Sami
here is an engine for you, they are working on getting it certified for
certified aircraft, they have a new 200 HP version of this engine
http://www.atpcoinc.com/Pages/Products.html



"O. Sami Saydjari" wrote:

> >
> > What broke on your engine after only a few hundred hours?
>
> I will not really know until the overhaulers take it apart. I should
> know more in a couple of weeks.
>
> > Was it a factory
> > engine or a field overhaul?
>
> TCM overhauled it.
>
> > Was it under warranty?
>
> No.
>
> > Did your mechanic file
> > a Maintenance Report or Defect Report?
>
> We shall see. I will report later, when I know more.
>
> Just to be clear. I am not intending to whine about my particular
> failure, but rather express some concern about the lack of actual data
> being collected that supports decision-making about dependability of
> engines.
> >

[Greg Copeland]

On Thu, 22 Apr 2004 13:50:27 -0700, Jeff wrote:

> Sami
> here is an engine for you, they are working on getting it certified for
> certified aircraft, they have a new 200 HP version of this engine
> http://www.atpcoinc.com/Pages/Products.html
>
>
>

That thing really stresses the need for a "fire"-wall...

Is it meant to be installed in the front of a plane?

[Greg Copeland]

On Thu, 22 Apr 2004 13:47:39 -0700, Jeff wrote:

> my POH says that you should avoid full power climbs, climb power should be
> reduced and to climb at 105 kts or better as soon as you clear any obstacles.
>
> full power climbs put extra stress on the engine and reduces the life of the
> engine.
>
> Maybe because the mooney guys like those full power climbs is why they have so
> many problems with their engines and why you heard so much negative stuff about
> them.


http://www.mooneypilots.com/M20K231_Evaluation_Report.htm

According to this, the "GB" engines ran hot and was considered to be
problematic. The "LB" engines were considered to be good. According to
this review, the bad reputation appears to of been earned and directly
relates to the "GB" engines.

The guy that wrote the review worked as a Mooney engineering test pilot
right around the time Mooney came out with the "LB" engine, so chances
are, he knows what he's talking about.

[Aaron Coolidge]

Greg Copeland > wrote:

: http://www.mooneypilots.com/M20K231_Evaluation_Report.htm

This is the evaluation that I was referring to. Thanks, Greg.

PS, I think the cylinder problems with the 231 were due to (1) lousy
cylinders from Continental and (2) pilots not having an engine monitor
exceeding the redline CHT without realizing it.

For a turbocharged airplane I think an engine monitor is an essential
piece of equipment.
--
Aaron Coolidge (N9376J)

[Jeff]

your talking about 2 different engines.
one they stopped using because of problems.

It is still true, turbo charged engines run hotter then normally aspirated ones, if
you run it full out dont expect to make TBO.

its not the engines fault, its the pilots.


Greg Copeland wrote:

> On Thu, 22 Apr 2004 13:47:39 -0700, Jeff wrote:
>
> > my POH says that you should avoid full power climbs, climb power should be
> > reduced and to climb at 105 kts or better as soon as you clear any obstacles.
> >
> > full power climbs put extra stress on the engine and reduces the life of the
> > engine.
> >
> > Maybe because the mooney guys like those full power climbs is why they have so
> > many problems with their engines and why you heard so much negative stuff about
> > them.
>
> http://www.mooneypilots.com/M20K231_Evaluation_Report.htm
>
> According to this, the "GB" engines ran hot and was considered to be
> problematic. The "LB" engines were considered to be good. According to
> this review, the bad reputation appears to of been earned and directly
> relates to the "GB" engines.
>
> The guy that wrote the review worked as a Mooney engineering test pilot
> right around the time Mooney came out with the "LB" engine, so chances
> are, he knows what he's talking about.

[Jeff]

the cylinder problem is due to how people are flying the plane.

I have a turbo charged plane, I fly it a certain way, I do 50 hour oil
changes and oil analysis.There is no way in hell I would fly it wide open.
If you try to fly it like a normally aspirated engine your only asking for
problems.


Aaron Coolidge wrote:

> Greg Copeland > wrote:
>
> : http://www.mooneypilots.com/M20K231_Evaluation_Report.htm
>
> This is the evaluation that I was referring to. Thanks, Greg.
>
> PS, I think the cylinder problems with the 231 were due to (1) lousy
> cylinders from Continental and (2) pilots not having an engine monitor
> exceeding the redline CHT without realizing it.
>
> For a turbocharged airplane I think an engine monitor is an essential
> piece of equipment.
> --
> Aaron Coolidge (N9376J)

[Greg Copeland]

On Thu, 22 Apr 2004 18:28:53 -0700, Jeff wrote:

> your talking about 2 different engines.

Yep. I thought I had made that clear. I'm sorry if I managed to confuse
anyone.

> one they stopped using because of problems.
>
> It is still true, turbo charged engines run hotter then normally aspirated ones, if
> you run it full out dont expect to make TBO.
>
> its not the engines fault, its the pilots.

I assume that statement is squarely targetted at the "LB" engines and not
the "GB" engines?

[Doug]

Aviat Husky. Aircraft started service in Jan, 1997. Currently 2065
hours. Engine not using oil, has good compressions, oil analysis
indicates no problems. Makes power like when new. Engine has never had
any work does on it's internals. Valve covers have never been off.
Note it has been flown often, about 300 hours a year.

[James M. Knox]

Aaron Coolidge > wrote in
:

> When you say 41" is a lot cooler, are you increasing airspeed
> or maintaing the same airspeed as in a 75% or 65% climb?

Constant airspeed (Vy or Vcruise) in the climb.

--
-----------------------------------------------
James M. Knox
TriSoft ph 512-385-0316
1109-A Shady Lane fax 512-366-4331
Austin, Tx 78721
-----------------------------------------------

[Richard Kaplan]

> wrote in message
...>

> What broke on your engine after only a few hundred hours? Was it a
factory
> engine or a field overhaul? Was it under warranty? Did your mechanic
file
> a Maintenance Report or Defect Report?

It only had 314 hours in 14 years? Then failure is no surprise at all.


--------------------
Richard Kaplan, CFII

www.flyimc.com