ECI Cylinder AD: The More You Look, the Worse It Is

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Hereís my definition of a bad day: You overhauled your Baronís IO-520s† a couple of years ago using cylinders from ECI and now the FAA would like you to remove those jugs and replace them with something else. Round it off and call that about $25,000.

Thatís the basic gist of a proposed airworthiness directive the FAA announced two weeks ago and about which weíve been reporting regularly. The AD targets about 30,000 ECI cylinders of various vintages for two kinds of cracking: a failure in the shrink band that holds the head to the cylinder barrel via an interference fit and cracking in the dome of the head. Both flaws can result in catastrophic cylinder failure, but †not necessarily complete engine failure.

On this much, the FAA and ECI agree, but they see eye-to-eye on little else. They donít agree on the number of actual failures in the fieldóthe FAA says more than 30, ECI says it can confirm 19. Nor do they agree on the failure mechanism. In the AD documentation, the FAA says it doesnít know what the failure modes are, just the results, while ECI insists that the head/barrel separations were caused by overheating due to pilot engine mismanagement. Maddeningly, the governmentís own NPRM process precludes the FAA from supplying specific information on its methodology or the underpinnings of its conclusion to demand removal of these cylinders. The AD docket gives some information, of course, but ECI says it has a lot of questions the FAA isnít answering.†

In my view, no reasonable person could look at the available dataóa combination of Service Difficulty Report analysis, field reports and in-house manufacturing historyóand feel confident of having an accurate picture of reality. In short, the data is just too sketchy. It may be biased toward classifying failures that arenít head/barrel separations or it may very well miss many that are. I'm not sure you can tell which is which from reviewing the data.

Taking the broader view from this too vague compilation of dodgy numbers and unsupported theories, ECI concedes this: When compared to Continental Motors OEM cylinders, its incidence of head/barrel separation is much higher, although just how much higher we donít know. They donít either because they donít have accurate numbers for the Continental OEM cylinder population. ECI says it has about 25 percent of the cylinder market and during the period 2002 to 2012, ECI insists it had 19 verified head/barrel separations compared to 24 for Continental on the same 520/550 cylinders. The raw data ECI provided us showed 36 failures, but the company says many of those were unverified or improperly classified. † †

Just to grasp at some kind of solid foundation in a field of numbers that just donít add up, letís accept ECIís 19 failures. As these things go, thatís comparable to the Continental record, except for one thing: it applies to a much smaller population of cylinders, so the rate of failure is at least twice as high, but could be four or more times as high, depending on whether ECIís estimate of its cylinder market share is accurate. On a rough per engine basis, the 30,000 ECI cylinders under the gun represent 5000 engines, meaning that with 19 incidents, the per engine rate is one failure per 263 engines. For Continental engines, the rate is much lower, perhaps as much as four or more times lower.

Isnít that damning for ECI? It certainly doesnít look good. Thereís got to be some explanation for ECIís higher failure rate. And there is, but first, letís put things in perspective. Worst case, at least from the data we have and with the caveats Iíve described, the percentage of ECI cylinders with head/head barrel separations is 0.12 if you accept the FAA data and about half that if you take ECIís data. Moreover, ECI's data shows a declining incidence of head/barrel separations, with none at all during the past two years. Its statistical analysis suggests the separations are in decline in the target cylinder population.†

While itís true that these rates and percentages are worse than for Continental cylinders, we are still talking about very small risks indeed. Could it be that there have actually been many more ECI head/barrel separations than have been reported? Maybe, but if thatís so, why havenít any of the six engine shops I canvassed two weeks ago seen them? It seems reasonable that if thereís a breaking wave of heads flying off of barrels, at least some of the shops would know about them. They donít seem to. Nor have we heard from any readers with direct experience following the ECI story.

†As I†reported two weeks ago, what some of the shops have seen is what I call pedestrian crackingócracks around fuel injector bosses, spark plug holes and the like. Some shops think ECI cylinders are more susceptible to this and have stopped recommending them, but thatís an entirely different consideration that has nothing to do with head/barrel separations.

So against this backdrop of uncertain data and a small risk, the FAA proposes the potential of an $83.3 million AD to selectively remove these cylinders from service, the cost to be borne entirely by owners. Given the weakness of the data and the small numbers, this is obviously hitting a small nail with an exceedingly large hammer. Absent better data from the FAA, I just donít see how this AD is justified.

But thatís not to say nothing should be done. ECI doesnít challenge the fact that Continental OEM cylinders have a much lower rate of head/barrel separation. Their explanation for this is that their cylinders live in a different market segment thatís heavy on older or aftermarket applications in which pilots donít have sophisticated engine monitoring and are thus more likely to mismanage engines and thermally stress their cylinders, which ECI says is the failure cause, not manufacturing or quality issues. When I visited ECI in San Antonio last week, they showed me data that clearly showed how cylinder mating threads are stressed by over temping, with the load curve heading straight up above 450 degrees or so.

But Iím not quite ready to buy this argument, frankly. Plenty of Continental OEM cylinders go on older Bonanzas and Cessnas and thereís no reason to believe the pilots of those airplanes are any more or less hamfisted with the mixture knob than are ECI cylinder buyers. And ECI doesnít have the electronic data from any cylinder failure events to correlate the theory in the real world.

Bottom line, ECI cylinders fail at a higher rate, but not so high as to represent meaningful additional risk worthy of the FAAís massive AD. †The risk here is too small for the FAA to wade in and dent owners with this kind of overbroad, expensive AD. While the FAA has a duty to protect the public safety, it should do so reasonably and with cost in mind. Small or marginal risksóand this appears to be in that categoryóshould be left up to aircraft owners to judge and mitigate. In my view, a non-mandatory service bulletin that summarizes the data and advises †owners of the failure pattern and rate and how to inspect cylinders for potential cracks seems the fair way to approach this. Owners can then make their own risk/cost assessments, which is what owning an airplane is all about anyway. Then watch the situation for a couple of years and revisit as necessary. Otherwise, the AD ought to be dropped for now.

You can read and comment on the docket here.

Join the conversation. †Read others' comments and add your own.

Comments (20)

We have ECi cylinders on our parachuting aircraft (C185 : IO-520D) and are happy to state that in just under 700 hours in service with this engine, we have not had to have any work done to them what so ever. The oil samples are coming back with grade "A" reports at every 50 hours (with just one grade "B" some while ago after the aircraft sat idle for the best part of sie to seven months). Plugs alway have very little to no lead at each 50 hours check and thus, valves and guides have needed no attention in this 700 hour period!

We also have a JPI EDM930 fitted which enables us to acurately keep the CHT's to no more than 380 degrees C and fuel flow turned-up an extra 1.5 USG/hr for take-off etc. Agressive 'leaning' is used for all ground manouvres, with the mixture control basically left where it is at the top of climb for the whole descent! EGT's are kept to no more than 1,330 degrees C in the climb at between 80knts, reducing to 75knts at altitude.

Oh yes! ..... leak down tests on last check were 3x 80's, 2x 79's and 1x 78 ... which is fairly consistent on all checks. Incidently, on the previous engine with factory cylinders fitted, three were removed for valve/guide work within the first 400 hours and five had work to them by the end of it's 1,800 hour life. (In fairness, the JPI EDM930 was not fitted at the time).

Steve Holder
New Zealand

Posted by: Steve Holder | August 29, 2013 7:32 PM    Report this comment

The lesson might be to make sure that digital engine management readouts, giving readings for each cylinder, be installed when ever new heads or cylinders are needed so pilots can avoid overheating (and save fuel).
Of course that would be possible only if their price was not so inflated due to FAA certification requirements.

Posted by: John Patson | August 30, 2013 5:27 AM    Report this comment

The company I used to work for operated 10 twin Cessna's - I believe we had 2 ECi head separations - otherwise no complaints. My impression, the ECi's may be slightly more prone to head cracking, but is less apt to have valve problems, so at the end of the week I'd buy them. I have ECi Titans on my Continental powered 172 (I know different engine application) and love them - at 800 hours, zero issues and compressions 79/80.

Posted by: Josh Johnson | August 30, 2013 5:41 AM    Report this comment

ECI had issues with their Titan cylinders for the O-540 a couple years back. There was an AD, and I think that one was far more reasonable, requiring inspections of the cylinders every 50 hours an hour limit on a subset that were determined to be the most likely to fail, and mandatory retirement at TBO (I hope I got that right). I had put a set of those cylinders on my Cherokee Six, and I specifically selected the Titans for the superior corrosion resistance. Those cylinders are still on the airplane, running quite fine and the frequent inspection is a relatively minor cost for some peace of mind. Why the FAA can't allow frequent inspections, perhaps borescope inspections for cracks as well, and maybe even mandate an engine monitor, all of those would be far cheaper than a wholesale replacement that may precipitate other failures.

Posted by: RAY ANDRAKA | August 30, 2013 6:38 AM    Report this comment

Of the three aircraft using TSIO 520 NB engines on our field using ECI cylinders, one has had 100% of it's cylinders replaced prematurely, one 60% and the other 1 cylinder. Non-were by the barrel/head but rather by the fuel injection and leaking fuel. The replacement cylinders were of a different casting design to allow improved feed metal during the casting process.

Posted by: HAROLD J WORKMAN | August 30, 2013 7:31 AM    Report this comment

Good analysis Paul. For something this major, why doesn't FAA have an AMOC like inspections? This has been commonly done in the past for other ADs. If this type of broad but weakly-identified AD is a new tack by the FAA I'm afraid we could all be grounded soon. Let's hope not.

By the way, the 0.0012 figure is the fraction of failures, not the percentage (0.0012 = 36/30,000). The percentage would be 0.12%. Just words, but important ones.

Posted by: A Richie | August 30, 2013 9:56 AM    Report this comment

I am an A&P / IA, and your article fails in several respects:
a) allowing owners to choose and decide? Owners are generally unable to technically decide and will typically base a choice on cost - and if they have the choice they'll say "They've been fine, leave them alone" and do nothing;
b) the failures are catastrophic. Means sudden, without warning. They come apart at the identified zone of weakness.
c) the past incidence is indicative, and will continue. The fatigue failure incidence is past and the future can expect the same rate or higher as the fleet TIS grows;
d) Your premise that the failure of a cylinder may not lead to total engine failure is a presumption and appears reckless. Any element of failure, especially a cylinder failure, is a major failure.

The FAA is a regulator and has laboratories that can conduct metallurgical testing, and can evaluate risk. I trust their analysis over that of an aircraft owner. As a regulator they are charged with the responsibility of exactly that. Their only tool is to modify data, but in this case there is no modification of the existing cylinders available, so it's a choice of replacement or persevering with the existing latent problem.

I suggest that you reflect these responsibilities in your otherwise excellent article.

Posted by: Pat Barry | August 30, 2013 10:21 AM    Report this comment

"Owners are generally unable to technically decide and will typically base a choice on cost."

To which I would reply, what's wrong with that? Aircraft ownership is a constant balancing act between what you spend and what you get. Suppose the FAA came along and said you must install active traffic equipment because it will improve safety. Would you then say we have to follow the regulators directive just because they are regulators?

In this case, the FAA has not demonstrated a high degree of risk, only a pattern of failures that appears to be somewhat worse than competitors. As for the increase in failures, ECI insists the reverse is true: this population has shown an attenuation in incidents as fleet hours increase.

I keep coming back to the relative risk, which appears trivial. We the regulated should have a say in how the regulators make decisions which impact cost of ownership. The FAA hasn't demonstrated a clear and present danger to flight safety or the general public from airplanes falling out of the sky.

They may get there, but they haven't yet.

Posted by: Paul Bertorelli | August 30, 2013 11:17 AM    Report this comment

"Owners are generally unable to technically decide and will typically base a choice on cost."

To which I would reply, what's wrong with that?"

What's wrong with that is the FAA is entrusted with the task of protecting the general public. Owner decisions can be all over the map. I might decide that carrying my grandchildren in my twin with ECI cylinders is not acceptable, and have them replaced. Guys across the field running charters into ski country with 414s might try to eek out another marginal season with what might be a ticking time bomb, or not. Should they make the decision? What are their qualifications for doing so? Who should really decide how to protect the public?

Posted by: Edd Weninger | August 30, 2013 5:26 PM    Report this comment

Does lean of peak operation and not monitoring CHTs a factor here?

Posted by: Dave Jaundrill | August 31, 2013 7:03 AM    Report this comment


That is an easily solvable issue, and it can be handled the same way the FAA deals with all things related to the difference between part 91 and part 135/121.

Make inspections and/or replacement mandatory only for commercial operations (even if part 91). Add a carve-out for flight training and private rental.

Now, anyone carrying passengers or cargo for hire needs to have the extra caution that you're describing, thus protecting the public. Owners and flight schools are still free to do as they see fit.

Posted by: Joshua Levinson | August 31, 2013 2:12 PM    Report this comment

Further, doesn't the FAA have to prove there's clear and present diminution of flight safety here, whether applied to for-hire or Part 91 operations? And if so, has it?

I'm far from convinced.

Posted by: Paul Bertorelli | September 1, 2013 6:37 AM    Report this comment

A regulator's strongest tool remains bad publicity.

I haven't found anywhere what ECI is planning to do to ensure these cracks don't occur going forward.

Paul you state: Maddeningly, the government's own NPRM process precludes the FAA from supplying specific information on its methodology or the underpinnings of its conclusion to demand removal of these cylinders.

Couldn't figure out what exactly additional info you were referring to. The FAA regulatory process has a pretty good track record and is pretty robust. However, what I couldn't find in my short look thru the docket is the cost-benefit analysis that is typically required. At 80+ million, 5.7 million per life (DOT policy last time I looked) they must be estimating around 15 lives. But that analysis should be part of the docket. That's not a hard requirement and sound judgment can override the data but again that logic should be part of the docket.

Posted by: Rob "daSlob" Schaffer | September 2, 2013 8:21 AM    Report this comment

"Couldn't figure out what exactly additional info you were referring to."

I can be specific.

As they are required to do, the regulators are asking for comments on the NPRM, which presume they are seeking opinions. One needs data and facts to form same, plus answers to questions. My chief question is this:

We think the FAA used two statistical models to predict head-barrel separations in the named cylinder population, one called Weibull, the other Crow-AMSAA. Between these two projection methods and the two cylinder populations, the total head/barrel separation events were supposed to be about 50 between 2011 and 2013. But none occurred, according to ECI. None have occurred in cylinders manufactured since 2008, says ECI.

So my question is: did these models underpin the FAA's decision to broaden this AD? And if they did, what input assumptions were made? And why is the prediction so divorced from reality and shouldn't this be a consideration in asking for such a broad remedy? As you know, government NPRM rules preclude these discussions.
They should not.

As for 15 lives, there have been no accidents, fatalities or injuries related to these cylinder problems. Maybe I just dense, but I couldn't find this in the docket and neither does ECI say it's there.

It just seems that this is a lot of money, effort and disruption to perhaps correct a small problem. And let's not forget the potential for introducing problems when opening up 5000 engines and replacing cylinders.

To me, the numbers just add up in an action where the FAA admits it doesn't understand the mechanism for these failures.

Posted by: Paul Bertorelli | September 3, 2013 1:54 PM    Report this comment

The lack of the statistical analysis of the failures doesn't particularly surprise me - AD's are issued (proposed) when the FAA determines an unsafe condition exists, not the public, and sometimes includes proprietary data. Though I would of thought ECI had visibility to them. Personally, I don't believe their data to be overly conservative - too many operators of light airplanes don't report problems they just fix them and how does one account for that in ones analysis.

So while they probably welcome any comment, they specifically want comments on the regulatory, economic, environmental, and energy aspects of the proposal seems like an aviation consumer magazine might post comments on behalf of the consumers to question the FAA's regulatory evaluation e.g:
-How did the the FAA determine that this proposed change is not a significant regulatory action under Executive Order 12866? That the cost of this change is significant to this segment of the industry reaching across a large number of aircraft. So a cost benefit analysis should be conducted taking into account DOT treatment of the value of preventing fatalities and injuries in preparing economic analysis and OMB policy and the spirit of the Presidents Order.
-How did the FAA determine that only 6,000 engines would be impacted when clearly not everyone replaces every cylinder so the impact to the number of consumers is far greater and the FAA's analysis should take into account.
-The 82+million estimate doesn't account for lost revenue/time on the products, particularly since a portion of these engines are used for commercial operations. This should take into account however many weeks the airplane will be down for inspection, removal, replacement of any cylinders and the amount of revenue these airplanes won't generate. I could easily see another 20 to 30 million in costs to the industry but that is something those who use these engines need to pony up;
-How did the FAA determine that there would be no impact on interstate commerce in Alaska when clearly these engines are installed in aircraft used for commercial use where aviation is the only means of transportation in Alaska (examples warranted).
-Also it is hard to believe the AD won't impact any number of businesses that qualify as small and entities
-That when the above is provided by the FAA the public should be afforded 90 days to review and comment prior to proceeding with issuance of any AD.

Posted by: Rob "daSlob" Schaffer | September 3, 2013 8:01 PM    Report this comment

19 (or 30) head/barrel separations? Wow. I guess I have really bad luck. The twin Cessna I was flying from 2001-2010 had 3 in flight head/barrel separation, AFTER having all 12 cylinders replaced under warranty due to a proposed AD that later went into effect. We also caught 3 more head/barrel separations on the ground with inspections we started doing every 50 hours. Each of these cylinders was replaced under warranty, so I would assume they became part of the data pool. After 6 failures, we lobbied the engine installer for an entire new set of non-eci cylinders, which we got. We had no further problems.
After the first 2 in flight failures, we installed an engine monitor. While operating the engine under the same parameters as before the failures, we found cylinder head temps did not exceed 410 in any phase of flight, yet we opted to run even more fuel and with cowl flaps open slightly to keep cylinder head temps below 400 (alarms were set on the engine monitor to help ensure this). Yet we still had 4 more failures. And after the third full set of cylinders were installed (ECI overhauled Continental cylinders), we had no more problems with any cylinder cracking. These cylinders had about 500 hours on them if I remember correctly.
In flight failures cause a lot of vibration. While the engine may still produce some power, it might also damage something with the vibration if operated very long. I opted to shut it down each time. Thankfully I had two engines. If I had been in a P-210, this would have been a major emergency. This experience led me to believe I no longer want to fly in turbocharged single engine planes.
In one of the in flight failures, the separation was so severe, it tore the baffling and bulged the cowling. During this time, another operator on the field had a separation where the head went through the cowling and departed the airplane, however I never heard if his was an ECI cylinder.
We spent a lot of time with the engine shop trying to figure out why this kept happening. They had no issue with the manner in which we operated the engine. The cylinders apparently bore all of the blame.
That being said, if they have fixed the problem and there have not been more failures, why the AD? On the other hand, I find it hard to believe I represent 20-40% of all of the failures, depending on which data you look at. It seems there may be a good bit of under reporting going on.

Posted by: WILLIAM BEEVER JR | September 4, 2013 5:17 AM    Report this comment

I was flying an A36, and had just gone wheels up, when the cylinder head on the #3 (ECI) cylinder separated from the barrel. It caused a lot of vibration and reduction in power. Outside of that, no other issues. I was able to maintain altitude at pattern altitude so I decided to go ahead and lower the gear and continue through the pattern with constant eye outside to find a place to put it down if the need arose. I was able to fly a full pattern and land without incident. Now to address the total number of reported head/barrel separations. In reading through these (at the time) 16 comments, I am counting a total of 15 (including my one) issues with ECI cylinders. With a sample size 16 accounting for 78.9% of ECIs claim of 19 cylinder issues, I suspect that the FAAs count is a bit more accurate, if not conservative itself.

Posted by: russell schrock | September 4, 2013 9:32 AM    Report this comment

A club I flew with in the mid-90s had four ECI cylinders have head/barrel separation on three different aircraft resulting in three forced landings, one of which was off-airport. The forth failure was detected during run-up.

Do other manufacturers have issues with head/barrel separations? It seems that the shrink fit heads inherently puts high stress on the head/barrel.

Posted by: John Clear | September 4, 2013 11:46 AM    Report this comment

Historical evidence suggests that plated cylinders have a greater propensity to suffer head-to-barrel failures in the thread-engagement area than non-plated cylinders-regardless of manufacture. Acid etching of the barrel prior to plating has been shown to generate corrosion in areas made difficult to clean-specifically, the threaded portion of the head. This corrosion compromises a highly stressed area resulting in head separation. If failure analysis identifies the alloy as the root cause, justification for the AD exists. If, however, the plating process is to blame, the remedy is simply procedural.

Posted by: Paul Brevard | September 11, 2013 4:08 PM    Report this comment

I own an A-36 Bonanza with ECI cylinders on a reman engine from RAM. Just got a call from my IA that 2 cylinder heads are cracked. There are 700 hours on the engine and everything has been fine up until now. I have a GEM gauge and always fly rich of peak. The mechanic pulled the affected cylinders and looked in the engine. Everything looked perfect - other than 2 cracked cylinder heads. I believe the ECI data is really questionable - and I'm now concerned about the other 4 cylinders on my engine. I am a 4500 hour commercial pilot and I take special care of my engine. Full mixture on climbs, no shock cooling on descents, warm up before run up, cowl flaps always open on climb and taxi... Sure seems to me there's a manufacturing problem with ECI cylinders based on all I've read and my personal experience now. I wonder how many more reports of problems were going to see and where this is going to lead?

Posted by: DOUGLAS KAHN | December 14, 2013 2:57 PM    Report this comment

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