MMO Marvel Mystery oil Brings down Piper Aircraft

[fdcg27]

As a pilot, you should be well aware that NTSB's findings of "probable cause" are often flaky.
Do you read "Flying"?
Peter Garrison regularly deconstructs NTSB findings in ways not flattering to the agency.
I tend to lend creedance to the thoughts of a pilot who has designed, built and flown two aircraft, as well as developing his own lofting software.

 

[Nitrox]

The NTSB is definitely not a joke of an agency. I've known a couple NTSB investigators, and they all had extensive flight experience, as well as advanced engineering degrees. A family relative of mine was a naval fighter pilot, commercial airline pilot, an aeronautics engineering professor, then went into the NTSB.

 

[expat]

Quote; Examination of the engine revealed low compression on all cylinders, ranging from 44/80 to 5/80. Air bypass was noted on all exhaust valves, and on two of the intake valves. The number two cylinder was removed, and evidence consistent with detonation was found on the surface of the piston, and on the valves.

Was the Octane of the fuel in ALL the Tanks tested?
Were the Valves Bent?
When was the last engine inspection?

 

[demarpaint]

I know nothing about aircraft engines, so please go easy on me.

What does adding something to the fuel have to do with compression testing, and low readings? In a car engine there is a chance that TCW3 or MMO added to the fuel could make a tighter ring seal raising compression slightly in a tired, worn engine, certainly not lower it. Seems to me like this engine had some issues someone was trying to fix....

Again I know nothing about aircraft engines.

 

[Mystic]

Well, you can't really say that MMO brought the aircraft down. If someobdy mixed too much in that is human error or even deliberate on somebody's part. And if only approved fuel and lubricating oil can be used then somebody did not follow regulations.

If there were prior engines issues that somebody was trying to fix using MMO I would not try something like that with an aircraft. I would want to get the engine fixed properly. It is more important for an aircraft engine to be running properly than an automobile engine.

 

[expat]

I guess that adding MMO (as a large%) could lower the octane of the fuel (Lube oil typically has a lower octane rating than Gasoline) this could be critical on a high compression Aircraft engine.
Pre-ignition could, possibly, Bend Valve stems and/or Break the Lands between piston rings.
But more likely this engine was just not maintained/serviced in the correct manor. AND THAT'S WHAT SHOULD BE IN THE REPORT!

 

[dwendt44]

IIRC, avgas is reddish pink in color to begin with.

Lard is an animal fat and is, or at least can be, used in lubrication formulas for many applications.
The GM blower lub is largely animal fat.

 

[Spyder7]

The investigation may be closed, but it still raises many questions. We know that an empty gallon MMO bottle was found in the trash and that, at minimum, the person who added it, added a dose at least 4x higher than what Marvel recommends. We also know the engine showed signs of either excessive wear and, or, internal damage.

We don't know the maintenance history of the engine, or the degree to which MMO was used on it in the past (as in this may not be the first time an MMO OD was given to it). In short, there is too little information to conclude that MMO was the cause, or even a factor in the plane crashing. All we know is the engine failed, and on its final flight it was dosed with 4x the amount of MMO.

Bluestream, you say you are a pilot. As a pilot, you should know the importance in measurement involved in all calculations, particularly those related to fuel. And given this, you should also realize that adding 4x the amount of MMO recommended is way past any fudge factor, and amounts to gross negligence on someone's part.

The only thing I can conclude from what we know is that if MMO played any role (a big if still), it was not simply the addition of it, but the massive OD of it that far exceeds the recommendations of marvel. This in no way reflects upon the product itself; it does reflect on the competence of the person who added it though.

-Spyder

 

[demarpaint]

Still no one explained to me how MMO tied into lower compression readings? IMO that engine had issues someone was trying to resolve.

 

[Spyder7]

This is the most likely explanation in my opinion too. And thinking that if a little MMO is good, a lot must be better, they did the 4x OD - for who knows how many flights before its final one. MMO, IMHO, was incidental to the crash, and that it was present, even at a 4x OD, doesn't prove it caused the crash.

Yet if anything at all were attributed to it, I would attribute it to the person who put in the mega OD and not the product itself. Same as I'd do if someone came on here stating their engine had grenaded after adding 4x the dosage; I would immediately assume a prior condition they were treating with the OD, and dismiss their post for their failure to follow directions and then blame the product for the problem.

If someone overfilled their sump with 4 quarts of Mobil and caused damage, then posted about it in the PCMO forum and blaming Mobil and calling it a [censored] product, they'd be laughed off the forum. Same applies here.

-Spyder

 

[expat]

Originally Posted By: demarpaint
Still no one explained to me how MMO tied into lower compression readings?


Any explanation would be a long shot.
Not enough info on the engine or properties of MMO in an extreme dosage.

 

[demarpaint]

I'm trying to wrap my head around it and can't. An increase maybe, decrease????????????? But then again I know nothing about those engines.

 

[edhackett]

100LL is blue in color. The old 80/87 that is no longer available was red.

These engines are extremely sensitive to octane rating. Filling the tanks on a plane that called for 100/130 with 80/87 could result on a crash at the end of the runway on takeoff with a totally destroyed engine.

It is very possible that too much MMO could lower the octane of the fuel to the point where the engine would be destroyed by detonation. Severe detonation will destroy these types of engines in seconds/minutes. Without seeing test data on the fuel in each tank, we won't know for sure. The engine damage reported is consistent with detonation damage.

Ed

 

[rslifkin]

If enough MMO was added to lower the octane to the point of detonation, it's possible that the rings were cracked, or valves were damaged, causing the low compression.

 

[demarpaint]

Originally Posted By: rslifkin
If enough MMO was added to lower the octane to the point of detonation, it's possible that the rings were cracked, or valves were damaged, causing the low compression.


Now I understand, how the compression could be lowered, caused by damaged rings and valves. Aoocrding to Rich Kelly the MMO tech guy at Turtle Wax, MMO is octane neutral. So the dose must have been extremely high.

 

[Loobed]

One more thing to add

The Piper PA-18 is a 1949 design. I doubt it had computer controlled fuel injection to compensate for altitude. I know someone who has his own small plane. He said he has to manually adjust the air fuel mixture from inside the plane as the air temp changes, or as he changes altitude. He has temp sensors on the heads or exhaust so he knows what is happening. If he doesn't watch the temp gauges and adjust the fuel mixture the engine will either run rich or lean. If it runs lean, the engine will burn a piston or valve.

Just because someone has a pilots license doesn't mean they are a genius. I think it is pilot or management error. It is up to the pilot to make sure his plane's maintenance service is up-to-date. The mechanic can't fix what he doesn't know about.

http://en.wikipedia.org/wiki/Piper_PA-18

I would not run MMO in my engine and I am not trying to claim MMO is good for an engine. I just don't believe in blaming a product of causing engine failure and a plane crash when it didn't.

 

[Spyder7]

That's the cool thing about this thread: many who have contributed to it are not MMO users and don't intend to use the product, yet the vast majority are recognizing that a 4x OD of the product and the question marks surrounding the maintenance history and prior MMO history, raise too many flags to simply conclude that its proof of MMO being a bad product capable of destroying engines.

Instead the vast majority are recognizing that given the questions still raised, and what we know which is that a 4x OD was given on the final flight, is not proof that MMO is itself to blame.

-Spyder

 

[expat]

Another point;
Quote: "The operator told the FAA inspector that the red color was from an additive placed in the fuel tank, at a rate of one quart for each refueling."

Was the tank empty at each refueling??
If not the % increase of MMO in the fuel could have been progressive!

 

[demarpaint]

Originally Posted By: expat
Another point;
Quote: "The operator told the FAA inspector that the red color was from an additive placed in the fuel tank, at a rate of one quart for each refueling."

Was the tank empty at each refueling??
If not the % increase of MMO in the fuel could have been progressive!


Good catch!

 

[Boss302fan]

Stupid... MMO works great when it is used by someone that can read.