The 1965 Cessna 172 “Fox” model was 2,000 feet above the ground after lifting off from Oakland/Troy Airport (KVLL) on the north side of Detroit, Michigan, when it happened. First, the engine shuddered. Then it started to run rough. Airspeed dropped as the RPM rolled back.
About equidistant from his home base and the next nearest airport, the pilot turns back for home. He fiddles with throttle and mixture controls, does an in-flight mag check, then changes tanks. Nothing helps.
When he increases throttle “trying to get a little more thrust” to keep altitude, the engine gets worse. He later told the NTSB, “I knew I was going to have to land off-field.”
He spies a “perfect,” arrow-straight, “less-used road” right as the engine seizes. He makes for it, but he’s too high and overshoots his planned touchdown, landing long and hot — and finds himself fast approaching an intersection with a second road. A road which, charmingly, features a crab apple tree-lined median. As he zips through the intersection of the two roads, the left wing clips the trees and the off-field landing becomes an accident.
The plane veers sharply left, flips on its back, and skids to a stop in a sad little crumble in the median amongst the crab apples, its tail overhanging the road.
The pilot releases his seat belt, falls to the ceiling of the plane, and crawls out the door. As he stands up he sees the exposed belly of the airplane. It is covered in oil.
The Pilot
The pilot was the owner of the 172, and had been for about eight years. At the time of the accident he was 63 years old. He held Commercial-Multi, CFI, and ATP certificates. He had a 737 type rating but was flying under the third class privileges of a two-year-old Class 2 medical. Despite his certificates, he did not list himself as a working professional pilot.
His logbook showed 3,929 hours total time, which is not that many hours for an ATP of his age, suggesting either a late career start, or that he was a victim of industry headwinds during his career.
The latter strikes me as more probable, when thinking about his age at the time of the accident.
He (like me) is a member of the generation of pilots who suffered the “Black Swans” of the Gulf War, the 1990s recession, 911, and COVID. Our generation got hit by so many industry-numbing setbacks that I’m not sure we can really call them Black Swans anymore, but if someone wants to create some sort of Commercial Pilot Black Swan Squadron patch, I’ll proudly wear one.
But back to our hero.
More than 70% of his flight time is single-engine land, with 421 hours in make and model. He only flew two hours in the previous month, but clocked 29 hours within the last 90 days.
The NTSB
When investigators inspected the wreck they noted damage to both wings, the horizontal and vertical stabs, and the top of the fuselage. The windshield was knocked out, the prop was damaged, and the motor mount bent, which is the least of the motor’s issues.
Investigators found a gaping pair of holes in the top of the engine case above the two left-rear cylinders. Consistent, investigators say, with “catastrophic failure due to a lack of lubrication.”
A huge puddle of oil is discovered on the ground outside his hangar and a trail of oil leads down the taxiway, too. Oh, right, and the trail extends down the first part of the runway. You wouldn’t think seven quarts could make such a mess, but it will.
The oil leak is traced to an externally-mounted oil cooler, which had been installed under a field approval. But the cooler isn’t blamed for the oil system failure. Instead, the pilot is.
The Flight
Rewinding to before the accident, it’s early in the afternoon shortly before Christmas, and the battle plan for the day was described by the pilot as “basic proficiency.”
He was headed for the local practice area where he planned to practice steep turns and stalls, then get in a pair of landings on return to home base.
The pilot estimated the outdoor temperature was around 35℉, while weather data gathered by the NTSB at the time of the pilot’s departure put it at 28℉. Chilly, we can all agree, perhaps even freezing, but not crazy cold.
Before pulling the airplane out of its hangar, he rotated the prop 10 times to get the oil moving and lubricate the engine. He told authorities that he did not preheat the engine.
Nor did he, apparently, wait for the engine to warm up, but headed straight for the runway — the departure end of which was right by his hangar — where he did a quick run-up and took off.
He told the NTSB that during the engine run-up and takeoff roll, the engine oil temperature gauge was “not registering.” He didn’t recall what the oil pressure gauge showed.
More NTSB
In its report, the NTSB made a big deal out of the pilot’s cold weather starting technique, which I, too, find fault with.
But in fairness, most of the documents quoted by the NTSB — including a Continental Motors Service Information Letter — dealt with starts of cold-soaked engines below 20℉. And regardless if we believe the pilot or the NTSB investigators about the temperature that afternoon, it was nowhere near that cold.
And while I’m sure many of you are clamoring for the pilot’s head for taking off with no oil temperature indication, if you look at the airplane’s POH for cold weather starts, it does say that you may not get an indication on the oil temp gauge, and that this is perfectly OK.
The POH reads: “During cold weather operations, no indication will be apparent on the oil temperature gauge prior to takeoff if outside air temperatures are very cold. After a suitable warmup period (2-5 minutes at 1,000 rpm), accelerate the engine several times to higher engine RPM. If the engine accelerates smoothly and the oil pressure remains normal and steady, the airplane is ready for takeoff.”
But, of course, he didn’t do that two- to five-minute warm up, so I guess you can go ahead and take his head. Oh, and if you bother to read the whole section, the POH isn’t using “around freezing” for this cold weather ops advice, or even Continental’s 20°. The POH is giving operational advice for temperatures 0℉ and colder!
Additionally, the NTSB report says for outside temps below 40℉, for this airplane, the recommended oil is SAE 20. For temps above 40℉ the proper oil is SAE 40. The airplane had neither.
Instead, the airplane was filled up with SAE 50, which was rated for an operating temperature range of 60℉ to 80℉. Apparently this thicker oil was put in the engine by the pilot that autumn, when the airplane was based in Las Vegas, which might be a perfectly reasonable choice for that environment at that time of year, although maybe not, if not approved.
But wait. There’s more.
The pilot-owner reported that the plane had seven quarts of oil in the sump, and that he had added a half-quart of Marvel Mystery Oil — an oil additive product — to “try and thin it a bit.”
Analysis
So let’s talk about that oil additive, often called MMO. It was invented by Burt Pierce in the 1920s.
You may never have heard of Pierce, but you have heard of his other great invention. He was the inventor of the Marvel Carburetor, which by the time of MMO, was used on an astonishing 80% of vehicles, and a great number of airplanes, as well. But many of his carbs were suffering problems with clogged carburetor jets due the high lead content of gasoline at the time. Pierce’s Mystery Oil was designed as an internal cleaning product to prevent clogged jets.
But as an unintended side effect, it apparently helped with piston setting, resulting in higher compressions and reduced blow-by, making it popular with racers, which in turn led it to become a legendary success as a product.
That, plus the fact that, at the time, no one knew what it was made of (mainly mineral oil as it turns out), fueled more speculation than clean jets, and — as befits a legend — over time, MMO would take on other mystic and mythical powers.
While not “approved” for certificated aircraft engines, MMO has a following in some sectors of GA. I put “approved” in quotes as the FAA doesn’t really approve oil additives, but it does sometimes “accept” them. Acceptance is basically the FAA saying that it can’t see any harm in using it. A good example of an accepted additive is CamGuard.
Now in fairness, MMO perhaps could be accepted, it might simply be that no one has asked the FAA to accept it.
But either way, the view of the engine manufacturer is another kettle of fish all together. Continental, for instance, says use of any additives, FAA accepted or not, is verboten and voids your engine’s warranty.
I’m not sure what the pilot’s logic was in using the MMO additive to thin his oil. But there’s a lot of hangar talk, and hangar experts, when it comes to legendary products like MMO.
Mike Busch, of Savvy Aviation, had this to say about MMO on his website: “Pitchmen have long been promoting oil additives that eliminate friction and wear, increase fuel economy, improve your landings, raise your IQ, and rescue your marriage.”
So why not use it to change the viscosity?
But why not just change the damn oil to the right stuff instead of playing hangar chemist?
Perhaps it was because his plane would be out of annual in a few days. The previous annual, back in Nevada, was signed off on the first of December the previous year. Maybe he knew the new guy would change the oil as part of the inspection.
Busch, by the way, goes on to say that when it comes to MMO, “folks have been pouring this stuff into aircraft engines for more than 80 years.”
Based on his experience, his feeling is that, used in moderation, it “doesn’t do any harm,” but from what he’s seen, “it doesn’t seem to do much good either.”
Needless to say, I didn’t write to ask him what he thought about using it as an engine oil viscosity adjuster.
And to be clear, the NTSB wasn’t laying the blame on the Marvel Mystery Oil, but it basically used the pilot’s use of it as one nail in the lid of his metaphorical coffin, as part of a chain of disregard for the proper manufacturer’s guidance for cold weather operations.
Discussion
The pilot didn’t preheat the engine prior to start, nor did he warm it at low RPM to operating temperature prior to takeoff. He just jumped in, fired up, and blasted off into the wild blue yonder. Well, blasted off into the first 2,000 feet of the wild blue yonder, anyway.
Did he believe the Marvel Mystery Oil would work its mythical magic? Or is this a case of SSOP (Sucky Standard Operating Procedure)? Or did he simply fall back on old habits that worked fine for him in a warmer part of the country? Did time in the airlines somehow affect his GA sense?
And, hey, did his poor oil grade choice, cold start, and lack of warm-up even cause the oil leak, or did the oil cooler fail in some way that had nothing to do with pilot abuse of the recognized and recommended cool weather start-up procedures?
The Takeaway
Just because we may never know the true cause of the oil leak that killed the engine and wrecked this airplane doesn’t mean that there aren’t any takeaways.
The obvious premium takeaway here is to make sure to match your oil to the operating environment. Well, more than your oil really — your standard operating procedures, too. It might be fine in a warm climate to fire and fly, but that doesn’t work in colder climates. If you’ve moved, please adjust your SOPs to your new environment.
Another key takeaway is not to simply read the checklists in the POH, but read the supporting material that is provided with them. Don’t just flip to the “cold weather ops” checklist without knowing how that is defined in the book.”
It really wasn’t cold enough for the oil temperature gauge not to work. It wasn’t registering because there was no oil to measure. Maybe with heightened awareness as to what temperature to expect that acceptable mode of failure, he would have been better alerted to the real problem.
And lastly, while we spend a lot of energy on aeronautical decision making, perhaps we need to revisit critical thinking as a pilot skill. I’m not dissing Marvel Mystery Oil (I like a good mystery as well as the next person) but buying seven quarts of the right oil for the climate strikes me as better critical thinking than trying to make my own home-brew oil.
The Numbers
Want to read more? Download the NTSB’s final report here or view the items on docket here.
MMO swells rubber, we had a case where the seat gasket of a spin-on oil filter swelled and blew out dumping a lot of oil very quickly.
MMO was used in WW2 by the 50 gal. drum in big radials to scavenge lead out of the combustion chambers.
If you get a chance place a piece of rubber in MMO and see what happens.
The two to five minutes warm up is not much warm up and likely the time from the hanger to the mag check to the runway was two to five minutes. With this additive documented used for what a hundred years and no issues tells me that the CYA part of not using it is all that is CYA. The 50 weight at the time of the failure likely had some wear due to the assumption that checks and maintenance were due. That oil likely was not the viscosity of new 50 weight and more closely resembling something under new 40 weight. So, the flight operating performance of the engine likely would not have shown degradation if the engine got a full quantity of this lubricant. So, the focus is that the lubricant was missing from the engine. Why? And could a reasonable pilot have noted this in a proper preflight? Why did the oil cooler assembly reject the engine oil? That is step one of the root cause analysis in the answering of the mechanical whys. Why did the plane crash – it lost power. Why did the airplane lose power – it’s engine catastrophically failed. Why did it’s engine catastrophically fail – it wasn’t getting oil. Why wasn’t it getting oil – it’s oil cooler assembly had an unconstrained failure. Why did it’s oil cooler have an unconstrained failure – [NTSB response {the root cause of the incident} goes here]. All other things are not the root cause, they are contributing causes. The pilot didn’t recall the oil pressure didn’t cause the engine to fail. He could have stopped attempting flying and towed the airplane back to the hanger. The accident would have been just delayed unless you assume he had the oil cooler assembly failure and he could have noticed it. The oil cooler assembly failure was the root of the problem and the NTSB did not address that in this article.
OMG. Really astonished with the debate on all this. As the oil leak originated from the oil cooler, that was the problem that led to the engine failure. So the guy didn’t let his engine warm up enough, But I could almost guarantee you that the burst strength of the oil cooler is gotta be way more than what an engine could put out with cold oil. Not a big proponent of Marvel mystery oil, but doubt that had anything to do the oil starvation!
A story in 2 parts;
– he trashed the engine with a cold start with the wrong oil.
– he botched the off-airport crash.
I doubt that the MMO had any affect
So, more stupid pilot tricks.
Wow…this story has some “legs”! I’ll admit; it is kind of a head-shaker. Our pilot had plenty of chances to “break the chain” and prevent the accident. But instead, he kept adding links to it.
That includes not just the events that led to his engine letting go, but also his admittedly botched attempt at an emergency landing. As already noted, if he hadn’t hooked his wing tip on that tree, we wouldn’t be here…
As far as the MMO/50wt oil cocktail in his sump;
I wonder how much mixing and “lubrication” he thought he was going to accomplish by pulling his prop through by hand “10 times”?
I flew a 170B in Fairbanks for years, including during the winter; it was always kept outside. Regardless, I always just used the correct oil for the temperatures…plus extensive pre-heating when required.
I followed the very limited POH guidance for cold wx ops, and never had an oil psi/temp issue. However, I did turn a couple Gill batteries into frozen bricks.
OTOH, I’ve seen some very experienced guys, while flying in the real Alaska (that’s north of the Alaska Range…not the balmy Anchorage suburbs), mix MMO with their Phillips 66 X/C or AeroShell oil at almost a 1:1 ratio and never have an issue.
Hhmmmm? Maybe it WAS his “Arctic Blend” that helped keep the engine from coming apart even earlier? Like during his full-throttle takeoff & climb out.
No mention of him “hearing” anything unusual, like a really loud bearing knock? He must’ve been wearing a high quality noise-canceling headset!
Anyway;
This “Black Swan” dissertation confused me a little bit:
“His logbook showed 3,929 hours total time, which is not that many hours for an ATP of his age, suggesting either a late career start, or that he was a victim of industry headwinds during his career.”
Apparently, his age, ratings and experience don’t quite add up for some reason?
Even though this guy goofed, I’ve learned to never judge the competency of a pilot based solely on their seemingly-limited flying hours. You never know what they included. (He’s got a 737 type rating, so, there’s that…)
I’ve been flying for a while, yet I only have @ 5,500 hours. That includes @ 3,300 multi-engine turbine hours (mostly as PIC).
Not a huge number, but they are in afterburning turbofans that I flew in really ‘interesting’ parts of the world.
I finally got my ATP at 55 years old; not because I wanted to be an airline pilot, but because I enjoyed the challenge of obtaining that credential…and I like being able to list it with my other FAA certifications when I sign my name.
IMHO the writer is all wet in his placing of blame.
There was a catastrophic failure, apparently of the oil cooler or lines leading to it,
which caused the loss of oil after start-up.
I doubt the oil weight, adding of MMO, or lack of a proper warm-up
had anything to do with it.
Sometimes it’s just a matter of “shit happens”.
There are plenty of aviation mishaps definitely traceable to pilot error,
if that’s what you wanted your article to be about.
There was no need to pick on this guy.
I think that the oil was definitely the wrong place to focus the blame. I personally never use oil additives and disagree with their use, but neither was an issue here. The puddle of oil at the hanger indicates a clear catastrophic failure on start up. Personally I believe strongly in warming up machinery and would never run up any piece of equipment without a warmup, whether it is the spindle on a machine tool or an engine. I would venture to guess that a thorough warmup might have disclosed an imminent failure. Still pilot error and give your head a shake, but don’t blame the oil.
I ferried a Bonanza from Texas in the Fall to Rhode Island with a stop in Kentucky for fuel where the temperatures were much colder than when I departed.. Upon reaching 10k’ cruising altitude I noticed my oil pressure reading was lower than normal, however still in the range. The local temperature in Rhode Island was in the 30’s and buyers inspection showed a lower than normal oil pressure. A call to a a local Tech at Pratt & Whitney who ask what weight oil (50wt) was in the engine he then suggested a change to 40wt oil the pressure would return it to normal. The oil cooler had been clogged by the heavier weight oil and colder temps contributing to the lower oil pressure reading.
The crank case vent could also have been blocked by ice at the beginning of the flight.
My Monday morning quarterback guess is that cold, thick oil along with high RPMs on start-up caused a spike in oil pressure which in turn found the weakest link, probably an oil pressure line or cooler and started a leak he wouldn’t have seen. He may have even had enough oil in the sump prior to takeoff to register pressure on the gauge, only soon to run out as the throttle was opened. There’s still a lot we weren’t told.
Interesting and timely article.
However, as Jorge ( below ) says we wouldn’t be reading it if the forced landing had been properly performed.
Too low on approach — problem. Too high —- no problem, since altitude/airspeed can always be reduced all the way to short final by a plethora of actions including side slipping, forward slipping, fishtailing, s-turning, flap ( if available. ), and, if feeling comfortable with control of the a/c, simply pitching up to where the stall warning starts !
Why not add gas to the oil? Standard operation in cold weather. It will boil off during flight.
Was a well-written article yet still…. to be noted…. that even a quick final run up sitting across the ramp from the owners hanger where the oil slick was apparent, even a couple minutes of run-up time allows for the eyes to glance left & right for a moment where a feller might notice said oil slick.
Maybe.
Power checks, always check T&P’s before takeoff.
As several others have said, all the hand wringing about the type of oil, use of MMO, lack of warm-up and the like had NOTHING to do with the accident. If there was a HUGE puddle of oil in front of the hangar and a trail leading to the runway, the failure started immediately upon engine start. If the oil pressure gauge had an indication in the green prior to takeoff, he would not have know about the pre-existing major oil leak. All in all, not a bad outcome for a complete engine failure at low altitude.
My IP in Air Force pilot training insisted I do a big picture viewing of the aircraft before I strap in and fire up the engine. I had to walk out front of the aircraft to make sure I had not forgotten anything, made sure all was symmetrical that needed to be symmetrical, ensure no runs, no drips, no errors, say a quick prayer, then strap in. I think if that pilot had taken the few seconds to do that out front of his hangar prior to engine start, he would have noticed the dripping or gushing oil had started.
Side note: I did find a bent gear on a T-37 after I became an instructor later at about the point when I has thinking, “what a stupid thing to be doing.” After noticing the bent gear, I have included it in my own instruction to students to this day. I have got missed items at times.
i would never take off or taxi anywhere with no oil preasure. That is a go no go decision!
Fact is. The failure happened at the hangar. The oil trail starting in front of the hangar is proof. Everything beyond that is inane drivel added to the report to obfuscate the matter. It wouldn’t have mattered if he had preheated the engine. Nor would it have mattered if he had warmed the engine thoroughly on the ground. The only difference would have been that his engine might have run out of oil before he got off the ground. Preheating and a long warmup won’t compensate for a failed oil cooler.
While the pilot’s lack of warmup and choice of oil may shorten the engine life, it won’t fail the oil cooler or create a catastrophic failure.
obfuscate is a big word.
Exactly. But be careful…logical contributions to internet forums are usually not tolerated😄
Well that’s 20 minutes of my life I won’t get back. The FAA always blames the pilot when they don’t have an explanation of what went wrong. Great essay about nothing, still why is there a puddle of oil at the hangar door??
I believe that the issue here was that he was high and instead of doing a 3)0 deg turn before attempting to land and forward slip if required all very close to the beginning of his perfectly chosen landing spot you would not have had to writ this article. This has happened to in various occasions when practicing power failure and always works great. Yet it is easy to be Monday morning quarterback and the most important thing here is nobody got hurt, according to my first instructor that is the definition of a good landing!!!!
Sounds like a lot of unfounded accusations and innuendo. As a 77 year old pilot, owner and mechanic I’m not
And I’m not seeing much relevant information, other than the brushed aside oil cooler. And I have used MMO for 60 years on and for different applications, including aviation. That is a trust thing since you can’t accurately repeat a with/without evaluation on the same example.
Also, without knowing the oil pressure 50 weight in this particular engine’s wear may have resulted in pressure no different than 30 in a less worn engine, again having nothing to do with the problem.
So the hose came off the cooler. Yup don’t hate the fan pusher. Love thy engin should be in the prayers list, check list. flying y’all brings you closer to God. either literally or just physically. Safe is fast and high. Slow prep is the new fast…