Two Oil Temp Runaway Emergencies!? Engine Data Debrief Debunks Myths 

1. As a prior Air Force pilot, I love a good data driven debrief. This is fantastic. 2. I think there may have been some terminology confusion in a lot of comments from your last video with the false indication. A common term in US military aviation (maybe civilian too?) is "the field", but that means "the airfield". Maybe in Canada that's not a common term. A lot of criticisms from the last video were about leaving glideback of "the field" were in reference to a moment where is sounded like you were leaving glideback of a closer "field" (airfield) for you home field. I was one of those criticisms and definitely agree that electing to try and push to a strip of asphalt is far better than landing in an actual field (full of corn, not smooth asphalt). I know it's hard when you are trying to tell us a story, and none of us were there. Apologies for the Monday morning quarterback. 3. I love and respect Jason, but I've got to disagree with him here. Avoiding declaring an emergency for fear of having to answer questions is absolutely the wrong mindset. Be spring loaded to say "callsign, emergency, type of emergency (impending engine failure in this case), souls on board, what you are need from ATC (proceeding to final rwy 30R)". If they want more info than you have, be a pilot in command and tell them to standby. That should be a clear script in your mind before you take your private pilot check ride. Any scenario that is listed in your emergency procedures section of your checklist IS AN EMERGENCY and most likely warrants an emergency call. 4. Dave's handling of his emergency was fun to watch. I think he handled it extremely proficiently and it was great to hear him talk himself through it. He started going down mental rabbit holes and then reminded himself to get back on track saying, "work the problem". Love it. 5. I've seen a few oil emergencies myself, all in turbines though. One was a high-pressure oil line that was cracked and spraying oil into the intake plenum. The only indication in flight was a very slow and steady decrease in oil level, but within normal operating parameters. I knew the aircraft well enough to notice being out of the ordinary though before the yellow caution came on. I was essentially over the field, and in a slightly rushed decision, I decided I wanted to get the aircraft on the ground sooner rather than later. I notified ATC and started an aggressive slip and that's when all hell broke loose. I had only dropped about 10-12% oil in the previous 25 minutes of flight, but once I started the slip, I lost about 40% more of my oil in mere seconds. I immediately came out of the slip and declared an emergency before flighting the rest of my descent over the field in a spiraling engine out pattern. Landed with about 35% oil. Going back through the data, I came to similar conclusions. Low oil level didn't really change the oil pressure that much. It dipped in those few seconds of slipping/pissing oil, but once I straightened out it went mostly back to normal. EGT was normal for the power settings as well. Oil emergencies are so much more varied and nuanced than almost any checklist I've ever read says they are. 6. Thanks for the great debrief. Pilots are the worst when it comes to "what I would have done is...". It's a vulnerable thing to put your flights, let alone your emergencies and mistakes on the internet for all to see. Good work.

From a controller's perspective -- if you have an emergency PLEASE declare it as soon as possible in order to get the best possible handling. "Pan-pan" or "mayday" just indicates different degrees of emergencies. And, if any controller gets too talkative, PLEASE tell us to standby, to shut up, or just ignore us if you need to. PIC authority includes authority over communications.

That air duct flange needs a ridge to prevent such episodes of the scat sliding off. I am adding that to mine. Thanks for your videos.

Exactly the same thing happened to me while flying my C172 over the Río de la Plata on my way to Isla Martín García in Argentina: I just passed San Fernando airport and abt 10 miles over the water the oil temperature jumped to the top of the instrument (analog)... 180 turn and direct to San Fernando... Did not declare an emergency nor PAN, just said to the tower that I had an abnormal oil temp indication and had to land there, the controller cleared me and asked souls on board fuel remaining and if I needed ground services upon arrival. Less than 10 minutes later I was safe on the ground. CHT and EGT stayed in the green all the time, it was the lose hose to the cooler that had to be replaced as it collapsed beyond repair. Thanks for sharing the video, now I have a better picture on what happened to the engine while I was strugling to land as soon as I can. Good winds to all & keep it up, great channel!!

Regarding the debunking of a myth, I always was told that lower pressure should translate to watching for higher temps. However, not the reverse. The pressure will move first. If the temp moves up, something else may be amiss, but doesn't necessarily mean pressure will drop. Maybe I am wrong, but it held true in your case. My fist thought was the failure of items that are meant to cool the oil. Like the Vernatherm or a hose. Regardless, the response of getting the plane on the ground ASAP is the absolute right move. Really nice job of reacting, while staying calm and in control and flying the plane to a perfect landing.

Nice job on breaking down both situations using recorded data which gives a great perspective of both situations. We are so lucky to have the ability to record this data.

Declared a emergency just last week in a trainer. Was coming into a Barvo shelf with engine failure imminent. I needed to stay high "to save myself" and go into the bravo to assure I could make it to the closest airport in the event I lost the engine completely. Weirdly upon landing, I wasnt given one question which was odd to me. Even tried calling the Approach center to follow up but still no questions. Completed a Nasa form just incase. Its always been my thought process to declare the emergency in the event that my life could be at risk.

Best part of this video was the last 10 seconds! Definitely electric for oil emergencies, none of the acoustic nonsense.

i had an in flight electrical fire...smoke and burning smell ! training kicked in....turned off master, flew to nearest airport... aprox 5 miles, no radios of course ... landed and got out...phew. (short in modified old standby radio) Cherokee 140.

Jon McCormick is the best - so glad to see you went to him.

1:30 That little yellow bird really hauls the mail! No name yet? Glad everything turned out okay.

So one thing I would like to add, if I may, that we employ flying the jet is having an SOP for when a thing such a RED CAS happens. We use FORDEC in our company, but it doesn't have to be that. What this does (as does any SOP) it keeps your mind focused on working the issue (like Dave said during his emergency) in an efficient and coordinated way. Maybe consider adding this to your arsenal of your pilot's toolbox? Another thing I wanted to mention is, maybe having a written emergency or abnormal quick reference checklist in the aircraft that you can pull out to work the issue would be a good idea too? That way, especially if you're two pilots on board, one can keep flying the aircraft and the other one can pull out the checklist and start that procedure of "working the issue" (worksplit procedure). And even if you're by yourself you can make sure you don't forget anything.

So much good info in this video! Makes us all better pilots if we are open to these discussions and "thought experiments". Someone once told me that if an indication or problem on the ground would prevent you from going flying, it would be an emergency in the air. So, if I did a runup and saw 250 deg oil temps..I'm definitely not going flying, and I'll definitely be treating it like an emergency in the air!

Perfect song for problems with the oil: "Under Pressure" by Queen

That’s a slick, good looking airplane. The red one is OK too!

Going to click the link and subscribe to Pilot Nerds as soon as I'm finished writing this. Great data analyses, and also glad neither of you were distracted by over-analyzing during the emergencies. I need to learn how to disseminate and display the G3X data logs as you guys have; just haven't gotten to it yet. Glad Jason Miller chimed in with that great point of ATC distraction after declaring an emergency. Lesson One: FLY THE AIRPLANE. All else comes second. On a side note: in the background I spotted Jason's rebuilt RV-8 in the paint shop at the same time; that was pretty cool. Great ending tags!

This is real good stuff. Thanks. Ya you could have made a pan call, maybe should have but its not really required unless there is other traffic in the way.

Good advice from Jason Miller at 19:30, (some pilots are not very good at multitasking).

You had mentioned about wheel pants and fields making you flip over. I had an engine out in my Rv9 tail dragger around 2006. My friend wanted to feel weightlessness. Well the float in the carb got stuck. At the time I went full rich, boost pump on, switched tanks and soon did the Mayday call when I exhausted all options to get it going again. So boost pump on was the worst thing as I was just filling the AirBox with fuel. That could have started a huge fire, but engine quit, first thing is mixture, boost pump and tank switch. You Never really know why the engine quit so you try everything. I did all my relay calls with a KLM airlines captain. Big item was getting the position report right. I picked a field, got everything set up and shut down all the power telling the KLM captain I would be back with him once on the ground. The ground roll was fine even with the wheel pants on in a recently cut field as it was dry. Soon after my plane was surrounded by Black Angus Beef! The RCMP showed up from my mayday call. I had the cowling off by then and found the problem. Started it up and all was fine. My friend jump in the RCMP car, and they put all the lights on and siren to move the cows away so I could take off. It was a time with no camera phones but the memory of the RCMP herding cattle for me was pretty funny.

As an engine geek, that is one of the best and strongest sounding 4 bangers I think I've ever heard!! I also see a Mesa Boogie amp and some pretty sweet looking guitars in Dave's space! We would get along great, I've been a guitar player and collector/Luther for 50 years! Oh, and it was a great video too!! 8) LOL --gary

Ok I’m ready for the fun ✈️. Hit the switch, let’s go!

As a pilot the Pan Pan call and Mayday calls are both tools to solve problems that were not present on these flights. Those tools WILL get me to pavement sooner, clear impediments, change my place in line, and engage emergency services…for instance. None of those things were necessary for the safe conclusion of these flights. Makes perfect sense to me that those tools were not utilized. Great video. Thank you!

Awsome debrief👍

Great to see this one. I was pondering it all after the vids on the actual oil difficulties. My own RV14 journey took two steps forward recently, looks like I'll be starting in June. But....if the current economic crises continue, then it'll be three steps back. We'll see...

Very good info

Why would you get grief for trying to save the engine? It's literally what the USAF has us do to the maximum extent possible.

Oil pressure emergencies absolutely call for a Blues Song! 😁

As Steve knows, I haven't flown as PIC since the early 1980s. I thought that Pan-Pan was the European equivalent to Mayday. That's not true, Pan Pan is used throughout the world, including the U.S. To whether or not Steve should have called a Pan Pan, I'm going to agree with Jason. The engine, while having had a high temp warning, was running smoothly and producing power, and he must have had enough altitude to make it back to Windsor, since he did. I don't see a reason for the call. Now, had the engine started running rough, I would have declared an Emergency, there's not question about that. I'd rather answer the questions and be alive than not declare it and have to have someone go searching for the ELT signal. Steve, great follow up video. I'll also be checking out Pilot Nerds.

I haven't seen another Chinese Crested in forever! However the planes are nice too lol

That keyboard perfectly illustrates the joys of a daughter Steve 🤣

Thank you for this. I commented in the last video that there has to be a way to restrict the tube from coming free. Is this a situation where a raised bead formed into the aluminum tube is warranted?

I'm afraid I entirely have to disagree with withholding information about an emergency declaration. You can tell who has worked in a structured system with procedures developed from many failures.

Really glad my RV7A has the oil cooler mounted above #4! I would bolt the cooler tube to the air ducts you got way too much riding on a $5 hose clamps!

Hi Steve and Dave, That was a great video to show. I hope Dave is doing ok, he looked a little thin... I really liked the un-painted version but the yellow really looks great. Thank you for sharing such a great topic. We all will be able to store that into our memory chip. It's great to learn something new everyday in life. Take care, Be safe.

There’s likely a pressure regulator that would stabilize the pressure over changes in temperature and rpm. No surprise.

I would have thought the CHTs might have increased from the 5inch hole in your baffles, not from the elevated oil temps. I imagine with the Scat tubing connected, the oil cooler provides some back pressure, keeping some Delta P from the area above vs below the cylinders. Blowing off the scat tube would let the delta P equalize. I wonder if he didn’t pull the power off right away, perhaps you might have noticed something?

Do you have any advice for those of us worried about this scat tube coming off? I have mounted mine and it was not super simple with the shape of the oil cooler inlet and the top portion is actually the one that comes off. Was your clamp grabbing the wire? Was it not tight enough? Has it come off since?

Real interested to hear what engine maintenance resulted from the over temp. Obviously the heads are fine. Bearings probably good I’d think. Oil change and analysis? Another change after 5 hours and analyze again?

Steve, I am curious what the fix was for the cooler air tube… Is it sliding off ? Did you forget to tighten the clamp?? Those things a slippery on painted and non ridged surfaces.

The obsession in GA with the mayday/pan pan call seems to be a very common issue. If you are getting everything you need from ATC then that radio call is just a formality that is nice to do if able but requires higher workload as a result. Aviate, navigate, THEN communicate - a concept often lost in the GA world.

Why is the metal tube the ducting goes over smooth? Shouldn't it have flare/knurl or something to stop the hose clamp and ducting just sliding off?

This is so good that you show this. I would love to see other people reacting to problems like this in front of a camera. Let the keyboard warriors do their thing and you keep doing the informative stuff! :P

Why wouldn't you bead the tube the duct slides onto after the first time this happened? Its standard practice in the automotive world with pressurized tubing and ducting. Also not sure if you're using constant tension clamps, but I would think the combination of the two would fix this problem long term.

What! No song ! Songs, especially rhyming songs, are a great way of committing things to memory. A snappy 30 second tune about the perils of over temping engine oil and diagnosing faults by making correlations with data that may actually have minimal, or no correlation whatsoever with the original fault, could save countless lives. Maybe.

Surely there is and oil pressure relieve valve, the job of which is regulate the oil pressure? So, the only time you would have low oil pressure is at low RPM or if the oil has got too thin which it should not unless it has gone out of grade due to age or if it has got way to hot.

Ex-ATC here, and a private pilot of 30+ years... regarding, should you declare an emergency, or Mayday, or PAN PAN ?.... or not? Just tell ATC in plain English what you are dealing with. Plain English, and they will help you by giving you priority, expedited handling, etc. Something like this; "Hey ATC, we have a run away oil temperature, engine failure is imminent, we need to get on the ground IMMEDIATELY. I want straight in to runway 26 (or whatever you want)" and that's it. You tell them what you want, and do it. You're number 1. And if they ask any questions and you are busy, the word "stand by" should be the only thing you say unless you have the time to humour ATC questions.

19:18 Just because air traffic asks a bunch of questions, does not mean you have to answer them; you know, the whole aviate, navigate, communicate thing. EDIT: I just saw that dozens of other people have already said the same thing. I should look before I type.

You can create a simple sensor for the duct using a magnetic door/window sensor usually used for alarm systems. The flexible duct end and cowling could each have half of the sensor and if they separate, a light or alert could be displayed on the panel. These sensors are only a couple dollars each and are extremely reliable. It would alert before leaving the ground, or if in the air, as soon as it separates.

On the call an emergency issue, and to be totally clear I am not a pilot. The purpose of the call is to give you priority Access to getting back on the ground and whatever resources you need to do that. in the first emergency you were directly over the airport you seemed to be the only one in the air around that airport and you had people on the ground watching you. There is no local Tower controller it's a completely uncontrolled VFR Airport. You already had everything that you needed to get safely on the ground. In the second emergency flight Chops was handling aviate and navigate. The other guy was handling communicate If you're going to yell at somebody for not calling a PAN that's the person that needs to get the recommendation not the person making sure that the plane is being handled correctly. I will say that most people are in denial when they're having their emergency. They are reluctant to call because every other area of their life has trained them to deny there is a problem. It is not a general aviation issue, it is a societal issue.

Can I make a suggestion on you oil cooler duct? Vena HTD ducting, same as Sceet, double wall, lasts longer and has a firmer attachment.

It's impressive how resistant modern multigrade oils are to high temperatures. I'd think the engine thermostat would also open further to cool the cylinder head and offset some of the oil heat.

The conversation about "should it be a mayday or pan-pan call" is sort of silly. As long as you say *something* that results in ATC and other aircraft clearing a path to meet your situation's demands, and conveys the seriousness of your situation, you have met the threshold of what to say. I would only say "mayday" if I wasn't already in contact with this controller or CTAF, and "pan-pan" is unnecessary because it isn't at the level of emergency, so you just explain your situation to ATC. Honestly, any request that prioritizes you over another aircraft is just an emergency, so... either mayday or nothing. The word "emergency" is just as good as "mayday."

Interesting. I'm glad that I haven't had a real emergency yet, only one carb ice scare, but caught in time. The oil temperature/pressure correlation is true at low oil temperatures. With cold oil during a cold start on a cold day, oil pressure, especially with a single-grade oil, can go up pretty high even at low rpm, but will go down quickly as the oil warms up. But at the higher end I've never thought that. Oil pressure limiting factor should be the pressure relive valve, because at higher rpm the oil pump will create much more pressure than is required. Same for CHT; there isn't really that much oil in the combustion chamber for oil temperature to make much of a difference.

This is all great stuff, but someone educate me, I'm not a pilot. On any auto application it is imperative to have a lip on any tube that holds a hose, especially in a pressure application. That is the basic engineering premise of a hose clamp, once tightened it cannot fit back over the pipe if it has a lip that is a larger diameter. Seems to me an absolute misunderstanding of mechanical principles on something that can kill you very quickly.

Can’t disagree with any of these conclusions, but I still think Garmins EMS should be able to identify fault conditions like this. A change in sensor resistance faster than the thing can change temperature due to its mass, and/or noisy sensor readings should be flagged as a likely sensor fault giving the pilot more information about the problem. What if this were a trim position sensor? You’d expect the software to flag when the sensor readings are erratic and don’t correspond to the expected control surface movement. Very easy to do in software.

In a scenario like that, being over an uncontrolled airport already with a still functioning engine, what would actually be the benefit of declaring a pan? Since a lot of people are saying you must always no matter what. I understand if you were much further away it would benefit for sar purposes or if he ended up in a field they would know sooner, but I wonder why it's so important to do so in the last very busy 2 mins of a flight. I'd just like to understand how atc would have been able to benefit the situation at the time?

Super interesting. I've noticed that a lot of Pilots are guitar players.

link to the nerdy channel?

Just a Question, would a Secondary oil temp gauge worked well i this case…

I wonder what's causing that hose to keep popping off probably need some kind of stronger hose clamp

2 lbs per qt guys when was the last time you did a w&b?? lmao

Sounds like a trip to Mike Patey to have him design a carbon fibre cooler duct is in order!

A mineral oil as apposed to a syn multi grade MAY have different affect in this situation. Just a mechanics two cents

Interesting that the scenarios you missed in discussion were the only scenarios I’ve ever heard regarding oil pressure and temperature (never heard of either of your myths presented before - and I’m not surprised at your results because they are positive displacement scavenge pumps so the logic makes no sense that you’d lose pressure with higher temps). A long term increase an oil temp coupled with a long term decrease in oil pressure in cruise should flag you to consider a slow oil leak. Obviously your emergency didn’t handle this data but your discussion didn’t address it either. I can say from working with race engines this is a condition I have witnessed. The other condition was the opposite of a sudden drop in oil pressure which you said there is a myth temp would go up, this wouldn’t happen, it would be supplemented by a drop in temperature (yes a drop) should lead you to believe you just had a catastrophic loss of oil. Why you may ask? Because loss of oil would mean you aren’t taking heated oil across the sensor anymore. I have not seen the latter condition with oil but have experienced it blowing coolant lines before.

To add “data” points for accurate diagnosis of imminent engine issues or oil cooler failure, Im going to GUESS the oil temp sensor is after cooler, before it goes through the engine loop back to the cooler (or not). Adding a sensor just before cooler on cooler entry - would tell you the delta in oil temp and if the cooler is working or the source of issue. Normal operation will show whatever delta you have - call it 10 or 20 deg….and if a cooler blower hose blows off entry and outlet temp would be about the same, and at varied levels of issue of cooler (plugged, blocked internally, air failure, partial air failure etc). The before cooler temp will be a better indication of engine issues as well, as a sudden quick rise in oil temp pre cooler would be a sure sign something has changed….

Déjà vu

do I really have to prove overall engine temp - which IS reflected in cht, is correlated to oil temp!!!?? What creates oil temperature? apparently king Canadian (as a canadian) here hasnt considered that. If you kept flying - with the oil cooler broken, what temp would the oil peak at? why would it peak at this temp? what does cooling the oil accomplish? If we altered the oil cooler size, air flow over cooler, and qty of oil pumped, could we alter peak oil temps? what oil temp is desireable, and why? Why does oil temperature take a long time to come up, almost as if oil temp tracks with engine temp?? hmmmm yes - large heavy chunk of alum has large thermal inertial - aka time to get heated up or cooled down. small volume of oil has lower thermal inertia - faster to respond. But everything wishes to equalize - oil and engine. and the oil is cooled to help cool the engine. In the case of this engine, it must be cooled because the gap between usable safe oil temp vs engine temp is a large gap. if the engine naturally ran around 230f - ud never have oil temp run away issues UNLESS you have engine failures with internal frictions. I commented last time - and will again - maybe someone should find the true usable end of the oil before oil break down. Its our experience in national championship winning engines - that its well over 300f for short periods.

Not a Pilot or AP ... but please read. I am a Master Mechanic with a degree in Automotive and Diesel Technology with Factory training from FoMoCo, Daimler Chrysler, and GM/Delphi as well as certifications from many aftermarket manufacturers. Over thirty years of work experience. While I agree with you on the greater majority of your data-backed commentary, I would like for you to appreciate the fact that 90 seconds of data *does not* give you the long term data to support your theory of cyl head temp not being affected significantly by oil temp. Without a perfect understanding of the airflow within the engine compartment I would like to share some opinions. I am assuming from the video at 0:45 the engine is cooled by ram air/ prop air that is forced directly over the cylinders and heads then is ducted to the oil cooler (when you hook it up) before it is dumped outside. The duct not being secured is the clear reason for the rapid rise in oil temp. The high engine speed was a secondary and significant cause which was immediately reduced once the temp warning was detected (now audible, good call there). Reducing load/RPM instantly reduced production of heat on the engine and oil which did not show up in the 90 seconds of data because as you mentioned there is a lot of mass and it takes time for said mass to go from rising heat to lowering heat. There was only a minor linear change in cyl head temp during the rapid increase in oil temp because the engine itself still had *almost* normal airflow over the cylinders/heads, whereas the oil cooler had a massive reduction of airflow. Now let's change the circumstances of the event. You are no longer over the airfield on a test flight, you are over some huge body of water or, God forbid, climbing a mountain range. Landing is not an option for at least 30 minutes. This changes everything, and if you still believe your engine temps will not catch up to your oil temp, I believe it will unless you take immediate action to minimize load and RPM. Going rich will help a lot! Get to cooler air if you can. If you have no choice but to carry on and even require high power settings, you will see the engine temp start to rise sharply to match the oil temp. The oil *IS* used to cool the engine. Oil is squirted on the bottom of the pistons and is constantly being applied to the cylinders and scraped off by the rings. Data at the ten-minute mark will tell you what the likelihood of you making the next airport will be. Ignoring the oil temp and assuming the engine temp will stay linear is not a good plan. All the air cooling the cylinders is slowly baking everything in the engine compartment and looking for a place to escape. If the loose duct compresses closed this heating will be amplified since air in must have a place to go out and if it doesn't that side of the engine no longer has enough airflow to cool the cylinders and it's going to get ugly pretty damn quick. You get my point. PLEASE RESPECT THE AIRFLOW...AIR IS FOR MORE THAN JUST LIFT MY FRIENDS. Double check those ducts! And fly safely!

I think these videos would be more clear if you would first show whole footage and then do the debrief. Now the scene is hopping around a lot!

Rumor has it he died in the Dallas air show?? Can anyone confirm?

Hey I have a question, why so many pilots use imperial units, including you, when it was internationally agreed that all units used in aerospace need to be in metric? Even NASA is using metric.

I deleted my comment about the B-17 in Dallas so as to not spread a possible rumor.

You frequently have disclaimers about not being a CFI and are not giving instruction, where was the disclaimer that you guys aren’t mechanics and you may not know what you are taking about? I feel like having an actual A&P on this kind of discussion would have been more valuable then several non-experts speculating about how and why things behaved as they did. Mike Busch would have a field day with this kind of data and would be a great person to discuss it with.

Mr Miller seems to be getting more wrong than right recently. His interview with Mr Gryder about himself and Mr Haase cutting off traffic on final was eye opening. Definitely a "holier than thou" attitude towards aviation, which other aviators would be correct to avoid. Insofar as declaring an emergency goes, practice making the controller wait. They're your last priority. If I recall correctly, Mr Gryder had you yourself practice that exact thing, Mr Thorne, by doing math before responding to an ATC call. So declare the emergency, let them find you on radar, tag you up, and start moving traffic out of your way. You have 0 responsibility to them at all. Ignore them if necessary. Hesitating to declare is monumentally stupid and downright dangerous advice.

19:30 bad, bad, advice. ALWAYS DECLARE MAYDAY OR PAN-PAN-PAN, if they have questions you can't fit into your workload, say "unable". But any advice to be hesitant about declaring an emergency or to deal with it on your owns just wrong. Please don't spread this kind of misinformation.