Engine about to die, minutes of power left, what to do?

[Direct C51]

Engines with splash lubrication and two strokes run without oil pressure for their entire working lives. As long as an oil film remains, the engine should survive, especially our pushrod aero engines. OHC engines that lose oil pressure almost always fail the cam bearings, the bottom end remains intact.

The entire reason our engines have pressurized oil is to lubricate the crank bearings and cam gear. The crank is partially submerged in oil and splash lubricates the non-pressure lubricated areas such as the pistons. The pressurized oil creates a barrier between the crank journal and the bearing so that they don't touch. Once you lose oil pressure, then this barrier is lost, and the bearing will quickly heat up, wear, and eventually fail. The time of failure will be based mostly on how much heat is developed.

If we lose oil pressure because of the oil pump, and not because of a loss of oil quantity, the splash lubrication will continue to lubricate the pistons, etc. This however will not be adequate lubrication for the bearings and the engine is still going to fail.

 

[Tantalum]

Instead, he pointed it at a field and landed with very little damage to the plane.

Good example of why you can't always follow strict rules, it really does come down to good ADM

 

[bflynn]

Just thinking of my lil bird, I cruise around 110mph Best Glide around 70, climb at 70 is probably around 700fmp, so would giving up 40mph be worth it? Losing 3/4 of a mile of distance every minute to gain 700 feet? I guess the math would be about glide ratio and how much glide that 700 ft gives me???

Assume a glide ratio of just 7:1, the 700' gives you 4900' of range, so more than 3/4 of a mile. If you have a less draggy airplane or one with a better climb rate, then it gets even better.

I suspect that this will change with altitude because as you go higher, both your climb rate and glide ratio are going to change because of the thinner air, right? So what's the formula for the crossover point?

No one mentioned the option of pulling the power back a little and doing a lower power best glide to extend range. That would reduce heat generation as well as provide better cooling, so maybe the engine lasts longer. Would be interesting to see what the glide ratio is in this configuration at different altitudes.

 

[Direct C51]

L/D and Glide ratio do not change with altitude.

 

[timwinters]

You do have survival equipment aboard, right?

Yes! This is my typical flight attire and gear:



Har!

Seriously, unless you're flying over the ocean, in Alaska, in other very mountainous/rugged/remote regions, etc., then it's really silly. Do you carry survival gear every time you fire up your car?

There are many places in NW AR where I'd far rather lose an engine at 4000' agl than to run off the road. I'd have a lot better chance of surviving and being found because I have a few options when in the air...none in the car when the road is immediately adjacent to and above a 200' bluff and the guard rail is severely rotted.

Besides, as has been oft stated on many of these pilots' boards, if it's not on your body then it's not survival gear...it's camping equipment.

But all that's for another thread.

Edit: BTW, I believe there's an old thread (either here or over on Red) in which Levy gave detailed instructions on how to assemble a survival vest. Some viewed it as educational, I viewed it more as comedy, especially the photo(s) of him actually wearing it...reading that thread was kinda like watching an episode of Home Improvement. Now that I think about it, most threads on pilots' sites are!

 

[Lindberg]

If you re trimmed for best glide, you do not need to push. The airplane will seek the trimmed airspeed on its own. If you're holding a pitch angle to maintain that speed, then be prepared to relax the pull (or even push). But if you're trimmed, no need. Next time you're flying, try it at altitude. Trim for best glide with cruise power. Once it's stable (it'll be climbing), pull the throttle (don't forget carb heat if so equipped) and see what the plane does. It'll nose over to maintain best glide speed. You can do it hands off assuming your plane is stable in roll.

This is not the case in any plane I've tested it in. What do you fly where this works?

 

[Huckster79]

This is not the case in any plane I've tested it in. What do you fly where this works?

Was going to try it yesterday at altitude but was bouncing n banging all over, windy and gusty here... but was straight down runway and was supposed to stay that way... as I’m pretty cautious with gusty crosswinds being a new to TW... ended up just wanting to get where I was going n back... winds shifted to 45 degree crosswind coming into home-so kinda tested it as I came in... fought the gusts down was rounding out n a stiff gust turned me from straight a fair amount just feet off the ground- let the continental ponies run to go round n try it again- I had been trimmed for 70 on approach- took pretty stiff forward to keep that nose down once we were to take off power... I’d bet I wudda done a nasty full power stall close to ground if I didn’t have pushed hard...

So I’m a bit skeptical but will try it at altitude...

 

[flyingron]

Nope. A bunch of old wive's tails here. I can tell you my engine came apart in short order. It will not run indefinitely without oil. Eventually something will seize be it a bearing or whatever and things will go to hell quickly.
Furhter, I don't by the "moving the throttle" breaks things myth either.

 

[timwinters]

This is not the case in any plane I've tested it in. What do you fly where this works?

I only have experience with 172s, 182s and DA-40s. It works on all three.

 

[jsstevens]

This is not the case in any plane I've tested it in. What do you fly where this works?

C-172. This is assuming you’ve trimmed forbest glide and are not just holding a pitch attitude. What planes have you tried it in?

 

[midwestpa24]

Furhter, I don't by the "moving the throttle" breaks things myth either.

Neither do I. Assuming a loss of oil and/or oil pressure, moving the throttle isn't going to compound that problem. In a loss of oil pressure, I teach to reduce power to idle and treat as an engine failure. The engine is more likely to run longer at idle. If it stays running it can give you an emergency burst of power to clear an obstacle or maybe make that last half mile to a clearing if necessary.

The other key in a loss of oil pressure is monitor oil temp. If oil temp remains stable, the pressure loss may just be a gauge or other issue. Land at nearest suitable airport. If temp starts increasing, you've lost oil and you are landing now.

 

[Lindberg]

C-172. This is assuming you’ve trimmed forbest glide and are not just holding a pitch attitude. What planes have you tried it in?

J-3, Citabria, and C170. It's obvious in the Cub. Climb at about 60 and approach at about 60, but it's nine turns of the trim crank in between. The 170, I tested very carefully at several trim settings.

 

[jsstevens]

J-3, Citabria, and C170. It's obvious in the Cub. Climb at about 60 and approach at about 60, but it's nine turns of the trim crank in between. The 170, I tested very carefully at several trim settings.

I’ve no experience in a J-3 but I would expect a 170 to behave much like a 172. Hmmm. I’ll try it next time I’m boring holes in the sky. I guess prop wash would affect it some. I do know dropping the RPMs 200 gives a nice 500 fpm descent without touching anything else.

 

[Lindberg]

I’ve no experience in a J-3 but I would expect a 170 to behave much like a 172. Hmmm. I’ll try it next time I’m boring holes in the sky. I guess prop wash would affect it some. I do know dropping the RPMs 200 gives a nice 500 fpm descent without touching anything else.

Small power changes you might not notice much of a difference. Try trimming fur a certain speed at a middle power setting. Then go full throttle. Hold the airspeed manually with pitch to avoid any phugoid then when stable let go the yoke. Do the same at idle. Will be interested to see how different the 172 is.

 

[jsstevens]

Small power changes you might not notice much of a difference. Try trimming fur a certain speed at a middle power setting. Then go full throttle. Hold the airspeed manually with pitch to avoid any phugoid then when stable let go the yoke. Do the same at idle. Will be interested to see how different the 172 is.

I'll give this a try next time I go flying. Real world data is certainly not as much fun as arguing on the internet, but hey! it's an excuse to go fly!

And I know this is what the primary CFI taught me when getting my private. "Airplane will seek the airspeed its trimmed for." Which may not be true, although I haven't found too many "old CFI tales" in what I was taught-he had 9000 plus hours and 50+ years of experience.

 

[FormerHangie]

The entire reason our engines have pressurized oil is to lubricate the crank bearings and cam gear. The crank is partially submerged in oil and splash lubricates the non-pressure lubricated areas such as the pistons. The pressurized oil creates a barrier between the crank journal and the bearing so that they don't touch. Once you lose oil pressure, then this barrier is lost, and the bearing will quickly heat up, wear, and eventually fail. The time of failure will be based mostly on how much heat is developed.

If we lose oil pressure because of the oil pump, and not because of a loss of oil quantity, the splash lubrication will continue to lubricate the pistons, etc. This however will not be adequate lubrication for the bearings and the engine is still going to fail.

Nope. A bunch of old wive's tails here. I can tell you my engine came apart in short order. It will not run indefinitely without oil. Eventually something will seize be it a bearing or whatever and things will go to hell quickly.
Furhter, I don't by the "moving the throttle" breaks things myth either.

I don't recall anyone saying that an engine will run indefinitely without oil. I have seen auto engines run for many thousands of miles with low oil pressure. My mother's car ran for a week with almost no oil pressure after some dope told her it was OK to run the car with the oil pressure light illuminated. For that matter, I've seen engines run for a number of minutes after breaking a connecting rod.

Engines fail in a number of different ways. Low oil pressure does not mean that the engine failure is imminent, but in an airplane it does mean you should get on the ground ASAP. My experience is that lightly loaded engines will survive an amazing amount of abuse for a short time unless something catastrophic happened. If you can throttle back to a low percent of power, you may very well be able to fly to the nearest airport at 70 or 80 knots, but then again, you may not. In any case I think the best course of action should you see the oil pressure sinking is just that.

 

[flyingron]

I don't recall anyone saying that an engine will run indefinitely without oil. I have seen auto engines run for many thousands of miles with low oil pressure.

DMSPilot did: Can't remember where I read it, but the engine will run much longer before seizing with no oil pressure while flying at best glide. More than enough to offset the slower speed.

My mother's car ran for a week with almost no oil pressure after some dope told her it was OK to run the car with the oil pressure light illuminated.

The idiot light is a far cry from not having any oil pressure.

Low oil pressure does not mean that the engine failure is imminent,

"Low" is a far cry from no pressure.

I can tell you I had no more than about 60 seconds from the first indication of trouble until I lost it all in my case. On landing, oil was pouring out of the compromised case (so there was plenty in the engine) but it wasn't circulating. Due to NTSB incompetence and Continental Engines CORRUPTION, I doubt I'll ever find out what exactly happened.

 

[dmspilot]

DMSPilot did: Can't remember where I read it, but the engine will run much longer before seizing with no oil pressure while flying at best glide. More than enough to offset the slower speed.

I'm sorry I don't remember saying the engine would run indefinitely, funny you can even quote my post word for word yet still manage to put words in my mouth.

 

[Kenny Phillips]

DMSPilot did: Can't remember where I read it, but the engine will run much longer before seizing with no oil pressure while flying at best glide. More than enough to offset the slower speed.
... Due to NTSB incompetence and Continental Engines CORRUPTION, I doubt I'll ever find out what exactly happened.

Hopefully you're prepared to substantiate the second allegation.

 

[Tantalum]

Bonanza

 

[flyingron]

Hopefully you're prepared to substantiate the second allegation.

They gave an absolute implausible explanation for the failure that some oil cooler fitting was loose. No way. It is not the case that I flew this thing until I ran out of oil, the thing was throwing oil all over the place when it came apart in flight. Something bad disrupted the flow internal to the engine and caused a bearing or something to sieze. You can see that from what's left. Of course, Continental would say there's nothing wrong with the IO-550.

I'm ****ed at the NTSB as while an airline can be party to the investigation, the pilot can not. So we have Continental doing their own teardown without either a pilot or the NTSB represented.

Oh yeah, and then there's Continental's reneging on giving me a partial core credit.

Yeah, corrupt fits them.

Not the first time. They lied outright about known problems with the starter drive in the 550 as well.

 

[Matthew Rogers]

DMSPilot did:
Due to NTSB incompetence and Continental Engines CORRUPTION, I doubt I'll ever find out what exactly happened.

So the NTSB is FAKE NEWS now!?!

 

[timwinters]

So the NTSB is FAKE NEWS now!?!

Actually, I have first hand knowledge that they can be. I witnessed a crash about 15 years ago in Harrison, AR. The pilot, a very prominent local "businessman", was...well...very connected. John Arthur Hammerschmidt, board member and chairman of the NTSB from '85 to '03, was a home town boy and "friends" with the pilot...or an associate of...or however you want to describe it (not to be confused with his dad, John Paul Hammerschmidt, a long time and powerful congressman from Arkansas who got his boy the DC jobs I'm sure).

JA was no longer with the NTSB at the time of this crash but was heavily involved in the investigation (debriefed the inspectors every evening in the terminal building, etc.) and the resulting NTSB report on this crash had nothing to do with the reality of what I witnessed. Oh, and the pilot's family was allowed to remove a bunch of "personal items" from the plane before the investigation began or any "authority" inspected The contents of the plane. That caused a lot of whispering around town.

As, an aside, and I'm not insinuating that it is related at all...

Harrison, AR is not far from Huntsville, AR and "in the day" there were as many, or more, drugs run in/out of Huntsville as there was out of Mena. It's a very remotely located town and the airport is remotely located to the remotely located town. When I lived in Harrison I would frequent the Huntsville airport because they typically had the cheapest gas in the area. It was an amazingly nice airport with amazingly numerous and nice airplanes for a town of 2,500...no I didn't forget a zero.

 

[midwestpa24]

Actually, I have first hand knowledge that they can be. I witnessed a crash about 15 years ago in Harrison, AR. The pilot, a very prominent local "businessman", was...well...very connected. John Arthur Hammerschmidt, board member and chairman of the NTSB from '85 to '03, was a home town boy and "friends" with the pilot...or an associate of...or however you want to describe it (not to be confused with his dad, John Paul Hammerschmidt, a long time and powerful congressman from Arkansas who got his boy the DC jobs I'm sure).

JA was no longer with the NTSB at the time of this crash but was heavily involved in the investigation (debriefed the inspectors every evening in the terminal building, etc.) and the resulting NTSB report on this crash had nothing to do with the reality of what I witnessed. Oh, and the pilot's family was allowed to remove a bunch of "personal items" from the plane before the investigation began or any "authority" inspected The contents of the plane. That caused a lot of whispering around town.

As, an aside, and I'm not insinuating that it is related at all...

Harrison, AR is not far from Huntsville, AR and "in the day" there were as many, or more, drugs run in/out of Huntsville as there was out of Mena. It's a very remotely located town and the airport is remotely located to the remotely located town. When I lived in Harrison I would frequent the Huntsville airport because they typically had the cheapest gas in the area. It was an amazingly nice airport with amazingly numerous and nice airplanes for a town of 2,500...no I didn't forget a zero.

I have seen the directions their investigations go as well. A friend of mine had a fatal crash that the NTSB blamed on W&B, despite eye witnesses reported a loud pop or crack sound shortly before the aircraft spiraled out of control from 1000+ feet.

 

[RyanShort1]

I have seen the directions their investigations go as well. A friend of mine had a fatal crash that the NTSB blamed on W&B, despite eye witnesses reported a loud pop or crack sound shortly before the aircraft spiraled out of control from 1000+ feet.

I know of stuff in Texas, too...

 

[Kenny Phillips]

They gave an absolute implausible explanation for the failure that some oil cooler fitting was loose. No way. It is not the case that I flew this thing until I ran out of oil, the thing was throwing oil all over the place when it came apart in flight. Something bad disrupted the flow internal to the engine and caused a bearing or something to sieze. You can see that from what's left. Of course, Continental would say there's nothing wrong with the IO-550.

I'm ****ed at the NTSB as while an airline can be party to the investigation, the pilot can not. So we have Continental doing their own teardown without either a pilot or the NTSB represented.

Oh yeah, and then there's Continental's reneging on giving me a partial core credit.

Yeah, corrupt fits them.

Not the first time. They lied outright about known problems with the starter drive in the 550 as well.

Who ended up with the engine bits? That should be evidence of some sort, and unless you were paid off by insurance, it's yours.

 

[Huckster79]

I think the term Fake News really means nothing anymore as it has too many definitions...

I think at the end of the day we all have to use critical thinking skills with everything we see and hear... from local/conservative/liberal media to politicians to NTSB finding to even our POHs with some things being lawyerly CYA stuff not real world useful info, etc. likely nothing is 100% factual and very few, but enough to be concerned to watch for, are 100% false.

I think it’s odd bedfellows to allow companies to investigate for problems with their own “stuff” at same time we can’t wrote off every NTSB finding because some are skewed through “politics” (not political party type- but the know someone who knows someone type) and some are tainted by a company that gets to investigate their own stuff...

 

[flyingron]

Who ended up with the engine bits? That should be evidence of some sort, and unless you were paid off by insurance, it's yours.

I have them (well, my mechanic does).

The NTSB hasn't issued a finding. The Continental report is bullpoop and even the NTSB realizes that.

 

[Lachlan]

Was going to try it yesterday at altitude but was bouncing n banging all over, windy and gusty here... but was straight down runway and was supposed to stay that way... as I’m pretty cautious with gusty crosswinds being a new to TW... ended up just wanting to get where I was going n back... winds shifted to 45 degree crosswind coming into home-so kinda tested it as I came in... fought the gusts down was rounding out n a stiff gust turned me from straight a fair amount just feet off the ground- let the continental ponies run to go round n try it again- I had been trimmed for 70 on approach- took pretty stiff forward to keep that nose down once we were to take off power... I’d bet I wudda done a nasty full power stall close to ground if I didn’t have pushed hard...

So I’m a bit skeptical but will try it at altitude...

They gave an absolute implausible explanation for the failure that some oil cooler fitting was loose. No way. It is not the case that I flew this thing until I ran out of oil, the thing was throwing oil all over the place when it came apart in flight. Something bad disrupted the flow internal to the engine and caused a bearing or something to sieze. You can see that from what's left. Of course, Continental would say there's nothing wrong with the IO-550.

I'm ****ed at the NTSB as while an airline can be party to the investigation, the pilot can not. So we have Continental doing their own teardown without either a pilot or the NTSB represented.

Oh yeah, and then there's Continental's reneging on giving me a partial core credit.

Yeah, corrupt fits them.

Not the first time. They lied outright about known problems with the starter drive in the 550 as well.

Spill a quart, wipe up a gallon. Spilled stuff always looks much bigger than contained liquids.

 

[flyingron]

There was plenty of oil pouring out. I didn't get any sign of oil leak before the thing came apart. Then I had oil coming to the windscreen.

 

[LongRoadBob]

Good example of why you can't always follow strict rules, it really does come down to good ADM

This is a really interesting thread. I'm getting the idea though that "THE answer" is only mostly knowable AFTER the fact when you find out if the engine could last a lot longer at idle, or if the engine actually quit, or was just threatening and what was possible at the time...which has now passed.

Maybe I'm just not grasping it all, but it feels a little like bird strike avoidance. A thread here on that where some felt it was better to descend, some though climb was better, some had more thought in it and meant that certain types of birds will tend to avoid you by descending where others by diving. For most of us, pick one and just do it (or stay in current attitude and hope the bird avoids you). Seems a little like rock, pape, scissors.

Maybe experience, feel, and intuition (with a base of knowledge of the systems) have a lot to say too.

you have to take into account oil pressure, temp, sound of the engine, history of the engine, your experince if any of them, if it seems it is going to quit soon, or may be able to last. And Climb or not.

My impression is if it is a wash on the variables, sounds like keeping altitude is better than climbing unless some other variable in the situation tells you it is likely to give a benefit. Mainly because of it being harder on the engine.

These are just what I'm grasping of the points I read here.

 

[flyingcheesehead]

My impression is if it is a wash on the variables, sounds like keeping altitude is better than climbing unless some other variable in the situation tells you it is likely to give a benefit. Mainly because of it being harder on the engine.

I would disagree - If you don't change the power setting, climbing isn't any harder on the engine, and you'll lose less energy to drag climbing than you would in maintaining full forward speed.

Math and testing yet to come.