When do engines fail on takeoff?

[INA201]

I always try to reduce or increase power in any situation very smooth and slowly. I’ve flown with pilots who make quick power adjustments and some who make smooth slow power transitions.  My first flight instructor who had some 26,000+ hours would jam the power in on touch and goes in the 172. In her career she has had one engine failure due to an improperly installed helicoil for one of the spark plugs.  Personally, without imperial data, we should adjust power smoothly if at all on takeoff. The crankshaft, cams, cylinders, prop, and all other moving parts have a ton of inertia that is affected highly with adjustments of power.

 I like to get everything up to operating temperature as well before takeoff.   Having an engine that is cold being asked to pull my 2740 pound aircraft up into the sky is putting a lot of strain as those parts warm up and are pounded on. I don’t know the stats on this but just seems to make sense to me.

Also, MX, engine monitor, and if something just “ain’t right,” don’t go. 

[jaylw314]

7 hours ago, mike_elliott said:

While I do not have any empirical data to share to validate this other than observations, race car engines typically let go at power reductions. Granted, these are highly stressed vs our ol tractor motors. Have I mentioned air cooled internal combustion engines are the work of the devil?

What I preach (teach) is keep those money knobs all forward until after the kill zone at Vy. Kill zone = <800' AGL Then I suggest keep them all forward except mixture (for NA engines) until cruise altitude (exception 231 and other turbos...for example, Ill reduce the Bravo to 34 mp for cruise climb) Your POH is a friend here

Even if power reduction has nothing to do with the risk of engine failure, it seems like leaving the knobs alone until you are at altitude would be safer for other reasons, like avoid distractions and errors.

Once when transitioning from climb to cruise, I reduced throttle, then reached to reduce RPM.  I grabbed the knob and pressed the button so I could pull back to a low RPM setting.  It took me a moment to realize I had grabbed the mixture knob, and in that moment I hit some turbulence, throwing me back in my seat, which had the effect of yanking the mixture knob.  Fortunately, it didn't come all the way back to ICO, but it sure freaked out my passenger, who happened to be doing my instrument checkride   I explained what happened and why, and she seemed satisfied and somehow passed me.

That's the sort of mistake I wouldn't want to make below 800' AGL.

[MBDiagMan]

I am not an aircraft engine expert, but I have lots of automotive piston engine knowledge.  In an engine that is driven hard, the connecting rod deals with tremendous stresses.  It is compressed and then tensioned rapidly, a tough life for a steel member.  Rods typically break under one or both of the following scenarios: the most common is loss of oil for obvious reasons, then second most common is at high rpm on the intake stroke at high RPM while pulling hard against a vacuum.  This is why an engine designed for low RPM, low performance doesn’t last long if driven by a wild teenager, or anyone who constantly over revs.

From that second scenario, one thing that might be coming into play with the retarding throttle situation, could be that the closing of the throttle creates a vacuum that the rods must pull against.  Although these engines are designed with strong components and adequate breathing, it might be just the nudge that could make a tired connecting rod decide to give up.

Just a theory.

[jetdriven]

There are a lot of reasons to not chop the throttle at high air speeds or to have the prop driving the engine. 

[Piloto]

The interesting part is that engine failure on take off happens on piston and turbine engines. One common cause that I see is water displacement toward the fuel pickup during acceleration and climb. Airplane fuel tanks are big and prone to internal condensation or rain water leakage through the fuel caps. And when fuel is mixed with a small amount of water it can increase the power stroke significantly to exceed the connecting rod or cylinder wall stress tolerance. And when the airplane crash and burn no one is going to find any water traces except those of the fire trucks.

Another factor that can damage and engine on takeoff is an intermittent spark plug, plug cable or magneto. If there is no ignition during a power stroke on the next power stroke there could be more fuel in the cylinder causing a greater explosion thus more stress and failure.

Reducing power after takeoff will not harm the engine but pulling on the mixture rather than the throttle could cause engine stall or damage. Normally your right hand is on the throttle during takeoff but when you move your hand to the gear switch or lever it may not return back to the throttle but to the mixture. Always visually check. On some older Mooneys the mixture or throttle control can creep back in-flight due to vibration. 

Before the takeoff run verify full RPM and MP. Not having enough power and heavy on weight may cause partial lift on ground effect but not enough to clear the trees.

Weight is a significant factor on takeoff. If the runway is less than 2,000ft do not fill more than 1/2 tank.

José

 

 

[gsxrpilot]

So went out to fly formation with Bucko today which I said would require plenty of power reductions at takeoff and all other times. Well, I had an engine failure. Fortunately I was still on the ground.

I'll put the details in another thread.

[Cyril Gibb]

7 hours ago, Piloto said:

One common cause that I see is water displacement toward the fuel pickup during acceleration and climb. Airplane fuel tanks are big and prone to internal condensation or rain water leakage through the fuel caps. And when fuel is mixed with a small amount of water it can increase the power stroke significantly to exceed the connecting rod or cylinder wall stress tolerance. And when the airplane crash and burn no one is going to find any water traces except those of the fire trucks.

Correct me if I'm wrong.  (as is often the case)

Early in this same thread you mentioned you had an engine issue with water contamination.  Later (this same thread) you advocated installing illegal sump drains which allows water buildup in our tanks that apparently based on your annual guidance you're willing to accumulate until annual time.

Now again, you're mentioning the danger of water accumulation.

I just ignored the sump drain suggestion, but am concerned about newbies that read that and don't realise the illegality, danger and insurance voidance of your recommendation.

Did I just misunderstand?

[Piloto]

8 minutes ago, Cyril Gibb said:

Correct me if I'm wrong.  (as is often the case)

Early in this same thread you mentioned you had an engine issue with water contamination.  Later (this same thread) you advocated installing illegal sump drains which allows water buildup in our tanks that apparently based on your annual guidance you're willing to accumulate until annual time.

Now again, you're mentioning the danger of water accumulation.

I just ignored the sump drain suggestion, but am concerned about newbies that read that and don't realise the illegality, danger and insurance voidance of your recommendation.

Did I just misunderstand?

The drain valve F391-72 is used in all the Cessna piston planes with no issues. The F391-72 is used in the Mooney long range tanks, with no water  accumulation issues. I use the F391-72 in the mains for the same reason. The safety of my family is first over others design criteria. I just disclose my findings but is up to each owner to do whatever they feel more comfortable.

José

[jetdriven]

9 hours ago, Piloto said:

The interesting part is that engine failure on take off happens on piston and turbine engines. One common cause that I see is water displacement toward the fuel pickup during acceleration and climb. Airplane fuel tanks are big and prone to internal condensation or rain water leakage through the fuel caps. And when fuel is mixed with a small amount of water it can increase the power stroke significantly to exceed the connecting rod or cylinder wall stress tolerance. And when the airplane crash and burn no one is going to find any water traces except those of the fire trucks.

How does a small amount of water mixed into the  fuel somehow cause so much extra power it destroys the engine?  Water is not flammable.  ADI water injection increases power because it increases the compression ratio and cools the flame front down, allowing you to run a little more supercharger boost...but this is not in any way related to that.

Another factor that can damage and engine on takeoff is an intermittent spark plug, plug cable or magneto. If there is no ignition during a power stroke on the next power stroke there could be more fuel in the cylinder causing a greater explosion thus more stress and failure.

Dude....seriously. One power stroke then fuel isnt lit, so that fuel hangs around, and the next stroke it fires this extra-rich mixture.. How can this destroy the engine?  Its not compressing it to twice the original value, its still the same 8.7:1...... in fact is less stress since its richer than full-rich...

 

I think you need to go back and read up some more, your post lacks basic physics and engine fundamentals.

[PTK]

Physics can be elusive. Philosophically speaking we have to distinguish between the laws of reality and the laws of theory. We see what we think is real but there’s also the theoretical reality behind what we see. This can give rise to new never thought of possible discoveries. Case in point: we’ve seen ethanol mixed in gasoline. The next big thing may very well be H₂O in av fuel  and may very well save GA. Just saying...  

[markejackson02]

It may have to do with how quickly people handle the throttle.  I advance mine as slowly as practical so it's not reaching full power until at or just before liftoff.  If you just cob the throttles, I'm sure it places some big stresses on the engine.

 

[PTK]

19 minutes ago, markejackson02 said:

It may have to do with how quickly people handle the throttle.  I advance mine as slowly as practical so it's not reaching full power until at or just before liftoff.  If you just cob the throttles, I'm sure it places some big stresses on the engine.

 

How well does that work for short field ops?

[markejackson02]

Just now, PTK said:

How well does that work for short field ops?

It's fine for the home drome which is 5,000' long.  For short field, just hold the brakes on until at 29 inches or so.

[jetdriven]

Jamming the throttle full open is hard on counterweights but taking 20 seconds to get to full throttle is trading a perceived gain in one area and transferring risk to another area. For example you need to verify full MP, 2700 RPM, oil pressure, fuel pressure, fueL flow ,etc before lifting off. But if you aren’t at full throttle until just before liftoff, you may be committed to takeoff with a compromised engine. 

3-5 seconds to full power is totally within acceptable practice. We used to run the TIO-541-J2BD engine in the Cheiftain that way and also the geared 421 engines. The TIO ran as much as 56” of MP.  The GTSIO-520 was turbocharged and geared. 

Edited April 12, 2018 by jetdriven

[Hank]

Ever watched an in-cockpit view of Bob Hoover flying a show? Half a second for WOT to ICO would be generous . . . .

[jetdriven]

From WOT to feather. And his engines made TBO on both sides. 

[RobertGary1]

The main reason for adding throttle slowly is because the Stromberg carbs couldn't keep up. They didn't have an accelerator pump and would bog, cough, spit if you advanced throttle too quickly. Its been a long time since I've flown a carb'd Mooney so I don't recall if that's the case with them or not.

 

-Robert 

Edited April 12, 2018 by RobertGary1

[Aviationinfo]

Here’s an interesting article, shared here just for fun and to add another perspective, on setting power for climbs.  

http://www.mooneypilots.com/mapalog/powersettings.html

[Aviationinfo]

PS:  I have read elsewhere that the engine-failure-due-to-power-reduction-after-takeoff scenario was really only applicable to radials;  it’s not an issue or it’s certainly less of an issue with these engines.  I can’t remember if that was from a Busch article, or Barry Schiff, or someone else.  I believe that we might be talking about engines where max horsepower is only allowed for a short time period.  That wouldn’t apply to these O or IO-360s.

My personal practice is to avoid power changes until 1000’ AGL or greater, simply to get above obstacles ASAP—-not because I worry about power reductions being detrimental.  I have used the WOT technique in the article in my previous post and find that it works well.   

Edited April 12, 2018 by Aviationinfo

[INA201]

20 minutes ago, Aviationinfo said:

Here’s an interesting article, shared here just for fun and to add another perspective, on setting power for climbs.  

http://www.mooneypilots.com/mapalog/powersettings.html

Good article and makes sense. I’ve seen where other Mooney gurus and MS members take the same approach.  This approach certainly eliminates this discussion on power reduction.

[jlunseth]

24 minutes ago, Aviationinfo said:

Here’s an interesting article, shared here just for fun and to add another perspective, on setting power for climbs.  

http://www.mooneypilots.com/mapalog/powersettings.html

I read that article, and speaking from the turbo point of view it made the hair stand up on the back of my neck.  I hope no offense to Bob Kromer.  But it says, "But be careful - if CHAT or Oil Temps approach 20 degrees or so of redline be ready to back off the manifold pressure."  Any non-231 pilots happen to know what the CHT redline is for a 231? I know because I visited it once upon a time.  Its 460!!!  Yikes.  Then it says," It's unfortunate, but full rich fuel flows are sometimes set by the manufacturer to cool the engine with fuel."  Its true that full rich fuel flows for turbos are set high, but the high setting does not "cool the engine with fuel."  The high setting acts in much the same way as a LOP setting (no, don't ever climb LOP), by slowing the rate of combustion, thus stretching the ICP curve out, reducing the heat generated in the cylinder and generally being much nicer to the cylinder.  He then recommends leaning to 125 ROP for climb, but says watch the temps and if they get high pull the MP.  

No wonder so many 231's never made it past 1200.  There was this idea that it was ok to let the cylinders cook up to 440 before doing anything about it.  And that full rich in the climb was just fuel inefficient because the fuel washed the cylinder and cooled it, and we wanted to be efficient, so lean it out and let the temps climb.

Climb in the turbo is full power, full RPM, full rich, fully open cowl flaps and keep your climb rate low enough to generate sufficient cooling air flow over the cylinders.  If it happens to be a very hot day an full everything is not keeping the temps down, then lower your climb rate first.

On the supposed risk of reducing power during the climb, and worrying about whether that will upset the engine, supporting the supposition that this is the reason for engine outs during takeoff, has anyone considered that the regime of flight where we most often reduce throttle is not climb, but descent and approach. So why don't aircraft fall out of the sky with regularity when we are, say, in level low altitude flight a full cruise power, and a few miles from the airport we cut the power to get to approach speed in the pattern.  Seems to me they should be falling like proverbial flies at that point.

[RobertGary1]

I don’t think anyone is saying any of this is with regularity. At least in my case I’ve had more engine failures during takeoff than other phases. Maybe I’m an anomaly but it’s also likely that power issues at cruise reducing for decent are less impacting and don’t make the news as much as low altitude power losses at take off 

-Robert

[Aviationinfo]

1 hour ago, jlunseth said:

I read that article, and speaking from the turbo point of view it made the hair stand up on the back of my neck.  I hope no offense to Bob Kromer.  But it says, "But be careful - if CHAT or Oil Temps approach 20 degrees or so of redline be ready to back off the manifold pressure."  Any non-231 pilots happen to know what the CHT redline is for a 231? I know because I visited it once upon a time.  Its 460!!!  Yikes.  Then it says," It's unfortunate, but full rich fuel flows are sometimes set by the manufacturer to cool the engine with fuel."  Its true that full rich fuel flows for turbos are set high, but the high setting does not "cool the engine with fuel."  The high setting acts in much the same way as a LOP setting (no, don't ever climb LOP), by slowing the rate of combustion, thus stretching the ICP curve out, reducing the heat generated in the cylinder and generally being much nicer to the cylinder.  He then recommends leaning to 125 ROP for climb, but says watch the temps and if they get high pull the MP.  

No wonder so many 231's never made it past 1200.  There was this idea that it was ok to let the cylinders cook up to 440 before doing anything about it.  And that full rich in the climb was just fuel inefficient because the fuel washed the cylinder and cooled it, and we wanted to be efficient, so lean it out and let the temps climb.

Climb in the turbo is full power, full RPM, full rich, fully open cowl flaps and keep your climb rate low enough to generate sufficient cooling air flow over the cylinders.  If it happens to be a very hot day an full everything is not keeping the temps down, then lower your climb rate first.

On the supposed risk of reducing power during the climb, and worrying about whether that will upset the engine, supporting the supposition that this is the reason for engine outs during takeoff, has anyone considered that the regime of flight where we most often reduce throttle is not climb, but descent and approach. So why don't aircraft fall out of the sky with regularity when we are, say, in level low altitude flight a full cruise power, and a few miles from the airport we cut the power to get to approach speed in the pattern.  Seems to me they should be falling like proverbial flies at that point.

Your point is very well taken.  I wouldn’t let my normally aspirated cylinders get that hot either.  The magic number is apparently 400 and the prevailing advice seems to be to use some margin below that, like 380, as a safe maximum.

Even normally aspirated cylinders have ridiculously high red lines, but that doesn’t mean it’s ok to fly them right up to that temp.

[jaylw314]

1 hour ago, Aviationinfo said:

PS:  I have read elsewhere that the engine-failure-due-to-power-reduction-after-takeoff scenario was really only applicable to radials;  it’s not an issue or it’s certainly less of an issue with these engines.  I can’t remember if that was from a Busch article, or Barry Schiff, or someone else.  I believe that we might be talking about engines where max horsepower is only allowed for a short time period.  That wouldn’t apply to these O or IO-360s.

I think you're talking about a Mike Busch article. 

In it, he comments that "At full power, the engine runs cooler than at reduced power because it gets more fuel for cooling."  I'm a little suspect about that statement--I think he's referring to fuel systems that have an enrichment valve when the throttle is WOT, so reducing throttle from that will lean the mixture.  Otherwise, there's no reason I can think of that an engine would run cooler at full power.  AFAIK, I don't think IO-360's have an enrichment valve

[Aviationinfo]

5 minutes ago, jaylw314 said:

I think you're talking about a Mike Busch article. 

In it, he comments that "At full power, the engine runs cooler than at reduced power because it gets more fuel for cooling."  I'm a little suspect about that statement--I think he's referring to fuel systems that have an enrichment valve when the throttle is WOT, so reducing throttle from that will lean the mixture.  Otherwise, there's no reason I can think of that an engine would run cooler at full power.  AFAIK, I don't think IO-360's have an enrichment valve

I bet you’re right.

I believe the enrichment facility applies only to carbureted engines.  I’m just guessing but injected engines probably have a target fuel flow at full rich at max power, that provides for cooling.

Edited April 12, 2018 by Aviationinfo