Multiengine question

[flyingcheesehead]

I must pose the question, and invite all MEI's and multiengine pilots to answer: You have an engine issue during departure (just after takeoff, so no putting it back down on the runway). You circle back to make a landing, but you manage to get the engine to produce full power again before you're even on downwind, so you keep climbing and proceed on your original planned course.

A half hour later, you come to the shore of a big, cold lake. Both engines have been operating at full power for a significant length of time. What do you do?

Comments welcome...

 

[HomeatFL250]

I would say always get it back down and get it looked at, and then count your blessing that you had two engines to bring it back around.

 

[Steve]

Is this a Sunday drive, or are you flying to Tokyo with Doolittle?

 

[Bill]

Is this a Sunday drive, or are you flying to Tokyo with Doolittle?

Those animals at Ueno Zoo must need a serious talking to.

 

[Ken Ibold]

There's a whole lot of wiggle room between "working properly" and "seems to be fixed." Perhaps I'd press on over friendly terrain with lots of close together airports, such as Florida has. But over a Great Lake? No thanks!

 

[Henning]

I must pose the question, and invite all MEI's and multiengine pilots to answer: You have an engine issue during departure (just after takeoff, so no putting it back down on the runway). You circle back to make a landing, but you manage to get the engine to produce full power again before you're even on downwind, so you keep climbing and proceed on your original planned course.

A half hour later, you come to the shore of a big, cold lake. Both engines have been operating at full power for a significant length of time. What do you do?

Comments welcome...

Well, my answer is to keep going at that point, but it requires an assumption that isn't covered, and that is I know WHY I lost power to begin with. If I had mysteriously lost and regained power, I would have never aborted my approach the first time after failure. If I regained power because I switched the fuel selector from "OFF" to some functioning tank, then no problem. The qualifier is always in the "WHY".

 

[Flyboy]

Personally, I you left off my answer, which was to not procede at all but land at the airport of departure and try to find out what happened.

 

[Bill M.]

Land and get it checked if I wasn't absolutely sure what the problem was and why it "fixed itself."
Bill, MEI

 

[SCCutler]

(Piece a crap, did not save my answer!)

What Henning said-

My answer, that I would continue on across, is predicated upon the presumption that the "problem" which was cured immediately after departure was a trivial and obvious one, something like feeding from an empty tank or pulling a mixture lever instead of a prop lever, that sort of thing.

Had it been otherwise, I would have returned and landed, as a precaution, and never reached the lake in the first place.

 

[colomtnflyer]

I think I'd have to hang with Henning on this one... Why the engine had problems to begin with is a greater issue than pushing forward across water...

Only if I was completely satisfied that I was the cause of the problem, and that I had corrected it completely, would I even consider continuing on with the flight. Anything else, I'm heading back to the hangar!

 

[flyingcheesehead]

Here's why we didn't just land right away: The engine went almost as soon as we were out of usable runway. We had to keep climbing to at least make it around the pattern. Joe got it working in a hurry, and I continued climbing. Altitude = options.

So, by the time I'd completed the circle, we were at 4,000 feet over the airport and the engine had been operating just fine for the last couple thousand. Barring an emergency, which IMHO this was not ("bad" engine producing full power, other engine still operating just fine, and directly over an airport), why risk destroying the other engine by pulling power and dropping back down? There's another airport directly on our route that would be more suitable, let's head that way and see what the engine does.

Now I'm one of the more conservative people I've met when it comes to crossing the lake. (Any more conservative = don't ever cross.) Of all the ways to die, taking a cold bath is last on the list. If it came to that, I'd probably point the nose straight down instead.

So when the engine had been operating just fine for a while... I felt perfectly comfortable crossing the lake. We did start with two, there's still two there, and that's why we're flying a twin. Obviously Joe was comfortable with it too, and he's by far the most conservative CFI at the home drome.

Maybe it's just different when it's your own butt up there in the seat, or maybe I'm just stupid.

 

[Ken Ibold]

Here's why we didn't just land right away: The engine went almost as soon as we were out of usable runway. We had to keep climbing to at least make it around the pattern. Joe got it working in a hurry, and I continued climbing. Altitude = options.

Just out of curiosity, what were the power loss symptoms and what did he do to get it working again?

 

[Baron 55]

Not a slam dunk to answer; I'd need to know what troubleshooting got the engine working again. But I wouldn't feel comfy continuing on the flight until I landed back at original airport and gave the plane a good going over unless the original problem seemed to be something like fuel mismanagement or other screw-up I'd made in managing the engine and that I discovered. I mean, if it was one of those "Duh!" moments I might continue on the flight, but not if it was some mysterious "it sorta just started working again" deals. Having the two engines makes it possible to delay that landing just a bit while you ponder things.

 

[jesse]

Just out of curiosity, what were the power loss symptoms and what did he do to get it working again?

Sounds like the "bad" engine was getting way too much fuel. So he pulled the mixture back on the "bad" engine which caused it to run fine. Both engines were then reading the same fuel burn.

 

[flyingcheesehead]

Just out of curiosity, what were the power loss symptoms and what did he do to get it working again?

The details are in the "Getting to know the Seneca" thread. Basically, power was reduced on the left. Only symptoms were the right rudder I had to put in (It wasn't sudden, there wasn't a big yaw like when you pull an engine all at once) and the fuel flow going all the way up to the peg. Something got jammed in the fuel controller and so the engine was running super-rich. Joe leaned the mixture to match fuel flows and it ran fine again.

There was no drop in MP or RPM, no roughness or anything like that. I don't have enough experience with the Seneca to give a good estimate of how much power was lost due to the ultra-rich mixture, but there was definitely still partial power, and full power once the mixture was correct again.

 

[Dave Siciliano]

Kent:

I don't know the Seneca well enough to be confident. If there's a control problem (cable or whatever) and I was confident I could deal with it; I'd proceed. However, if there was any question, I'd get the plane down. How it was operating might make me think about getting to a good repair facility as opposed to an uncontrolled, no facility field.

To go out over a large body of water with a known issue would not be my choice unless I really understood the problem and knew I could deal with it.
Otherwise, let's have someone look it over and tell me it's O.K. to proceed or needs to be fixed.
Best,

Dave

 

[flyingcheesehead]

I must add one more thing.

Had I been flying by myself, I'd have put it right back down at CAD. Trying to fly, AND diagnose the engine problem could have been disastrous. Having two pilots aboard was a BIG help. CRM, baby!

 

[ApacheBob]

Pretty serious pucker factor in losing an engine just off the end of the runway.
It's kind of a "seat-of-the-pants" issue, just like other people are saying.
What did it sound like when it quit? If it made a lot of other noises, could be pieces of something pinging around in the engine compartment. If it sputtered because of a seemingly-minor mixture issue, who knows.
It is pretty easy to say you would "never" do this or "never" do that, but when the event actually occurs, folks tend to go with their gut feeling.
ApacheBob

 

[bbchien]

I must pose the question, and invite all MEI's and multiengine pilots to answer: You have an engine issue during departure (just after takeoff, so no putting it back down on the runway). You circle back to make a landing, but you manage to get the engine to produce full power again before you're even on downwind, so you keep climbing and proceed on your original planned course.

A half hour later, you come to the shore of a big, cold lake. Both engines have been operating at full power for a significant length of time. What do you do?

Comments welcome...

Depends entirely on what the cause was. Depends on whether it's ascertainable in the air....with certainty.

 

[gismo]

Well, my answer is to keep going at that point, but it requires an assumption that isn't covered, and that is I know WHY I lost power to begin with. If I had mysteriously lost and regained power, I would have never aborted my approach the first time after failure. If I regained power because I switched the fuel selector from "OFF" to some functioning tank, then no problem. The qualifier is always in the "WHY".

That works for me as long as the pilot doesn't confuse "believe" with "know". As I posted in the thread that spawned this poll, it's common for pilots to make assumptions about engine or other problems in the air when there's really no way to know for sure what the cause was. Certainly if there was an engine control improperly configured and putting that control where it should be restored normal engine operation, you've got sufficient evidence that the actual problem has been corrected. But just because you find a way to adjust the controls so that the engine appears to be running fine, and said adjustment supports your theory as to the root cause, shouldn't be justification for confidently continuing the flight.

And if you are flying a twin because you appreciate the redundancy of a second engine, you need to realize that you probably just through that redundancy away if you are really just guessing why the hiccup occurred.


P.S. this opinion isn't meant as a criticism of Henning's post (which I pretty much agree completely witn).

 

[gismo]

I must add one more thing.

Had I been flying by myself, I'd have put it right back down at CAD. Trying to fly, AND diagnose the engine problem could have been disastrous. Having two pilots aboard was a BIG help. CRM, baby!

Actually CRM value aside, this sounds like a situation where you allowed yourself to get into a potentially bad situation because you delegated all responsibility for the safe completion of your flight to the CFI in deference to his greater experience and qualifications. One of the tenets of CRM is that while one pilot must be PIC, the general rule is to go with the more conservative opinion of the two pilots to offset the tendency to do just the opposite.

 

[flyingcheesehead]

What did it sound like when it quit? If it made a lot of other noises, could be pieces of something pinging around in the engine compartment. If it sputtered because of a seemingly-minor mixture issue, who knows.

It was very benign. Engine didn't sputter, MP and RPM stayed the same, but I had to put right rudder in and the fuel flow went way up. Sure seemed minor.

It is pretty easy to say you would "never" do this or "never" do that, but when the event actually occurs, folks tend to go with their gut feeling.
ApacheBob

Bingo. And this chicken didn't think twice about crossing the lake 20 minutes later.

 

[flyingcheesehead]

One of the tenets of CRM is that while one pilot must be PIC, the general rule is to go with the more conservative opinion of the two pilots to offset the tendency to do just the opposite.

Both of our opinions were the same... What's that mean?

 

[Henning]

It was very benign. Engine didn't sputter, MP and RPM stayed the same, but I had to put right rudder in and the fuel flow went way up. Sure seemed minor.

I'm not quite understanding this, here is what I think you're telling me... Engine was running way to rich so it lost power and the MEI pulled back the mixture on that engine till it ran smoothly. If that is correct, at that point was there a large disparity between the mixture levers? One more thing, are you being paid to fly this plane, or are you paying for it?

If there was a big gap between the levers and I was paying, I would have returned to base. It spells fuel servo to me (you're the command pilot, you have to assume worst until better is proven). Is the CFI a GOOD A&P/IA? If not he sure as hell isn't making a mechanical go/no go for me. Sorry, but most CFIs I know and meet are mechanical morons. I hear them explain systems to students and I cringe. If there was more than a 1" split in the mixtures, that plane would not have crossed the lake without me being payed at my hazard rate.

 

[Aztec Driver]

I would have to agree with the majority, it depends on what fixed it. I can tell you one thing, if an engine produces little or no power after liftoff and in the climb prior to a "reasonable" altitude, that prop is being feathered and there won't be any determining of the problem prior to landing. If I got to altitude before it failed, then I would take the time to figure it out, and it would have to be a fault of my own making, not a "magic fix."

 

[flyingcheesehead]

I'm not quite understanding this, here is what I think you're telling me... Engine was running way to rich so it lost power and the MEI pulled back the mixture on that engine till it ran smoothly.

Yep.

If that is correct, at that point was there a large disparity between the mixture levers?

If there was more than a 1" split in the mixtures, that plane would not have crossed the lake without me being payed at my hazard rate.

Naah, not that big. Top of one knob at the bottom of the other, roughly.

One more thing, are you being paid to fly this plane, or are you paying for it?

If there was a big gap between the levers and I was paying, I would have returned to base.

Yes, paying for it... And return to base is exactly what we did - That's where we were headed anyway. Or did you mean return to the field we left from on that particular flight?

Sorry, but most CFIs I know and meet are mechanical morons. I hear them explain systems to students and I cringe.

Again, Joe's not like that. He spends a lot of time in the shop, knows every one of the mechanics fairly well, and drags me down there on a regular basis (quite willingly, mind you!) to show me things and we chat with the A&P's. He also used to own an airplane and catches things on preflight that I'd never see.

 

[gismo]

Both of our opinions were the same... What's that mean?

Probably that both of you were overly impressed with the other's ability to cope with the problem if it got worse.


I was actually responding to your statement...

Had I been flying by myself, I'd have put it right back down at CAD.

...which made me think you thought the flight should be terminated but your CFI convinced you to continue. Sounds like that was an incorrect interpretation, but I stand by my belief that two pilots are likely to accept greater risk together than either would take on if they were by themselves.

 

[gismo]

It was very benign. Engine didn't sputter, MP and RPM stayed the same, but I had to put right rudder in and the fuel flow went way up. Sure seemed minor.

Sorry Kent, but baring a connecting rod breaking, a total loss of oil pressure, or a big engine fire, that's exactly what almost any engine failure in a twin looks and sounds like.

 

[flyingcheesehead]

Probably that both of you were overly impressed with the other's ability to cope with the problem if it got worse.

I don't think my CFI thought I would be able to cope with the problem any better, it being only my third flight in the airplane.

I was actually responding to your statement...

...which made me think you thought the flight should be terminated but your CFI convinced you to continue. Sounds like that was an incorrect interpretation

Ah, OK. What I meant when I said I would have put it back down at CAD had Joe not been with me is that I wouldn't have been able to both fly AND deal with the engine problem on my own, so I'd have focused on the flying part and just put it back down before trying to deal with the engine.

 

[Henning]

Yes, paying for it... And return to base is exactly what we did - That's where we were headed anyway. Or did you mean return to the field we left from on that particular flight?

Return to field or stayed over land. Again, you didn't know WHY you had the problem or WHY leaning fixed it. It was a DUMB decision to continue and you got lucky. Had it been contaminated fuel you could have ended up losing both. The decision you both came to was improper. If I was being PAID to ferry the plane, I would have figured out WHY I had this condition. Was it Ice in a fuel servo? Just too much unknown to be winter over water in a plane that glides like a brick.

 

[flyingcheesehead]

Okay...

Now, another question.

Of the 20 people that responded to the poll, only ONE said to put the plane down right away.

Half said to return to the field of origin (20 minutes away).

But, 19 of 20 chose an option that involved continued flight in some form or another. Considering the beating I've taken on this issue, I have to ask.. WHY?

In fact, the people that chose the "keep flying but go around the lake" are the ones that confuse me most. At this time of year, putting the plane down ANYWHERE but an airport has a high likelihood of causing death by exposure. So, with an engine which people are telling me I shouldn't have been relying on, why would I increase my exposure by making the flight over twice as long?

 

[flyingcheesehead]

Return to field or stayed over land. Again, you didn't know WHY you had the problem or WHY leaning fixed it. It was a DUMB decision to continue and you got lucky.

I can see that there was a chance of the left engine going again, but given that it ran just fine for 20 min before we got to the lake led me to have some confidence in it.

How unlucky would we have to be, to have that engine go again after it was running fine for a length of time, AND lose the other one within three minutes? The symptoms did not indicate fuel contamination. What other possible causes would there be for dual engine failure?

 

[gismo]

Okay...

Now, another question.

Of the 20 people that responded to the poll, only ONE said to put the plane down right away.

Half said to return to the field of origin (20 minutes away).

But, 19 of 20 chose an option that involved continued flight in some form or another. Considering the beating I've taken on this issue, I have to ask.. WHY?

In fact, the people that chose the "keep flying but go around the lake" are the ones that confuse me most. At this time of year, putting the plane down ANYWHERE but an airport has a high likelihood of causing death by exposure. So, with an engine which people are telling me I shouldn't have been relying on, why would I increase my exposure by making the flight over twice as long?

WRT putting the plane on the ground ASAP, that's for engine fires and other life threatening situations (pax with heart attack etc). Flying to the departure airport 20 miles behind you, or another airport within a similar range that has better runways and/or maintainence facilities with one very suspect engine (or even one caged engine) on a twin bears little risk IMO and would probably have been my choice in the situation you described. Flying any great distance unnecessarily with a pending engine problem increases the risk of serious consequences if things get worse and I wouldn't recommend that either (going around the lake). But flying beyond gliding distance from land over a body of water that's cold enough to guarantee you won't survive if you ditch increases that risk to exceptionally unacceptable levels for me. I used to cross the lake in a Bonanza, but I did it with enough altitude to be able to reach knee deep water or land without the engine from any point in the crossing. And even though there are pilots who will take the risk of flying beyond gliding range, you have to consider that when an unknown problem occurs with a twin, there's a distinct possibility that both engines will be affected down the road especially if it's fuel related and IMO only the most foolhardy pilot would knowingly fly well beyond gliding range of land in a single with an unexplained engine problem. I realize it didn't seem like that to you with both engines "running fine" after an unusual mixture adjustment, but I believe that given you were really only guessing about the cause of your problem, you really were pretty much flying a single with an undiagnosed engine problem. I assume you don't dispute the fact that your chances of surviving a ditching were practically nil. I'm also assuming (without any supporting evidence) that you didn't use the Seneca's ability to fly high enough to glide to shore during the water crossing. Had you done that, I'd agree your risk was fairly low.

 

[Aztec Driver]

Okay...

Now, another question.

Of the 20 people that responded to the poll, only ONE said to put the plane down right away.

Half said to return to the field of origin (20 minutes away).

But, 19 of 20 chose an option that involved continued flight in some form or another. Considering the beating I've taken on this issue, I have to ask.. WHY?

In fact, the people that chose the "keep flying but go around the lake" are the ones that confuse me most. At this time of year, putting the plane down ANYWHERE but an airport has a high likelihood of causing death by exposure. So, with an engine which people are telling me I shouldn't have been relying on, why would I increase my exposure by making the flight over twice as long?

Well, in revisiting the poll, I , and presumably most others, assumed that your engine problem happened immediately after takeoff and the "airport of depature" was the one directly behind you. I think that all of the 10 respondents in that category believe you to be returning to the airport directly behind you, not to one that you left previously. I could be wrong, though. That was my take on it anyway. That would make it 11 of 20.

Your further statement that the mixtures were only split by less than a knob's width adds a lttle strength to your argument, as quite a few of the planes I have flown require slightly separate mixture adjustments for "proper" running. They don't, however, lose power on one engine because of it. I stand by my choice of returning to the airport of departure (directly behind you) unless you know what caused the problem in the first place.

One lesson that is very difficult to learn is the ability to make a command decision that goes against a very experienced pilot. Remember, though, that the experienced pilot, because of his/her experience, may feel comfortable with risks a lot higher than your own. After review of some incidents with a very experienced CFII pilot friend of mine, I chose to NEVER let him dictate any command decisions that I felt were wrong or were uncomfortable with. You need to carefully review this incident and decide for yourself whether or not it was wise to continue.

What were your options if the problem had not been truely repaired?

 

[Henning]

I can see that there was a chance of the left engine going again, but given that it ran just fine for 20 min before we got to the lake led me to have some confidence in it.

How unlucky would we have to be, to have that engine go again after it was running fine for a length of time, AND lose the other one within three minutes? The symptoms did not indicate fuel contamination. What other possible causes would there be for dual engine failure?

How lucky do you count on being? Why do you not think this problem could have been caused by ice in the fuel/fuel servo, explain the functioning of the fuel servo to me, actually explain the entire Bendix F.I. system to me. What would cause the fuel servo to go overly rich, give me all the reasons and then tell me which one you chose and why.

Aviation is not a game where you rely on luck. Aviation is where you do everything right, and pray that luck covers your mistakes. You get six mistakes in a chain, then you die.

 

[flyingcheesehead]

WRT putting the plane on the ground ASAP, that's for engine fires and other life threatening situations (pax with heart attack etc). Flying to the departure airport 20 miles behind you, or another airport within a similar range that has better runways and/or maintainence facilities with one very suspect engine (or even one caged engine) on a twin bears little risk IMO and would probably have been my choice in the situation you described.

Doh! Both "fields" in the poll are airfields. Paved runways, etc. Not a farm field. Should have been clearer on that.

I used to cross the lake in a Bonanza, but I did it with enough altitude to be able to reach knee deep water or land without the engine from any point in the crossing.

Turbo and oxygen, I assume? What's the glide ratio on the Bo? Where did you cross?

Where I cross to go to CAD, ideal conditions and assuming a 9:1 glide, 15,500 feet is the absolute minimum to glide near shore... And I have no oxygen.

[quoteI'm also assuming (without any supporting evidence) that you didn't use the Seneca's ability to fly high enough to glide to shore during the water crossing.[/QUOTE]

Nope. It doesn't have oxygen built-in, and I'm not going to buy an oxygen system for a flight or two a year in a rental plane.

Next time, maybe I'll take the TwinStar from UGN. It'll go high and glide better.

 

[flyingcheesehead]

Well, in revisiting the poll, I , and presumably most others, assumed that your engine problem happened immediately after takeoff and the "airport of depature" was the one directly behind you.

The problem did happen immediately after takeoff, but the departure airport was not the one right below us for the purposes of this question. When the engine was developing full power again, we decided to keep flying and see what happened.

Had we left from Manistee (the airport right beneath us as we were arriving near the lake shore), maybe things would have been different.

The question was basically not a "what to do right now" but instead, "Given that we're in this situation where the engine has been running fine for the last 20 minutes, what should we have done."

Part of the problem with asking a question like this is that it wasn't one decision that led us to cross the lake, it was many decisions over a span of time.

One lesson that is very difficult to learn is the ability to make a command decision that goes against a very experienced pilot. Remember, though, that the experienced pilot, because of his/her experience, may feel comfortable with risks a lot higher than your own.

That's just the thing... I would have gone. When I stated earlier in the thread that I'd have put it back down if I were solo, that was simply due to workload issues - If I could have made the same fix in the air, and I was the only one making the decision, I still would have gone through the same process and done the same things.

 

[tonycondon]

hmmm this reminded me of an old article Matt showed me. A little researching reminded me of the specifics. At either the 1938 or 1939 National Soaring Meet in Frankfort, Michigan, Ted Bellak took an aerotow to 18000 feet and became the first (and maybe only!) glider to cross the lake. Now days you wouldnt have to go as high. The gliders of that era werent particularly high performance.

 

[flyingcheesehead]

explain the functioning of the fuel servo to me, actually explain the entire Bendix F.I. system to me. What would cause the fuel servo to go overly rich, give me all the reasons and then tell me which one you chose and why.

Me stoooopid.

So, it's education time, as I need to learn this. How does the fuel injection system work? I have only a basic knowledge.

What I'm especially interested in... What are the failure modes that could cause a dual engine failure on a Seneca. So far, I can think of...

1. Pilot error in its many forms (both on crossfeed, crossfeed in the wrong direction after engine failure, pulling the mixtures, incorrectly identifying and shutting down the wrong engine, etc. etc.)
2. Fuel contamination.
3. ??? (I'm not in much of a thinking mode yet today, got home at 3:30 AM)

 

[bbchien]

I can see that there was a chance of the left engine going again, but given that it ran just fine for 20 min before we got to the lake led me to have some confidence in it.

How unlucky would we have to be, to have that engine go again after it was running fine for a length of time, AND lose the other one within three minutes? The symptoms did not indicate fuel contamination. What other possible causes would there be for dual engine failure?

Well, it could have been running rough from oil flooding the mag seal and taking out one of the mags. You richen/lean the mix enough to get smooth combustion with teh delayed flame fron spread. Then as 25 minutes went by, the casing floods entirely. Now you have one mag.

Or, you could have lost a tooth in the drive gear. When running at steady rpm, the mag has enough momentum to not get outta synch (whereas a lower powers it intermittently does). Then you cross the lake and you shear off 50% of the drive gear teeth. You've see a posted picture of that mag gear. Gotta box the engine while you still have 800 rpm.

It's a very very cold lake. IMO your instructor did you no favors. My SE student came to me after I aborted a landing at a 40 nm away airport, because "I was not going to depart VYS with a known mag problem". We turned around and came home; and then drove to VYS. Cost me a whole afternoon.

But it did teach my student about appropriate decision making. There was NO REASON we had to be at VYS at 10:00 am. Nobody was going to die if we were 2 hours late.