Loss of power after takeoff

[kevinw]

I had an interesting / scary flight yesterday and I'm trying to make sense of it. I was out "blowing the cobs" out in my '82 J which I typically do if I don't have anywhere to fly to. I like to fly my plane once a week. I took off and uneventfully climbed to 6500 and basically did some sightseeing south and west of where I'm based out of. After about 45 minutes I descended down to pattern altitude and made my landing. I taxi in and the airport manager tops off my tanks with about 35 total gallons of fuel. I decided to go back out and do some practice TOLs so I started the plane up and taxied to rwy 31. I did a mag and ignition check (I have an electronic ignition), set flaps, boost pumps on and lined up on the centerline for takeoff. I gave full throttle like always and lifted off at about 65 knots or so. Here's where it gets weird; I feel on liftoff things don't seem right. I'm not climbing like I normally do. It almost felt like a takeoff with no flaps. I get about 2-300' off the ground and I'm having trouble climbing. The first thing that comes to mind is "what did I forget!" Gear and takeoff flaps are still down because I'm sensing trouble. I immediately check that mixture and prop are fully in and the boost pump is on. They are. All gauges look normal; MP and RPM are good and the engine "sounds" like it operating normally. Airspeed is low and now I feel like the day has finally come where I may be making a forced landing. I try as best as I can to level the plane and try to pick up airspeed by keeping everything firewalled. At this point I feel like I'm not losing altitude but not gaining any either. So I now gear up and then flaps up. My heart is racing so I take a deep breath and tell myself to fly the airplane. I make a shallow, coordinated, somewhat nose down left turn back to the airport and by the time I'm parallel with the runway I'm at pattern altitude and it seems to be performing better; I know I can make the landing. I land the plane and pull off the runway. I check all the gauges on the EDM830 as well as the steam gauges, all normal. I do another run-up and check the mag, EI and prop. All normal. I decided to go back and give it takeoff power with the engine monitor set to fuel flow thinking the only possible cause is fuel starvation. If anything goes wrong I'll abort the takeoff and with a 5000' runway I have that option. Engine power and thrust seems normal this time so I continued the takeoff and I easily climbed to our pattern altitude of 2000'. I made the landing and repeated it again. Once again, normal. 

I downloaded the JPI data to see if it would give me any indication of what went wrong. I'm new to the EZ trends but I don't see anything. The engine monitor is new so the fuel flow is not accurate yet; I should be getting 18gph on takeoff. I compared the data to previous, normal flights and the fuel flow and HP are slightly lower but not much. 0.1-0.2 on FF and 2%HP. The highlighted line is about where the trouble began. 

So my question is this: Is it possible that the engine can be running at almost 2700 RPM with MP at 27 but not produce thrust? The only thing I did between everything normal and this was add fuel. I sampled all three sumps suspecting a fuel problem but it looked blue/normal and no water appeared. I have to tell you guys, this scared the hell out of me. In case anyone is thinking power on stall there's no way. The climb was shallow and the AOA was within normal range. The additional fuel added 210lbs but I was well below gross weight. The engine is a IO360 A3B6 with 140 hours SFRM. It was a clear day, about 60 degrees out with winds 290 at 12. I'm a 500 hour pilot with an IR and about 130 in this plane. I've never experienced anything like this before, in any aircraft. Any help is certainly appreciated. -Kevin

[Oscar Avalle]

What electronic ignition system do you have?

[M20F]

What did the airspeed and VSI indicate?

[BillC]

You didn't mention cycling the prop on the first takeoff.  Maybe the prop went coarse?

 

[kevinw]

I have the electroair system and it's worked flawlessly. I checked it before and after the flight but I won't lie, I wondered if it stopped for some reason. Airspeed was in the 70s as you can see in the pic under SPD. Little or no VSI.

[kevinw]

3 minutes ago, BillC said:

You didn't mention cycling the prop. Maybe the prop went coarse?

 

I'm not sure what that means but it felt like the the prop was pulled back; kind of like taking off in a car in 3rd gear. But if that were the case wouldn't the RPMs indicate that with a lower reading? I was so low to the ground I was afraid to touch much. I buzzed some houses and wouldn't be surprised if someone called the airport to report me.

[StevenL757]

Kevin - thanks for sharing your problem statement.  A few questions - probably stupidly basic.  You mention "blowing the cobs out", and that you like to fly weekly.  When was the last time you flew the airplane prior to your flight above?  Also, after refueling, did you sump fuel, and if so, how long after fueling did you wait to sump?

[kevinw]

3 minutes ago, StevenL757 said:

Kevin - thanks for sharing your problem statement.  A few questions - probably stupidly basic.  You mention "blowing the cobs out", and that you like to fly weekly.  When was the last time you flew the airplane prior to your flight above?  Also, after refueling, did you sump fuel, and if so, how long after fueling did you wait to sump?

Due to weather the last time I flew it was about 10-12 days prior. I did fly it for about 45 minutes just before. I rolled in, topped off the tanks but didn't sump. I just started it back up and taxied out. In a nutshell, it was like the engine was running normally but not producing full thrust. Just enough to keep it in flight and not much more. I would've been terrified if this happened in a major metro area. Luckily for me we have corn and bean fields everywhere.

[Bartman]

Is there a possibility you got Jet A fuel ?  

There was a thread here or AOPA about 2 weeks ago about accidentally getting Jet A.  I remember there is no way to tell it by color alone, and it will look like 100LL and will not separate.  However, I do not know enough about it to know how the engine would perform with a certain ratio of 100LL-Jet A.

[StevenL757]

Ok.  I like Bill's suggestion about a coarse prop & cycling vs. not.  Is there a possibility the prop control cable broke?  I've honestly never had that happen, but it sounds logical.  Sidebar comment - when cycling your prop, only do so slowly and until you see a 100-200RPM max drop.  I run into far too many people - most of them at my home airport - who "deep-cycle" their props.  The goal is to get just enough hot oil from the engine through the governor, and small RPM drops accomplish that nicely.  Pulling the thing back any more than that - to where the engine sounds like it's laboring or ready to quit is introducing excessive vibration that can do more harm than good.

[StevenL757]

1 minute ago, Bartman said:

Is there a possibility you got Jet A fuel ?  

There was a thread here or AOPA about 2 weeks ago about accidentally getting Jet A.  I remember there is no way to tell it by color alone, and it will look like 100LL and will not separate.  However, I do not know enough about it to know how the engine would perform with a certain ratio of 100LL-Jet A.

Good call, but probably not, given his reported performance.  If he had Jet A in there, we'd probably be having a different conversation...unfortunately.

[DonMuncy]

When you figure it out, make sure to report back. 

[kevinw]

I watched him put 100LL in so that's out. As far as the prop goes, I cycle the prop as you describe, very slowly until the RPMs drop and then quickly back in. I think I'll run out to the airport after work today and do another run up and prop cycle. The strange thing is I did two TOLs after the problem occurred and they were normal. I'm now wondering if something in the tank, like a piece of sealant, broke away and caused this. Just a guess...

[N601RX]

You mentioned the fuel flow had not been calibrated, was the manifold pressure calibrated?  To me it seems the takeoff MP was low for the 1100 ft of elevation your data files shows. If its reading correctly it seems like your throttle is not completely opening the butterfly in the servo. RPM was also about 40 rpm low, possibly due to lower engine power or perhaps a governor problem.  The engine seems to be running smoothly and on both mags just at a reduced power.  Also to help with future problems I would decrease the sampling rate from 6 seconds to 1 second.  It will help diagnose transient events if you ever have any.

[Oldguy]

I would also suggest uploading your data files to the Savvy Analysis web site to look at them. It makes looking at the individual slices easy and can let you see graphically how things looked at that specific time and compare them to the prior and subsequent TOLs.

www.savvyanalysis.com and you can use the free parts of the site. Feel free to post a screen capture of the flight in question back here. Easier for all of us to see and ruminate over.

John

[Yetti]

Flaps all the way down? Not that I would know about forgetting the flaps all the way down, they climb pretty poorly with the flaps all the way down.  So does a C172 not that I would know about that either.   Maybe the flap indicator has slipped a wire and not indicating properly

[CaptainAB]

Was it possible you forgot to return the magnetos to both after your run up?

[Marauder]

49 minutes ago, N601RX said:

You mentioned the fuel flow had not been calibrated, was the manifold pressure calibrated?  To me it seems the takeoff MP was low for the 1100 ft of elevation your data files shows. If its reading correctly it seems like your throttle is not completely opening the butterfly in the servo. RPM was also about 40 rpm low, possibly due to lower engine power or perhaps a governor problem.  The engine seems to be running smoothly and on both mags just at a reduced power.  Also to help with future problems I would decrease the sampling rate from 6 seconds to 1 second.  It will help diagnose transient events if you ever have any.

I agree on the MP. At 440' I am close to 30" MP during takeoff. I would expect closer to 29". His RPM is low but mine is in the same ballpark. 2680 is what I normally see at takeoff. 

Kevin -- you pull any other data for other flights to compare?

[PTK]

My theory is you topped off with some contaminated fuel. 

The specific gravity of 100LL is ~0.68 and that of jet A is ~0.83. That of water is 1.0. Therefore you may have had some trace jet A and/or water contamination that settled on the bottom of your tank and got picked up! Not enough to kill the engine but enough to give you the symptoms you described. Especially because you mentioned you didn't sump after topping off. And it cleared up by the time you turned back and were at TPA.

That's my theory and although I can't prove it I'm sticking to it! 

[Piloto]

Check the static alternate air push/pull knob. It does not take much to pull out by itself. If the knob was out the air speed indicator will indicate slightly higher airspeed. The higher indicated airspeed may induce you to try to climb behind the power curve thus a slower climb rate even at full power.

José

[1524J]

I had an experience not too long ago where I had climbed to cruise, got everything set, then settled in and was just flying along. I look down at my airspeed indicator and I'm only doing 120kts, look at my GPS and my groundspeed is low. I'm thinking my Mooney has turned into a Cessna! Then I look at my throttle.....I hadn't tightened the friction lock enough and it has backed out. You mentioned you checked your mixture and prop but didn't say anything about the throttle although I'm guessing that was just an oversight but it would certainly give the symptoms you've described.

Sounds as though you handled the situation well!

[kevinw]

Thanks for all the advice. I just returned from flying it again and everything is running normally. I spoke with the airport mgr who is also the CFII and the guy who fueled it. He's a bit puzzled as well. We talked about a partially plugged pitot tube, flaps at takeoff position and gear down then hitting a downdraft or perhaps the engine ingested a contaminant. I compared the data from previous flights and they are very similar. I will double check all the suggestions and when it goes in for annual next month talk to him about the low MP on takeoff. It's going up to Jedd-Aire in Benson MN. Jason is a Mooney expert so I'll pass all this info along to him. In the meantime I'll sump every time I fill, do careful runups and watch the engine gauges closely. You know....all the things we're supposed to do. If it happens again I'll let you guys know. Thanks again for all the input.

Sent from my iPhone using Tapatalk

[mooniac15u]

45 minutes ago, PTK said:

My theory is you topped off with some contaminated fuel. 

The specific gravity of 100LL is ~0.68 and that of jet A is ~0.83. That of water is 1.0. Therefore you may have had some trace jet A and/or water contamination that settled on the bottom of your tank and got picked up! Not enough to kill the engine but enough to give you the symptoms you described. Especially because you mentioned you didn't sump after topping off. And it cleared up by the time you turned back and were at TPA.

That's my theory and although I can't prove it I'm sticking to it! 

Jet A and 100LL are both mixtures of aliphatic hydrocarbons. As such they are miscible and the Jet A won't settle to the bottom. 

[DAVIDWH]

Great detective work from all the above.

Alt static knob not even on my check list.  Will remedy tomorrow.

Similar incident happened to me climbing out with a twin Cessna. Lucky for me only low roofs with no high smoke stacks.

In my case it was the prop governor gone out for pizza.

Best of luck with this gremlin.

 

[PTK]

20 hours ago, mooniac15u said:

Jet A and 100LL are both mixtures of aliphatic hydrocarbons. As such they are miscible and the Jet A won't settle to the bottom. 

I was referring to water more than jet A. You are correct. But jet A will not combust in piston engine.