Engine Failure yesterday

68 posts in this topic

Posted

Well I survived my first engine failure yesterday…. not quite EFATO. I departed Charlton Park at 14:15 and about 1000 feet QFE the engine spluttered, I made a 180 turn and by the time I finished the turn the engine died at 14:17. Pitch for 65mph put out a MAYDAY to all stations on Kemble’s frequency. Now you would think an Avid Speedwing (bit like a kitfox) would glide lovely…… Wrong. To maintain 65mph was 1200 foot a minute decent.

There was absolutely no way of making it back to Charlton Park. I had to pick a field. The problem is all the fields had either telephone cables or power cable across them…apart from two, and they stretched the glide. So now I was about 600 feet and things up to that point seemed slow motion. After 600 feet everything happened so fast. It became clear the field I wanted was no longer possible and the only field now available was about 200 meters long, dome shaped, ridge and furrow very long grass and hemmed in by 8-foot hedges and a scattering of trees with a house in it.

I clipped a hedge, but other than that was down safe and stopped slap bang in the middle of the field. At 14:20 I got out the plane and called Kemble on the landline to let them know I was safe with no damage to property or the aircraft.

Now I remember that after the initial MAYDAY a helicopter said they were in the area and would head over to find me. I then gave a running commentary over the radio of what was going on until I was at 600foot. My last comment was I will call on the landline if I made it safe. Thing that got me is initially how slow everything seemed to go and then speed of event after 600 feet. All that was going through my head was “find a field” and “pitch for speed” over and over again, all the way until touch down.

At about 100 foot I did not think I was going to make it and thought I was going in to the trees and hedges, when I clipped the hedges there was the field with a steep upwards slope right in front of me. I yanked back on the stick immediately which gave the softest of touchdowns I think I ever done!!
What did I not do, I never switched anything at all, No fuel, no electrics, nothing. I don’t think I panicked, although I am sure my MAYDAY probably sounded a bit excited. A few mins after calling Kemble on the phone I felt really really sick and that passed after about 10 mins.

What would I do different if it happened again? I am not sure I would/could do anything different to be honest.

Ah yes what caused the failure. I am not sure yet, but the fuel cap had come off at some point in the take off. The wing was covered in fuel, but the tank was not empty by any means. So, I kind of hope that it was something to do with pressure and the fuel venting out the wing instead of getting to the engine. Now don’t shoot me for not checking the fuel cap as a pre-flight check…because I did. The fuel cap is an old vintage style cap like that of a cub or old car. How it came off is a mystery to me.

I survived, property survived and the aircraft survived with a tiny hedge rash. Would be intrigued to hear comments and questions.

Hedge Rash:

oops.jpg

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Posted

Glad you made down o.k.  Great job on the landing.   Just a thought, 65 MPH seems high to me for best glide (mine, Kitfox, was more like 50).  What model Avid?

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Posted

MKIV Speedwing

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Posted

Sounds like you managed that very well. Thanks for sharing. Yes, the stress often (and better) come after, during it is all focus on the task at hand. Those who panic land hard...

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Posted

Very well done sir!

 

 

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Posted

Thinking about the possible cause of this... 

It sounds like the missing fuel cap is the cause creating a siphon preventing the normal fuel flow.

What kind of fuel pump do you have? If you have a vacuum operated membrane pump like a Mikuni just before the carburetors it sounds like it might need a new membrane and gaskets. It is obviously difficult to say but seen the normal suction power of those pumps I would have expected it capable to counterbalancing the venturi effect of the missing cap, particularly at takeoff speeds. 

...just a thought...    

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Posted

Welcome to the club and yes the speedwing does full fast and I'm glade you and the aircraft are in one bit.

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Posted

Well done Gfry.  Though we've all practiced these things many times one never knows how we'll react.  I recall an encounter with a 1000 bear when I worked in Alaska.  

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Posted

Short-speedwing with a dead motor?  Wow!  Those glide like a piano!

You've done a MAN'S JOB putting that thing down safe!  I'm very happy all went well and no injuries or major damage!

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Posted

Glad you made out ok.  I bet loosing the gas cap is what caused your problem.  JImChuk

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Posted

Gfri

I believe you did very well not to try switching anything....but instead fly and concentrate on landing. Indeed between an engine out at 1000ft and the landing you only have 45 sec to 1 minute to get things working for you. Any trial at starting the engine or troubleshooting would have precluded a good outcome for sure....my 2 cents and thank you for sharing.

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Posted

Nice job getting it on the ground!  I know having an electric back up pump saved my butt twice.  I now make the fuel pump rebuild part of the yearly condition inspection.  30 minutes and few bucks is worth the peace of mind to me.

:BC:

 

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Posted (edited)

What a great job getting it down. Nice piloting!

Classic fuel problem: The loss of the gas cap would remove the positive pressure on the gas in the tank, which helps force it down the tube to the header, and replaced it with a big negative pressure (which also whips the gas all over the wing). This probably caused the gas in the line to backup. If the header tank was then your fuel source, and was not being fed by the mains, it would exhaust in only a few minutes (a header tank made of 2.5" spar 20" long holds about 100 cubic inches, or about .43 gallons) at 6.5 GPH (edited) in climbout, the header will drain in no more than 4 minutes.

Cure? Gas cap retention, and an electric fuel pump that continuously feeds the Rotax pump (don't feel guilty, I bought one 2 years ago and it is on the shelf in my hangar, doing nothing to help!) A 4 psi pump can pull the gas enough to help break the "suction" that probably caused the problem.

Edited by nlappos
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Posted (edited)

<snip> holds about 100 cubic inches, or about .43 gallons) at 6.5 GPM in climbout, the header will drain in no more than 4 minutes. <snip>

 

Hmmmmm.  At 6.5 GPM I suspect we might drain a pair of 9 gallon tanks in about that time.....give or take.  But, I get what you mean. :D

Edited by Emory Bored

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Posted (edited)

Emory Bored, You read what I meant and not what I wrote, thank goodness! Every time I hit Enter I learn something new. I fixed the screw up.

Edited by nlappos
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Posted

Uh... We just talked about this in another string... Were you using a header tank with open vent?

I had forgotten how small the original "behind the seat" header tanks were... If that is what you had (with an open vent) an additional pump would not have helped as with reduced, or no, flow from the main tank the header tank would have filled up with air from the vent anyway. Never leave the header tank vent open!

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Posted

I'm not really sure how the Cessna 150 is plumbed but that has to be about the most reliable high wing fuel system ever devised.  I don't believe it has a header but it's cross vented somehow I think.  At least I think I think. 

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Posted

Congratulations on  a job well done.  I had a similar experience in my Speed Wing and your numbers were similar to mine.  Drop at 1200fpm and land at about 60mph.  I also clipped trees as I crossed a road to the field I had picked but dare not pull back as it would have stalled from the 30ft hieght.  Serious injury or worse.  I did have a bit of damage and after repairs immediately sold my Twitchy little Bit$h.  I now fly a Model IV and love it.  No more dropping out of the sky like a lead balloon.

Again Congratulations on a job well done.  I am glad we are able to offer back patting rather than condolances.  

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Posted

Few comments on a fuel pump.  I do have a Facet fuel pump. Funny enough I just reached 1000 feet and switched it off, it was  then that the engine died..... within seconds.

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Posted

...so the missing fuel cap prevented the gravity flow from working and without the pump the fuel started flowing back to the tank through the fuel line with immediate fuel starvation as result.

I'm not even going to ask if you tried to turn on the pump again, it was full of air and could most likely not restart the flow...

I know they look like toys but I really recommend to install Mikuni vacuum pumps if your engine is prepared for it (like Rotax, Simonini...). They are always on, takes little maintenance (and cheap to renovate) and pull as well as push.       

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Posted

I did  switch it on as soon as it started to splutter.  However it seemed useless as when I checked the header tank back on the ground it was bone dry.  My guess is the fuel venting backwards then created an airlock in the header tank.

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Posted

So this "when I checked the header tank back on the ground it was bone dry" is intriguing...

Scenario 1)
Assuming your header tank vent was open. No, or not sufficient, fuel came to the header tank due to the missing fuel cap once you reached some critical speed. The fuel used from the header tank was mainly replaced by air through the open went and the level in the header tank went down. With no gravity feed  (level in header tank lower than carburetors intake) the pump is required to feed the engine. Restarting the pump would fail if the header tank was empty.
Problems with scenario 1:
a) Unless turning off the pump coincided with the header tank being empty turning the pump back on again,as you did, should have (temporarily) solved the problem. 
b) If the header tank vent was open, the header tank should have filled up from the main tank once on the ground, but apparently it didn't...

Scenario 2)
Assuming your header tank vent was closed. The pump pulled fuel from the header tank and the header tank was back filled from the main tank (as with the vent closed only fuel can replace the fuel used).
Once the pump was turned off the flow went backward and killed the engine. We can assume air sucked in from the carburetor prevented the pump from restarting the flow.
Problem with scenario 2:
The header tank fill from the top so once the flow goes backwards only an amount of fuel corresponding to the volume between the engine and the header tank can be sucked back to the main tank. After that air will enter the header tank, move to the top and be sucked out to the main tank.
Even if the header tank was filled from the bottom it is unlikely that the header tank could have been emptied through the reverse flow during a 1000 ft speed wing decent. 

- So we need a 3rd scenario where the header tank could be empty once on the ground... 
Was your header tank vent open or closed and do you have a valve between main and header tanks that could have been "off"?
With 2 wing tanks I have a 3 way valve to select either the right or left tank and a middle position "off". Leaving that valve off cost me an imploded header tank (it was a plastic tank, sturdy but not comparable to the "metal tube" version). Luckily the engine choked at run up...
 

If you want to drop this subject just say so...

Fred  
  

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Posted (edited)

This is an interesting case to examine.  I have flown my MK IV without a fuel cap one time without ill effects.  On my plane I have a full time vent to the header tank and the engine driven fuel pump.  The trip was about ten miles plus a good mile of taxi time.  The plane has over 650 hours on it since I built it with this setup.  I'm not suggesting this setup to anyone else but it has worked. 

So the question I have is did the header refill when you vented it or have you tried that yet. One more question, does your plane have one or two wing tanks and were they both feeding the header at the time.  Just for comparison mine has two tanks and no valves between the tanks.

i have seen kinked fuel lines on a friends plane after folding and opening the wings that allowed fuel starvation 

The great new is that you kept your head and managed a safe emergency landing!

 

Hope this mystery is solved, there are valuable lessons here for all of us. 

Edited by wypaul
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Posted (edited)

ok, I have 1 tank.  I have a stop cock between the main tank and the header and I have a bleed valve to drain the header which is what I assume you are all calling a vent? part of my pre-flight is to bleed/vent the header for 10 seconds or longer if it needs to clear air.  Once I was back on the ground and prior to loading on to the trailer I needed to drain what was in the tank as it was sloshing out the wing when they were folded.  So I stuck a jerry can under the header tank and opened the bleed/vent valve.......it to quiet a while gurgling and bubbling and filling up before it started to bleed out the bottom.

Oh and I also have a fuel stop cock between the header tank and engine...roughly where the flapperon lever is.

Edited by Gfry
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Posted

Gfry,

Your fuel system is identical to mine. It is accurate to say that the holding tank serves as a debubbler, and not a vent. Any bubbles rise to the top, and you release them on the next preflight inspection. I believe my summary above is correct, in that the negative pressure from the missing cap  stopped the flow, and that the electric pump would fight this "suction" while it was on. Clearly the Rotax air pump didn't have the suction when acting alone.

Again, great job handling the emergency, and also documenting the results for us all!

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