engine "failure"
 

Flying a PA 18-150 at full throttle. With absolutely no warning the power cut to idle. Just as if someone had closed the throttle. Was too low (700 ft) to do much checking -changed tanks (both tanks were near full), selected carb heat, made a very brief radio call and landed in a field. Engine was still ticking over when I landed and then I found I had full power available once more. The failure was too sudden and smooth for ice. It was too smooth for vapour lock or fuel starvation. The gascolator was clean. The tank vents were clear. I checked fuel flow it was fine. I stripped the carb -no debris in the filters or in the jets. The trottle cable was sound. The carb floats were a bit out of adjustment but not by much. Any suggestions as to possible cause would be gratefully received.

Well done is the first thing to say and I bet you are glad you did a PFL recently :D

How 'sound' was the throttle cable?

Any chance of it getting caught, stretched, snagged or generally messed around with in any way?

Again, well done for being on the ball.

G:ok:

well done for getting it down and walking away.

Out of interest what was the field like, crop/size etc?

You don't mention mixture?

Last time I had an engine run down like that it turned out that the mixture control had magically pulled itself out. However from 9,500' we had plenty of time to discover the cause and sort it out.

Other than a mechanical defect/anomaly as others have mentioned, my money would be on carb ice anyway. In the right conditions this can manifest itself rather quickly. Do you have any idea on temperature/dewpoint at the time and altitude of your flight?

Oh, and another suggestion: water in the fuel? Any chance of that?

Primer in and locked?
If it had a seperate Primer that is

That would cause a simlar thing

99% sure to have been Carb Ice

First off, congratulations on a very well handled EFATO.

Personally I think a slug of water in the fuel would explain what happened. The engine injested solid water which would have killed it instantaneously so when you thought it was at idle it had actually quit and was windmilling. As the prop windmilled the water got sucked through the engine and when it got gas again it started running at the commanded (idle) power setting by which time you were probably in the short strokes of the PFL

Not so daft Cjboy.

More than one person has been caught out by that.
I know of one large guy winding the trim on a cub did the same thing twice within about 2 mins.

In fact at full throttle 99% sure NOT to have been carb icing (it was an instant cut as well)

I once had an engine failure which was caused by one of the inlet valves sticking open, which presumably screwed up the induction to the other 3 cylinders. In my case the inlet valve remained stuck open and the maintenance guys were able to confirm the cause of failure. Possibly in your case the valve freed itself which may explain why the engine operated normally after your field landing. If this is the cause, if its stuck open once it could stick open again..........

Glad you made it.

I also had an engine failure in a SE with a complete loss of thrust and I was full throttle for over 45 seconds. They assured me it was carb ice but I didn't bought it, I guess they just said it because they didn't found anything.

I fly twins now. After my first seconds during takeoff that I'm a single (meaning closing throttle and going DOWN to land on runway or in front) until I have enough speed, I can just identify, verify and secure and fly away, go back and land on one engine.

I don't feel good in a single engine. Many guys I know crash landed a Single in a field and survived. Many guys I know landed a twin on one engine without declaring an emergency, since it isn't, it's a procedure. Yours may vary but I prefer the latter.

Oh boy, that's really a complete loss of trust! :eek:

If it's any help I once took off with the primer unlocked in a PA28 (ahem). The engine didn't display any particularly noticable symptoms until I got to circuit height when it sounded a bit rough and I had to keep the throttle wide open to maintain height. I completed the circuit and landed. Just as well I was on my own.

Just a reminder but the thread start was

at full throttle With absolutely no warning the power cut to idle.

So that rules out carb icing, , water in the fuel (basic PPL engine knowledge?)

Sticking float valve?

I'd be suspicious of an intermittent fuel line blockage of some kind. Small items can play havoc once inside a line. I've seen a stray tiny disc of metal (5-6mm dia.) that somehow got into a fuel tank, then into the fuel line.
Once in the line, it behaved like a clack valve or throttle butterfly. Under power, it spun around at 90° to the fuel line, and virtually closed off the fuel flow. Once the throttle was eased back to idle, it fell back to a position that was in line with the fuel line, and let a full flow of fuel past.

I also plead guilty to having committed the elbow closing rear throttle.....just after take-off!

slug of water seems highly probably. Any info on power checks procedure? When was tank changed? Any info on the aircraft's previous flight/how long ago/ parked inside or out of hangar? Tank caps info?

Electrical problems / air filter problems. Contaimants/ blockage are possible but seem unlikely.

flyme273

It might be worth checking the condition of the fuel header tanks and their fuel lines. See if there is any gunge/corrosion inside, as well as being a possible water trap. They are fairly accessible, but not often inspected afaiK;

Yes, if this happened to me I would completely strip down the entire fuel system, including an overhaul of the fuel servo, before any further flight. This is not normal (in case that wasn't obvious :) ).