Causes of Forced Landings

[szicree]

Mine was a low oil pressure indication that prompted a precautionary landing in not great terrain. There was something in the oil tank that blocked the pick up tube.

Forgive my lack of familiarity about the Rotax, but does the oil pickup have a screen? Did you ever figure out exactly what caused the clog? Thanks for the info.

[HighWing]

Yes, there is a screen between the return line and the pick-up. Never really found out what it was for sure. It was black and hard when cold, but we took off with a high temp inversion lever and oil temps were high which melted it into a blob that stuck in the pick up - the most likely idea was one of the rings that safeties the cap on an oil bottle.

[SkyPirate]

there's 3 things I do when I first fly a plane I built or bought ,..first I do a power on stall ,..then I do a power off stall ,..then I do a dead stick landing,..of course I'll get my position right first ,..headed for the runway , I try to do this on a day with relatively low cross winds ,..
and just about every day that I fly I'd do one of the 3 mentioned do's...
so I guess one would have to call that a self induced forced landing ,..but it's a good thing to practice,..because you never know when you will have to do one without a choice.

Chase

[rogerh12]

Howdy all;

I actually had two forced landing, both in my Zenith 601 HDS running a VW conversion engine. The first one occurred when the new wood propeller broke off in flight, at about 6K feed AGL. I made it to about 1 mile from the airport, and landed in a soy bean field without event (thanks to the drought that year in Kansas). Turns out the new prop I installed threw the leading edge off again, it had a urethane leading edge which had come off once before. This time, it disrupted the airflow and sent the prop into a harmonic vibration for about 20-30 seconds, then BANG !!!. I suppose if I had more than 60 hours in my log book, I might have understood what was happening and throttled back, but I didn’t. Actually, when it broke one blade off, it was quickly followed by the other blade and the front of the crank. What with all the oil & sh@t flying up in the air, the first thing that went through my head was, crap, I just got hit by a flack burst. (perhaps I had been flying that combat flight simulator too much)…

The second time I was at 4K Agl and the intake valve roller popped off the valve face on one cylinder. With the engine now pulling a vacuum on one cylinder, is shook the plane awful bad, in fact I thought I lost part of the prop again, but landed at the airport at reduced power, with altitude to spare… Remember, altitude is insurance, I recommend everyone fly with a policy and always be thinking: what would I do if the engine quit right NOW?

[SkyPirate]

Roger ,.we (our EAA group) are building a 601 at TBN ,.I'd like to hear about your flight experiences in the 601 ,..pro's and con's on it's agility etc.
chase001@centurytel.net

thanks

Chase

[szicree]

the intake valve roller popped off the valve face on one cylinder.

I'm afraid I don't understand what this means. Can you elaborate and state the type of engine? Thanks.

[SkyPirate]

I'm afraid I don't understand what this means. Can you elaborate and state the type of engine? Thanks.

sounds to me like the roller rocker stud bolt failed or rocker assembly,.. and it left the valve closed,..which is worse then just having a fouled plug,.. because the intake valve being closed all the time will create a vacuum in the cylinder because no fuel is getting in the cylinder to be ignited,..just a wild guess

Chase

[rogerh12]

It's a VW conversion. The VW uses push rods to actuate the valves via a rocker arm. The end of the rocker arm touches the valve stem face via a screw adjustable roller ball, to reduce friction I guess.
The roller ball just broke off. They called it a freak failure.....
Roger

[SkyPirate]

that is odd roger ,..I've seen rocker studs break ,..posh rods get bent , or stuck into the valve cover..even valves get bent ,..never seen the ball on the rod break off,..

Chase

[szicree]

Got it. I know exactly the ones you mean, had em on an old notchback back in my teens. When you said valve face I took that to mean the actual face (the part that meets the valve seat). Thanks for the info. All of this info will help prevent others from having the same trouble.