Jeff_S Posted January 1, 2017 Report Share Posted January 1, 2017 Had an interesting thing happen on landing rollout yesterday. As we were slowing down the engine just sputtered to a stop. My wife was with me and she hates things like that...but so do I! I applied throttle and a shot of boost pump but it just died with me sitting on the runway. Luckily when I went through my hot start procedure it fired up and I taxied into the FBO, but I noticed that the vernier was very "stiff" and wouldn't make subtle changes, only pretty big ones. Once I got it shut down I had time to fiddle with it, and it seemed that the vernier control was not working correctly, e.g. it was not screwing the throttle open and closed. The depression cap on the end seemed stuck so I futzed with it some more and it actually popped off and I saw the spring underneath it. I pushed it back on, then held the cap down and pulled the throttle back and forth a few times and then it "freed up" and seemed to be working normally again. In retrospect, I believe what happened is that in descent I screwed the vernier out so far to reduce power that it got stuck in a closed position and that's why when I tried to add some throttle on rollout nothing happened. Has anyone ever experienced something similar? I'm going to have it checked out before I fly again (would be bad mojo to have that happen in flight!) but would appreciate any else's input. Thanks! Quote Link to comment Share on other sites More sharing options...
takair Posted January 1, 2017 Report Share Posted January 1, 2017 Jeff have not had it happen, but it does seem odd. The push-button releases a ball that rides in what are essentially threads. With the button in, the ball can fall in a recess and thus not engage the thread. I suppose you may have somehow unscrewed it far enough that the mechanism became jammed. I would have your mechanic pull the cowl to ensure the jam is not on that end. I never did get used to the vernier throttle that are mainly on bonanzas. As you realized, this would be a bad thing on a go around. Quote Link to comment Share on other sites More sharing options...
jlunseth Posted January 1, 2017 Report Share Posted January 1, 2017 We had two instructors here at Flying Cloud in Minneapolis who had to do a forced off field in the winter because the throttle stuck on the Mooney they were flying. It was a J. Chief pilot was checking out one of the instructors in the school's rental Mooney. They were doing some maneuvers when the throttle stuck at a low power setting so they have to put it down. The failure was in the control cable. So no, don't go up again until you get that checked out. Everyone was ok and the plane was also, they made a nice landing in a farmer's field. Quote Link to comment Share on other sites More sharing options...
carusoam Posted January 1, 2017 Report Share Posted January 1, 2017 Check the age of the cables...? My prop cable had to be replaced due to some age related issue. (At time of engine OH) Might they be the same? Sounds like something hiding in there that needs to be found out what it is. Thanks for reporting your findings. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
Rodney Cobb Posted January 3, 2017 Report Share Posted January 3, 2017 The throttle in my Ovation wasn't feeling right. It ended up in my hand after landing. Sometimes timing is everything! 2 Quote Link to comment Share on other sites More sharing options...
carusoam Posted January 3, 2017 Report Share Posted January 3, 2017 Congrats on your first post Rodney. Do you have any additional details about your throttle control? What year did it come from, how many hours did it have? That kind of thing. What actually broke? The throttle control is an uncomfortable single point of failure that can have disastrous results. Thanks for sharing your photo. Best regards, -a- Quote Link to comment Share on other sites More sharing options...
aggiepilot04 Posted January 3, 2017 Report Share Posted January 3, 2017 (edited) On 1/1/2017 at 8:01 AM, takair said: As you realized, this would be a bad thing on a go around. This exact thing happened to me last week, and it was not a fun experience. METAR showed gusts to 19G27 and 30 degrees off of the runway heading, but turned out to be gusting to 34 and 50 degrees off of the runway heading when we arrived (according to AWOS). I made the questionable decision to go down and feel it out, staying fast and expecting to go around and elsewhere if necessary. After fighting the airplane down to ground effect, things calmed long enough for me to pull the power back to idle. That's when I got one of those 34 knot gusts. I attempted to push the button and add power, but the button would not release for what felt like an eternity. I'm not sure how long it was, but it was long enough for me to get a few expletives out and to bleed off enough airspeed for the stall warning to start sounding. I continued fighting the gusts in ground effect, and the throttle did finally release (with lots of adrenalin-fed force), fortunately. The vernier throttle is relatively new to me, but I probably should have known to twist in a couple of times and then try pushing again. Edited January 3, 2017 by aggiepilot04 Quote Link to comment Share on other sites More sharing options...
Bennett Posted January 3, 2017 Report Share Posted January 3, 2017 My two cents: Get rid of vernier throttles. They are great for mixture control and prop RPM, where fine tuning is valuable and makes sense, but in cruise flight many of us run WOT, and in other regimes such as go arounds and minor power adjustments in landing, pushing in a button just adds unnecessary complexity. In another thread I recounted how I had a vernier throttle come apart during takeoff, leaving me with no throttle control (full power). A throttle push/pull with a friction adjustment is simple, fast to adjust, and less likely (in my opinion) to jam or break. Sent from my iPhone using Tapatalk 1 Quote Link to comment Share on other sites More sharing options...
Rodney Cobb Posted January 3, 2017 Report Share Posted January 3, 2017 Here's the real head scratcher..............the new cable did the same thing before they were completely done with the installation! It was a 2000 Oviation with around 400TT on it. I agree with Bennett. I'd be happy with a non-vernier control for the throttle. If you look at the very top of the throttle control in the picture you can see the cable that twisted off. Not sure why that happened but it would appear it just twisted off from screwing it in and out with the vernier feature. Don't know enough about the mechanics of how a vernier throttle works to diagnosis the failure but it obviously wasn't working as designed. 1 Quote Link to comment Share on other sites More sharing options...
Jeff_S Posted January 4, 2017 Author Report Share Posted January 4, 2017 I wonder, is the vernier control part of the type certificate for the Ovation? I ask that knowing TCs don't usually get to that level of detail, but questioning whether it would even be allowable to switch it out. Of course, my J didn't have one and I controlled it just fine...gets me thinking anyway. As my situation currently stands, I had a shop pull the top cowling and check out all the cables and linkages and everything is fine. We pushed and twisted and otherwise abused the throttle control and could never get it to malfunction again. It was pouring outside though so I haven't flight tested it yet...but perhaps this was just pilot error and my brain dead act of twisting the throttle past the "stop" in an ill-advised attempt to lose speed. I have to admit I was at the end of one of those flights where my CPU clock speed seemed slow. You know how it is sometimes...slow to retract the gear, accidentally adjusting prop instead of mixture when trying to lean, forgetting that speed brakes have a purpose, etc. Sometimes I'm amazed at how well the engineers have thought ahead of our wet-ware pilot foibles...our planes keep flying despite their operator screw ups. Thank God for that! Quote Link to comment Share on other sites More sharing options...
carusoam Posted January 4, 2017 Report Share Posted January 4, 2017 Rodney, thanks for sharing the details. Jeff, your explanation is elegant. Thanks, I don't feel so alone. Best regards, -a- 1 Quote Link to comment Share on other sites More sharing options...
LANCECASPER Posted January 4, 2017 Report Share Posted January 4, 2017 On 1/1/2017 at 6:32 AM, Jeff_S said: Had an interesting thing happen on landing rollout yesterday. As we were slowing down the engine just sputtered to a stop. My wife was with me and she hates things like that...but so do I! I applied throttle and a shot of boost pump but it just died with me sitting on the runway. Luckily when I went through my hot start procedure it fired up and I taxied into the FBO, but I noticed that the vernier was very "stiff" and wouldn't make subtle changes, only pretty big ones. Once I got it shut down I had time to fiddle with it, and it seemed that the vernier control was not working correctly, e.g. it was not screwing the throttle open and closed. The depression cap on the end seemed stuck so I futzed with it some more and it actually popped off and I saw the spring underneath it. I pushed it back on, then held the cap down and pulled the throttle back and forth a few times and then it "freed up" and seemed to be working normally again. In retrospect, I believe what happened is that in descent I screwed the vernier out so far to reduce power that it got stuck in a closed position and that's why when I tried to add some throttle on rollout nothing happened. Has anyone ever experienced something similar? I'm going to have it checked out before I fly again (would be bad mojo to have that happen in flight!) but would appreciate any else's input. Thanks! On the Ovation I had it died twice after landing at real low idle. It never ran smoothly on the ground even though I leaned aggressively. I changed out the Champions for Tempest and all of that was solved. It would run smoothy and had no problems running at low rpm. Quote Link to comment Share on other sites More sharing options...
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