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'Sled,
The mechanic who told you it's not uncommon for propellers to fail to feather wasn't apparently all that knowledgable, or perhaps he was just a very dangerous mechanic. If the prop wont' feather, the airplane should not be launched. It should be a grounding item, and failure to feather should be a very uncommon occurence.
In older times, we used feather pumps to drive the props into feather. What could occur in that case was that the prop would cycle through feather and right back out again. The secret in that case was to hold the feather button down, which kept the pump running and eventually it would drive back into the feather position. The problem with that was that if the oil was gone, such as was often the case, then the feather button did very little but draw amperage.
When a piston engine with a manually controled propeller is moved to the feather position, it's physically moving the pilot valve and dumping oil pressure to the prop, as well as moving the high pitch stops. The prop should be driven into feather. Depending on which propeller you had installed, spring pressure and/or nitrogen pressure should have driven the prop to feather. The fact that it didn't could have meant one of several things, but most likely the propeller needed servicing, adjustment was required on the governor or prop control linkage, or the governor itself was sludged up.
In any event, if the engine can't be feathered before the flight, then the flight shouldn't launch.
I warned off a check airman once about pulling the engine too low. I told him that if he did, I'd consider it a failure and treat it accordingly. I also told him that if we weren't right by the airport, he'd probably be making a forced landing. Toward the end of the checkride, he pulled an engine, low. When he saw what he wanted to see, he told me to restore power. I told him no, the engine was failed. He pushed and pushed, and I finally reminded him that he made the decision to shut it down, and he was going to have to live with that. He didn't take long to start sniveling and whining about being nervous, and then scared. I finally did restore the power and flew home, and to the best of my knowledge, he's never tried that little stunt again.
I passed, incidentally...though he certainly didn't.
The mechanic who told you it's not uncommon for propellers to fail to feather wasn't apparently all that knowledgable, or perhaps he was just a very dangerous mechanic. If the prop wont' feather, the airplane should not be launched. It should be a grounding item, and failure to feather should be a very uncommon occurence.
In older times, we used feather pumps to drive the props into feather. What could occur in that case was that the prop would cycle through feather and right back out again. The secret in that case was to hold the feather button down, which kept the pump running and eventually it would drive back into the feather position. The problem with that was that if the oil was gone, such as was often the case, then the feather button did very little but draw amperage.
When a piston engine with a manually controled propeller is moved to the feather position, it's physically moving the pilot valve and dumping oil pressure to the prop, as well as moving the high pitch stops. The prop should be driven into feather. Depending on which propeller you had installed, spring pressure and/or nitrogen pressure should have driven the prop to feather. The fact that it didn't could have meant one of several things, but most likely the propeller needed servicing, adjustment was required on the governor or prop control linkage, or the governor itself was sludged up.
In any event, if the engine can't be feathered before the flight, then the flight shouldn't launch.
I warned off a check airman once about pulling the engine too low. I told him that if he did, I'd consider it a failure and treat it accordingly. I also told him that if we weren't right by the airport, he'd probably be making a forced landing. Toward the end of the checkride, he pulled an engine, low. When he saw what he wanted to see, he told me to restore power. I told him no, the engine was failed. He pushed and pushed, and I finally reminded him that he made the decision to shut it down, and he was going to have to live with that. He didn't take long to start sniveling and whining about being nervous, and then scared. I finally did restore the power and flew home, and to the best of my knowledge, he's never tried that little stunt again.
I passed, incidentally...though he certainly didn't.
Lead Sled
Sitt'n on the throne...
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- 2,066
Avbug, you've spent time in northern Utah so you probably know the guy - he's a good mechanic. I should have been a bit more specific. He did mention exactly what you had mentioned - in each of our cases it was a rigging problem. What I gathered from talking with him was that is wan't enough to pull the prop into feather and wait for the RPM to drop off - a prop can do that and still not actually go all the way into feather.avbug said:
Oh well, now you know one of the reasons for my personal motto - "Propellors are for boats."
'Sled
A new chief pilot was getting a type ride in a SAAB 340 at 3 am (is there any other time to do a type ride in the airplane) The check airman decides to "fail" an engine on down wind so he slams the throttle to idle. Back then there were no gates like in the King Airs for the throttle stop and SAAB just had a small spring pushing up a small ball to stop the throttle from going into reverse. Well the check airman had pushed the throttle into almost full reverse on one engine (did I mention that they were at 1500 feet AGL) the aircraft rolled inverted. The new chief pilot froze, the FAA Inspector in the jump seat was not happy, and the check airman quickly shut down the engine and feathered the prop and rolled the aircraft up right very near the ground. The type ride was stoped for the night and the company went to using a simulator for future type rides. True story.
Got to love multi engine checkrides in the airplane....
JAFI
Got to love multi engine checkrides in the airplane....
JAFI
'Sled,
I probably do know him, or at least of him, though there are a few wrenches up in that area that a lot of folks use, that really ought to be in the lockup. I know one that's killed several folks so far, and seems to be free to do it again, and again, and again...
It should be enough to pull the propeller lever to the feather position. Nothing more should be needed. If one is carrying a lot of power at the time it may be a little hard on the prop, but it should still feather. If one has retarded the throttle to idle and then feathers, the prop should always go into feather.
If it doesn't, it's a mechanical problem. The propeller should never fail to feather. I have seen them do this, but more often, fail to come back out of feather. That's where a feathering accumulator pays off, and makes a big difference. I've had the same problem on radial engine aircraft, turboprops, and horizontally opposed piston airplanes.
I dunno about props are for boats; they do offer a number of advantages that a jet doesn't have, including the ability to pull a turbopropto idle and enjoy the braking action in flight, and a few are darn near as fast as or faster than a turbojet (such as the Piaggio Avanti). A nick in a prop is a whole lot easier and less expensive to address than a nick, chip, or crack in a compressor or power turbine blade. An added benifit is that when a lineman goes up a turbojet intake, all one gets are surges and bangs from a compressor stall. That could be anything going on...but when a lineman gets stuck in your propeller arc, there's no doubt as to the cause. And as an added benifit, it's self-clearing, and if you carry enough power, darn near self cleaning, too.
Let's see a cuisinart do that!
I probably do know him, or at least of him, though there are a few wrenches up in that area that a lot of folks use, that really ought to be in the lockup. I know one that's killed several folks so far, and seems to be free to do it again, and again, and again...
It should be enough to pull the propeller lever to the feather position. Nothing more should be needed. If one is carrying a lot of power at the time it may be a little hard on the prop, but it should still feather. If one has retarded the throttle to idle and then feathers, the prop should always go into feather.
If it doesn't, it's a mechanical problem. The propeller should never fail to feather. I have seen them do this, but more often, fail to come back out of feather. That's where a feathering accumulator pays off, and makes a big difference. I've had the same problem on radial engine aircraft, turboprops, and horizontally opposed piston airplanes.
I dunno about props are for boats; they do offer a number of advantages that a jet doesn't have, including the ability to pull a turbopropto idle and enjoy the braking action in flight, and a few are darn near as fast as or faster than a turbojet (such as the Piaggio Avanti). A nick in a prop is a whole lot easier and less expensive to address than a nick, chip, or crack in a compressor or power turbine blade. An added benifit is that when a lineman goes up a turbojet intake, all one gets are surges and bangs from a compressor stall. That could be anything going on...but when a lineman gets stuck in your propeller arc, there's no doubt as to the cause. And as an added benifit, it's self-clearing, and if you carry enough power, darn near self cleaning, too.
Let's see a cuisinart do that!
The Seneca I is similar in cockpit/panel layout and appearance to the PA-28R-200 (Piper Arrow) of its day. If you have any time in the Arrow (I was instructing in the Arrow when I 1st flew the Seneca) you'll see what I mean. It's a good multi trainer. As with all light twins, not much single engine performance. For thrills, read up (if you haven't already) on what is and isn't required of light twins, performance-wise, when an engine fails. Even at well under gross, you'll notice the difference in SE performance (i.e., ROC) on cold days vs. hot days, if you have occasion to do SE work in the airplane in winter and in summer. It is possible to demo the difference between published Vyse/blue line, which is a gross weight speed, and Vyse for a given weight, if you will. I recall my ATP examiner (did Commercial multi add-on in Seneca I, and also did initial ATP in Seneca I) demo'd how the lighter than gross weight airplane climbed faster SE at several knots below blue line, and SE performance wasn't too bad on that cold day at that lower speed. Now, that was with zero thrust, rather than fully feathered, if I remember correctly, so that's a factor, too. But still instructional on weight to Vyse relationship. Could go on, but enough of that. It's a good training airplane. The later turbocharged and higher horsepower (220 hp ? starting with III, I think; II is 200hp turbocharged) versions are decent transportation machines for unpressurized piston twins. Oh, I bought a standard POH and studied it before I took the course; I think the course provider sent it to me. One bit of trivia: I think it has a max landing weight of 4,000, vs. max takeoff weight of 4,200 lbs, for the standard airplane. Check me on that. Good question for oral.
dmspilot00
Independent
- Joined
- Feb 22, 2002
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- 712
dmspilot00 said:
It's a possibility...nothing's set in stone right now...it's still possible to get it done out here if I do it as a pt 61 add on (proficiency) rather than the 10 hour part 141 add-on. Either way, I'm out of here Thursday evening at the latest (looks like Wednesday evening).
Did the CPL part 141. It's a shortened program out here. The syllabus is only 70 training hours and they sign you off...sort of So...if you did it all out here, you could be a commercial pilot at 146 hours [38pvt + 38ira + 70cse on their syllabi(sp?)].
It's pretty cool that you could be a -II at 161 and CFI at 165 if you bust your balls and they can get you through. Toss in the CMEL at 10 hours and you're done at 175...unless you add the MEI...then it's 190 (still not too bad)...the hard part is getting them to fly you.
-mini
dmspilot00
Independent
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- 712
) after about an hour or an hour and a half of talking about trivial stuff...
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