landing gear lesson learned

R

Rodney

New member
I was working some landing practice, and in doing so decided to exercise the gear system a bit. I cycled the gear several times while doing a few landings instead of just leaving them down. After landing, I noticed a tiny hydraulic leak at a pressure connection in the wheel well next to where the strut raises up and rests. It was at the end of a length of metal tubing that had a flared end and a screw on connector, like for water tubing on the back of a fridge. Anyway, I decided that however small I didn't like it and decided to re-flare the tube and re-connect. All went fine with that, leak went away. However, in doing so I inadvertantly shortened the length of tubing just enough, to pull it away from the wall just enough, to, well, I'll get to that....

On the next flight I raised the gear and all was normal. After a moment I noticed that the visual gear position tabs on the wings were indicating that the gear had come back down, and my gear up light had gone out. Attempts to raise them normally were unsuccessful, and I was indicating zero hyd pressure while doing so. The hand pump showed no pressure as well. I was flying around at 100mph or so. I could not get the gear lights to indicate down, nor could I get the tabs to indicate down and locked, only that the gear was down to some extent.

I decided to slow to flap speed, and while doing so the down and locked lights came on and the visual tabs confirmed down and locked. Landed flaps up without incident.

To shorten this tale, it turns out that the metal hyd tube was off the wheel well wall just enough for a bolt/nut on the strut to catch and sever it thus allowing hyd fluid to empty out. I replaced the line and securely attached it to the side of the well clear of the gear assembly. Inspection of the other side is secure as well. System has operated normally since.

I discovered that without hyd pressure the gear will auto lower and the aircraft must then be slow enough for the strut springs to lock the gear down. I'd like to find further info on those springs - specifications, replacement, maximum size, etc... It was rather uncomfortable until I got slow enough (less airstream blowback) to allow the strut springs to force the struts forward enough to indicate down and locked.

I'm interested for your comments and experience with this system.
 
Rodney:

What you discovered was the design to lower gear in the event of hydraulic pressure loss. Letting the gear drop is the final of three gear lowering methods. The intermediate one is the hand pump should the power pack or pump fail and you still have fluid. I was less fortunate with my landing gear adventure. The hydraulic system locked. Thus the power pack was nixed, the hand pump was useless and the gear could not drop. The only option, after a long time trying stuff, was a gear up landing. Fortunately I was insured.

Plane and Pilot editor, Bill Cox, owned two different 14-19s at various times. One gear leg snagged on something (I forget the full story) when he sprung a hydraulic leak and that one leg did not fall as it should....nasty.

In short, yes, it's unfortunate, but you were fortunate to have a good outcome.

You can still get the springs from Bellanca. Some people delay the inevitable by sticking washers in the bottom of the legs.

Jonathan
 
About 25 years ago or so, I jacked up 515A (14-19) and we used a bathroom scale to figure out how much pressure the springs exerted ( I think we aimed for 60 pounds because that's what some other plane required) We inserted a bolt into the end of each spring so the head of the bolt was a spacer and the threaded portion went into the spring to keep it all secure in position. Next annual was done by a relative stranger (getting it ready for sale) and unbeknownst to me the mechanic noted the bolts and thought that was kind of Mickey Mouse, so he fabricated new spacers out of Aluminum-the problem was he made the spacers the length of the entire bolt rather than just the head. Out of the annual the plane came and I took the potential buyer for a ride. The gear would not fully retract!!! We landed, and after a discussion with the mechanic and some quick repairs, we got it to work just fine. I have since then maintained that anytime you do anything to the gear, you should swing the gear (on jack stands) prior to flight. As an aside, I was hoping that at your next annual, when you have the plane on jack stands, you could take a bathroom scale and let us know how much pressure those little springs exert. We know yours will extend the gear at airspeed, and the rest of us could use that as a guide to check our springs. Or better yet, does anyone know what the correct strength should be???(PS--I sold the plane and got to see it again at Columbia this year)
 
Ahh, I don't mind if we wander here and there.

Good idea on me trying to get the tension measurement of my springs, since I did just op-test them good. If I'm not mistaken, they were purchased from Bellanca when the assemblies were re-built around 5 years ago. It was below 80mph or so when the gear finally indicated down and locked.
 
Of course I missed my 515A-just felt I had to have a "safe" spam can (bonanza) to transport my kids but now I'm back in a cardboard constellation and loving it (went up today-gorgeous)
 
Indeed, Larry, they do indeed keep falling. In both cases you cannot blame these sort of fatal accidents on the aircraft. Cirrus and especially the Columbia have spar strength that make older style aluminum spar structures seem like soda straws. The only thing comparable is those twin Sitka spruce spars in our Bellancas, except ours can flex more gracefully.

Although most of us have figured this out long ago, many of these well heeled people work high pressure jobs with inflexible missions that displace flight training time and regular life. This simply is not consistent with GA.

In GA you *cannot* take off with any absolute certainty that you will arrive at your chosen destination. There are no individuals you can threaten, push, and manipulate when failure looms.

These man who have never in their lives have been affected or deterred by that confluence of physics, meteorology, and chance that rule the empire of the air so easily become frustrated and lost. You cannot reprimand, sue, or fire God, nor can you influence him with a bad performance review.

Thus, the very source of the affluence that put these most unprepared of pilots into expensive, fast, advanced aircraft, ensured that their cockpits would become their coffins.

Those of us who witnessed that little boy saluting the caisson bearing his assassinated father who was our President still ache because that boy's life this should not have ended the way it did.

Sorry to break a jocular mood, but this is a scenario too often played. It bothers me.

Jonathan
 
I am an ER Doctor and have a theory as to why Doctor's crash. Doctors take chances with patient's lives every day and no matter what happens, the Doctor is never the one to die. As a result it is easy to be lulled into taking chances with our own lives-unfortunately in airplane situations, we are the ones to die.
 
Perhaps JB, but the tails do part company with certain well known airplanes.

As regards to those who allow high pressure jobs with inflexible missions to displace flight training time and regular life, are those the same ones that believe they can threaten, push, and manipulate their way through life, and actually do believe they are good enough to pull anything off? Perhaps they truly do think they can manipulate any situation. As some of us have realized thats not possible. Darwin at work?

There are no guarantees anywhere in life, GA certainly is no different. Someone once said that aviation is not inherently dangerous, but to a greater extent than the sea, it is terribly unforgiving.

I have waited for weather on many occasions. Damned inconvenient. Every man and every machine has it's limitations. Exceed them and risk whatever fate comes your way. I choose not to exceed mine, because I am not that good. I dont think I can bully the world to do what I tell it to. It is that mindset that kills these guys. Not GA, not airplanes. Well maybe airplanes, because the damned things shed their parachute safety devices if deployed at 200 knots.

We are probably saying the same thing here. But I am so tired of no one taking responsibility for their actions. Why must we always find someone, something else at fault? Why cant we accept that if I choose to fly through thunderstorms, ice, or any other situation that is beyond my capability that something bad may happen? And when it does why must someone else be to blame?

Wow. Where did that soap box come from?
 
You, Peter, and I are vigorously agreeing, though none of the three posts is redundant. Each futher illuminates the others.

Hey, we can get serious every now and again, eh?
 
Wow, This is great! Discussion, phylosophy, debate---and all I hoped to do was learn about landing gear...... :)
 
The downlock springs are available from the factory, I received two a couple of months back, I have not installed them yet, one had more coils per inch than the other, the factory assured me that they have the same tension even though they have a different amount of coils per inch.

I believe that the manual for a 14-19 says that the gear should come down at around 80mph without any hydraulic pressure.

dan
 
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