Thank you Peter. I actually had to pull over to respond to your message Did you have any failures like mine in a Cherokee? Piper says it is a first. If so I would like to inform TSB as I think a case is building towards an airworthiness directive. If this really isn't the first failure of a Cherokee t-bar control assembly or finding that the weld is cracked, TSB really needs to know this. Please advise, okay? Thanks. Tom
The first failure was a tailwheel attach bracket that was subject to an SB which I missed when the plane was purchased, so I blame myself for that. The second was a failed aileron boost (spade), it had about 400hrs zero rust and the TSB did an investigation. I was disappointed because the mfgr was silent throughout and I found out through an owners forum that it was not an uncommon failure. The most recent was a tail brace tab failure and I found that there had been multiple similar failures in the US but nobody bothered to report it. In each case I reported the failure to the mfgr, I hunted down emails of other owners am forums and posted, but in 15 years of ownership not once have i been alertred to problems by other owners.
I came to the sad conclusion you are on your own and need to proactively check everything that can kill you not just what the inspection manual says. Certainly every weld needs careful visual inspection every year in an older steel tube structure.
Thank you Peter. Glad to hear your 3 failures didn't result in any injuries or tragedies. Hope that is the last of them in journey as a pilot. Based on the feed back on this forum entry, it appears that there are some concerned pilots out there that I believe will pass the word around about this incident. If it saves even one unsuspecting pilot it will be worth the posting and subsequent discussions. Another T-Bar is suppose to be examined today from a Cherokee with 12,000 hours. I advised everyone as soon as I hear about the results. Thanks again for your participation and feedback. I think it is important that we look out for each other in this vocation. Cheers.....Tom
Hi RXL and NEWBIEWIINGS.. Thank you both for your feedback and sharing your thoughts. This is my first exposure to an, "crack" detection methodology. As you can appreciate, as a previous 1963 Beech Musketeer owner and seasoned flight instructor, I am familiar with the need to send fixed props away for inspections. Based on my later photos of the cracked T-Bar I am suspecting that is a die penetrate test, am I right? I have been informed that another T-bar is being checked today. I will keep everyone apprised. As I might have mentioned earlier I believe this is one of those, "out of sight, out of mind" Achillie's heels situations that can rise up and bite you hard which is the motivation for my post. This information REALLY needs to go viral to protect private owners, CFI"s and instructors. TSB will eventually produce it's report, but jurisprudence dictates we step up to the plate and protect each other. Thanks again for your feedback. Cheers!
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Last edited by countryman on Wed Mar 09, 2016 9:25 pm, edited 1 time in total.
A practacal test that pilots of small planes can do as part of a walk around is to fix the control column with a seatbelt (full elevator/aileron) and then apply some reasonable force to the control surfaces ( say 5-10lb) to look for excessive play and the hope that if something is close to giving way it may bend now before it actually brakes. Quick and easy to do.
Yes good idea Peter. Thank you. Actually that was a question that TSB had for me, "Do you secure the control column via the seatbelt?" I said, 'No" because the school Cherokees have control column ties installed.
BTW, "Thank you" PilotDAR for creating the link on PPRUNE. I never thought of that even though I am a member. I so seldom access aviation websites. This is clearly a good way to "get the word out". I had contacted another Canadian general aviation advocacy organization however, to my surprise, dismay and disappointment I was summarily dismissed!
UPDATE I just received word that a third T-Bar control assembly PASSED its NDT inspection. This particular assembly came out of a Cherokee with 13,000 hours. I am not sure how this successful test is going influence the future actions of the TSB and/or Piper Aircraft Corporation however, it does shed a little of positive light on a disturbing situation. Submitted for your information and benefit.
Congratulations on finding another piece that's confirmed to be in good shape.
I'm fairly certain the second set of pictures shows the UV dye penetrant test. As the name suggests, the liquid is applied to the piece being examined and then excess wiped off. A UV light source will show whether any dye has settled into cracks.
Sorry about the mix-up in the hours (21,000 vs 12,000). The fact your replacement T-bar is from a donor with 13K hours adds to the mystery. It would probably be tough to nail it down to something definitive, but I'm thinking it could be a matter of the incorrect rod being used, or a rookie welder. The tube material isn't that thick, and using too much heat would most certainly cause brittleness in the area surrounding the weld. Maybe the TSB or Piper will go all out on this one and order destructive testing that will determine the root cause.
A weld joint in alloy steel will nearly always be surrounded by a "heat affected zone" the result is that a crack at the interface between the edge of a weld and parent material is not uncommon. That is the place to look for cracks, but happily it is nearly always the case that the part on the whole is designed to assure that the weld joint is not the most highly loaded area of the part. This joint is a prime candidate for high cycle fatigue, and very limited opportunity to detect a crack beginning. Obviously crack growth accelerates as the crack grows. At some point, one swift application of force completes the crack.
Some aircraft came with Flight Manuals which provided an approved procedure for landing without elevator control. I know that many Cessna manuals have it, but I do not have any recent Piper manuals to review. I've had a look through the regs, but cannot find the reference on the regulation side. For those with access to a later model Cherokee Flight Manual, it might be worth a look in Section 3 to see if this procedure has been presented. It seems like a recent awareness of this procedure could be timely right now.
Thank you Newbiewings and PilotDAR. Yes it will be interesting to see what TSB has to say about the the material and the weld. I suspect you both have a very good understanding of welding procedures and material integrity. PilotDAR you are absolutely correct that education can be a life saver. I will check various Piper POH's and see if I can find something on emergency approaches with just trim. However, when the top of the t-bar became disconnected, we also lost longidutinal axis control as well as there was no movement in the ailerons.
I have heard previously that a plane might be flown "hands off", using only power, trim, and rudders for control. Just over a month ago, out of idle curiosity, I tried it. I did use the yoke for take-off and landing but spent most of an hour flying without it: to, from, and around in a practice area. I wouldn't want to be forced to land like that but it might be possible. Seems like a weird coincidence to read about this kind of failure so soon after that.
Hi New-PIC. Good for you. Yes, play with your aircraft and, "feel" it. I teach my students to, "get off the control column." Not completely, but as pilots we need to occasionally make notes, study our chart while navigating, turn around and talk to a passenger, etc. The sooner we realize we can keep an aircraft stable through gentle input of the rudder the less reliant we are on our ailerons. Yes, reducing power, "gently" and trimming rearward, "gently" can bring you right to the threshold on approach without the need to constantly pull back on the control column. There is an old adage. "The rougher the air the lighter we are on the control column." Gripping the control column will not keep the aircraft in the air so we might as well lighten our touch on the control column and "feel" the pitch through the finger pads of our "index and big fingers" and the pad of our "thumb". Of course the best place to be when learning anything new in your aircraft is at a safe altitude. I am a huge advocate of using trim all configurations. Have fun and thanks for your contribution. Fly Safe.
Flying a circuit without touching the yoke is one of the great exercises in flying a piston single. It's a lot easier than it sounds. If you have to cheat and use the yoke for the flare, well, at least you know you can get that far.
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DId you hear the one about the jurisprudence fetishist? He got off on a technicality.
Thank you Photofly. Suffice to say there are very few pilots that would endouver to attempt such precision flying. The best time to do it is with a flight instructor. The practice of, "precision" flying is best use of air time any pilot can expend. Glad to see you have made the connect regarding the relationship of power and pitch. Practice Safe and Thanks for your contribution.
(e) By using normal flight and power controls, except as otherwise noted in paragraphs (e)(1) and (e)(2) of this section, it must be possible to establish a zero rate of descent at an attitude suitable for a controlled landing without exceeding the operational and structural limitations of the airplane, as follows:
(1) For single-engine and multiengine airplanes, without the use of the primary longitudinal control system.
It's a requirement that it be possible in the plane, it's not a requirement to publish how, but Cessna does. But, to be clear, it doesn't say that you can do the controlled landing, just you can get to the plane to zero descent there! Worthy of a bit of careful practice, particularly for Cherokee pilots right now!
Very interesting. Thank you PilotDAR for looking that up for us. I am sure it took a bit of digging. It certainly speaks to the use of trim. Irrespective of the manufacture's compliance with the regulations in its design of the aircraft, at a low altitude over a runway even if the aircraft is structurally compliant bad things are going to happen fast if the aircraft is not properly trimmed for landing. It is nice to know that the aircraft can be theorically brought into land with just the use of trim, and I have played with it before. The unknown factor in the equation is when and where the loss of the longtitudinal control system occurs. In our case the aircraft design worked as it should but in another situation there may not be time or altitude enough to set the aircraft up for in straight and level descend with just the use of trim. The appropriate trim in our case stopped our aircraft nose from either dropping forward or ballooning the aircraft. Instructors might want to make sure their student has the aircraft trimmed appropriately in landing. Thanks again PilotDAR.
I have in the past , practiced flying and landing all A/C without 1 control surface operating ( ailerons, elevator, rudder ) This is good to do under controlled conditions !
To be clear: it's straightforward to fly an airplane without touching the elevator control system; but that's entirely different from flying an airplane where the elevators are either absent or jammed.
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DId you hear the one about the jurisprudence fetishist? He got off on a technicality.
I always have my parachute as an option. These kinds of failures are much more common in acro planes. I know a guy whos brand new Extra became joystickless in flight. He took his aluminum knee pad clip board and rolled it up to jam into the hole and make a short joystick.. Guess the adrenalin helped find the strength to roll it up!
Well fellow aviators, it has been 7 months today since the failure of the T-Bar control column in the Cherokee that I was flying. Not a word from Transport Canada or TSB, nor FAA. Think maybe they are hiding something or simply, "don't care"? I know it sounds a little advisarial on my part or at least a little controversial but seriously, not a word indicating any future action? I have heard the odd, "rumour" but nothing substantiated todate. If anyone knows anything else it would be nice to hear.
I'm not surprised. I too was disappointed not just by the manufacturer and the government but more so by mechanics and owners who just repaired problems without advertising them. Everybody is afraid of being sued.
I think you are doing the right thing advertising it here but I'd be inclined to take all the pictures and reports etc, put it up on a website (link to it here and a few other places) with key words that ensure it will be easily found.
Hopefully then people interested in that type aircraft as they learn to fly, or consider purchase will google search and find your page and information. So you will help to get the word out directly instead of relying on the manufacturer and govt agencies etc. Perhaps there is also a Cherokee owners page somewhere. Certainly I get much more useful information from the biplane owners out there than I do from the manufacturer these days.
Great suggestion. Thank You. BTW, I checked my email further and saw a PDF link to FAA. At appears when I logged onto their system and told my story, they took it seriously and are conducting inquiries. I reached out them again today. Hopefully I will hear back from them soon. I will keep everyone updated.
New_PIC wrote:I have heard previously that a plane might be flown "hands off", using only power, trim, and rudders for control. Just over a month ago, out of idle curiosity, I tried it. I did use the yoke for take-off and landing but spent most of an hour flying without it: to, from, and around in a practice area. I wouldn't want to be forced to land like that but it might be possible. Seems like a weird coincidence to read about this kind of failure so soon after that.
Don't they teach this at flight schools? I landed a few times with only trim and power to learn how to do it in case of elevator cable failure.
