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That uneasy feeling ????

C

[email protected]

Well Known Member
Look, Look, and Look again. Took the RV6A up for a flight yesterday, as I was doing a walk around I checked the ailerons for proper movement. Every thing seemed alright but I had this uneasy feeling when checking the right aileron. I notice a very small amount of play in the linkage, not enough to cause problems just a hint. I checked the left and it had no play. After debating for a few minutes whether or not to pull the inspection plate I decided I better and dug up a Philips to remove the screws. Boy am I glad I did!!! Laying on my back it took a few seconds to see what was wrong, the nut on the bell crank pivot bolt had loosened and was now on the last 2 -3 threads and the bolt had worked up and almost out of the lower hole. Apparently I had missed putting a cotter pin in this bolt. Well I immediately open all the other inspection plates to check all the other bolts for cotter pins. All others where in place.

I had 5 EAA members, 2 EAA Tech advisers, an engineering friend, an FAA maintenance person from my local FSDO and a DAR check over the plane before first flight and no one spotted this.

I?m not blaming anyone, just saying the builder has the full responsibility to check everything. If you have any uneasy feelings before you fly CHECK IT OUT. I?m not proud about this but very happy to be alive to tell about it. It can happen to anyone.

RV6A ? 7.5 hrs phase I
 
Good Caution!

John,

Thanks for sharing, that is indeed cause for a "scarey" thought. At least you did make the decision to "stop and check it out". Expecially during Phase 1, I only hope that I focus on caution when I get there. Glad you did!
 
Trust your gut...

[email protected] said:
Every thing seemed alright but I had this uneasy feeling when checking the right aileron.
Click to expand...
You've gotta trust these feelings. Good thing you did. It would have been challenging flying with only one aileron - doable, but scary. I think these should be nylocs.
 
That Uneasy Feeling

Yes they called for nylocs but in my infinte wisdom I put castle nuts and cotter pins anywhere I could not inspect during a walk around thinking they would provide a more positive lock. (If you put the cotter pin in)

John
 
Great Story John!

The best part about it is that even though you were planning to fly - you stopped and tracked down the problem instead. That shows great discipline!

I remember when I had about ten hours on the -8, and was preflighting for another test on a beautiful day. When I grabbed the horizontal stab near the root, I heard this very, very tiny "click". Gee, did that thing move? I don't think so...but again, just this hardly audible "click"...Nah, there's no movement, but again..."click"...

So I took off the parchute and flight suit, got out the screwdrivers, put the tail up on the stand, and pulled the empennage fairing. That took awhile - I hate screws! Wiggled the Stab - no click. Checked the torque on the spar bolts - everything was perfect. The click"? Must have been a minute motion between the fairing and the aluminum. Put everything back togetehr, and no more click...but I'd lost the daylight!

But boy, was I glad I had checked. What if it HAD been something, and I ignored it? I was going out for spin testing....instead, I went home, hada beer, and called it a victory - for discipline!

There is no test that can't be put off until another day....

Paul
 
If in doubt, don't.

I have learned to listen to the hairs on the back of my neck. I don't look at chicken entrails, and I trained as an engineer and have 3500hrs military flying before the RV. However, every time I have suspected something was not quite right, and pushed on (and survived) subsequently there was shown to be an anomaly with the aircraft. Two instances were flying the C130E with a crew. Once was a fueling cock up where we couldn't get the book performance and later found we had too much fuel on (U/S fuel gauges contributed). Another was similar, not expected performance, but due to bleed air leak. Both times there was definite uneasiness but unfortunately not conviction, the performance deficit was small enough to convince yourself it was 'normal'. My RV experience was during the test phase. Mud daubers were giving me grief so I used -4 AN caps to close the fuel vents on the fuse bottom of my RV-4. Sure enough next time I went to fly I rushed, due to fading light and push to rectify other problems. Luckily one of the 'other' problems meant the engine wouldn't start and I finally gave it away for the day. When putting in the bungs I saw the vent caps.... As the saying goes, never trade luck for skill. Listen to the hairs on the back of your neck, they may save it.
 
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I had a similar problem with the flaps on my RV-8

The builder (not me) had trouble getting the proper nut on the lower end of the flap actuator tube (the thingy that actually goes down to the trailing edge of the flap through the skin of the plane). He used an improper nut and after about 180 hours it worked its way off on one side.

One day I went out to fly and noticed that when I raised the flaps there was the slightest hitch in the movement. It took me a while to find the problem but I finally did find it.

I fixed it and now check those connections on each pre-flight.

BTW, the Van's folks say that the RV-8 has been tested to see if it has enough aileron authority to overcome a split flap condtion (it does).

bruce
N297NW
 
A while back I was doing an inspection on a GlasairIII I had bought .[I wasnt the builder]. I had already flown 100 hours or so at the time of the inspection.
I found NO NUT on the elevator push/pull tube fitting. I had been flying not knowing the bolt could fall out at any moment. [luckily it didnt]
I decided to sell the aircraft and stop flying.
This didnt last long though and I decided to build a plane.I am now only prepared to fly something I have built. Except a airliner of course.

I also remember a AMO telling me they found the wing strut on a 172 missing a nut and only held by the bolt.

Hair raising stuff!!!!!!
 
In my Instructor days, I remember two Northrup T-38s lost to an aileron disconnect. The flight controls were completely hydraulic and when the push pull rod became disconnected (cotter pin left out of castellated nut) the aileron could move where ever the actuator control lever vibrated to. The accident reported recommended a fiber / castle nut that did not exist. IMHO, a simple nylocs nut would have saved those aircraft.

My first homebuilt was a Pitts S1S, and like you it was inspected by several people. All of us missed the standard hardware bolts and nuts holding the bearing caps that hold the stick assembly in place. I had intended to replace those cheap hardware bolts with the proper AN hardware but had simply missed it. Several hours of flight later I noticed the stick assembly lose and I could raise and lower the stick a couple of inches. I flew an emergency pattern holding up pressure on that Pitts sensitive stick to hold the stick into the upper bearings. The landing came out fine.

I pulled every panel and checked every bolt in the airframe. Gee... the only problem I found was in the control system.. Good grief, How did I miss that?
 
And if you think it only happens to us weekend fliers...

- Time and Date: 2000Z on 22 Sep
- Aircraft: T-38A, TN 65-0442, 394 TS
- Details:

-- The aircraft was preparing to launch for Whiteman AFB, MO.

-- As the dual crew taxied out, they heard a loud pop followed by abnormal readings on their number one (left) engine

-- The crew secured the aircraft and had it towed and hangared at a local Fixed Base Operator (FBO)

-- Upon inspection of the number one inlet, it was determined that the engine had ingested the aircraft forms

-- Previous similar incident costs have ranged from negligible to max of $150,000


bruce
N297NW
 
Inspection Plates

I used the AL inspection plate covers as a template to make 3 new plates out of LEXAN. One under each wing at the bellcrank, and one at the elevator pushrod attach point under the horo stab. Every preflight can then include a visual check to make sure those nuts, cotter pins etc are exactly where they should be.
 
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