lml@lancaironline.net Mailing List Archive

In a message dated 3/2/2006 2:27:20 P.M. Central Standard Time, dfs155@adelphia.net writes:

Your post had the following line:

>>>and it is this location of a jack lift point that requires 120 to 150
pounds applied to the tail (tail tie down ring) to lift the nose off the
ground.<<<

I don't often (if ever) disagree with you but let me pass along an "event" I
experienced about 10 - 12 years ago that convinced me to find another way to
hold the tail down than with the removable tie-down ring.

I was doing the "annual" and had jacked up the airplane to change the nose
wheel tire. I used the tie-down ring to hold the tail down (my hangar at the
time had some really heavy-duty steel rings set in the floor to which I
secured the rope). I had just finished re-installing the nose tire
(thankfully!) and was planning to do a gear swing, when the tie-down ring
pulled out of the aircraft and the nose gear dropped to the pavement.

If I hadn't taken a moment to have a pipeful, the failure likely could have
happened while the gear was up. I'm sure that besides the racket of the nose
hitting the ground, the airplane would have come off the jacks, due to the
ensuing angle, with all the attendant additional damage one can imagine.

I could never determine just why the pin pulled out of the socket - it was
examined carefully and no defect could be found. I had taken care to see
that the pin inserted fully and that it did in fact, go in far enough to
insure that the spring loaded balls were slightly past the upper edge of the
socket.

I never figured it out but that was the last time I used the tie-down during
jacking, though I still use it strictly as a parking tie-down point.

Dan,

Interesting because I put about 70 pounds on the tail itself (35 each side on top of cushions) and use the tie down ring attached to heavy weights on the floor to stabilize the airplane against a tail cone support. Lancair actually suggests the strap method - no weights on the tail. I don't like the strap method because it is located too far forward requiring even more weight.

The tie down ring "should" be able to hold 150 pounds, but nothing is a sure thing as you discovered.

Thanks for the note and I am going to pass your warning along thru the LML.

Scott Krueger AKA Grayhawk
Lancair N92EX IO320 SB 89/96
Aurora, IL (KARR)

PS Safety is thinking about what can go wrong and fixing it just before it does go wrong! This is helpful in keeping our hobby horses out of the doll hospital.