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JUNE
1, 1993
SUBJECT:
RETRACTABLE FLOAT MAIN GEAR MECHANISM - MANDATORY
TO:
ALL Kitfox™ AIRCRAFT OWNERS WHO OPERATE RETRACTABLE FLOATS, 1100 series,
Serial No.s 01L0492 through
44L0493.
FROM:
SKYSTAR AIRCRAFT CORPORATION
It
has come to our attention that it is possible to damage the retraction
mechanism during the rigging of the floats. The problem has only affected the
left float mechanism at this time. Two situations have occurred during the
initial rigging of the floats and to date there have been no failures arising
from flight operations with the floats. This situation arises when the left
float gear retraction cables are set to 30 pounds tension and then the right
float right float gear retraction cables are adjusted next in sequence to 30
pounds tension. If the gear retract cables are rigged such that the left float
gear reaches it’s down and locked position prior to the right float gear
reaching it’s down and locked position, damage to the left float gear
retraction mechanism is likely. The damage can occur when the left float gear
is down and locked, but additional movement of the johnson bar is necessary to
move the right float gear to the down and locked position. This additional
movement of the johnson bar will indeed move the right gear to it’s down and
locked position, but it will also pull the cables attached to the left gear.
The left gear cannot be moved any farther because it is already down and
locked. When this happens, the link tube (part of the retraction mechanism for
the left float gear) is likely to be overstressed. Subsequent operation of the
landing gear retract mechanism will no longer move the left gear fully to
it’s down and locked position.
RECOMMENDATION
All
amphibious float owner/operators must check their gear retraction cable
rigging per the attached instructions to make certain that the cables are
rigged properly, and that the right and left gears reach their down and locked
positions simultaneously. Both the right and the left link tubes (see attached
drawing) must be inspected for evidence of bending or twisting. In addition,
the main gear over center travel must be checked per the attached drawing to
make certain that sufficient over center travel exists. The gear retraction
cable rigging must be checked at 100 hr intervals thereafter to insure that
the cables have not gone out of rig.
1. Support the
floats on blocks.
2. Remove the main
wheel assembly through the center opening in the float.
3. Note: place a
straight edge so it runs from the center of the bottom shock pin holder and
the center of the yoke tube as shown in drawing. Measure the distance from the
straight edge to the center of the top shock pin. If necessary, the stop may
be removed and shortened by grinding to gain sufficient over center movement
Refer to Fig. “A” to determine where to grind. Ensure over center is
1/8” to 3/16”. See Fig. 1.
4. If it is
necessary to replace the left float link tube, then loosen the retraction
cables. It is not necessary to remove cables or their pulleys from their
mounts. Remove the two AN3C 1OA bolts which hold the #5060
link tube. One bolt holds the pulley mount #504 1 and the other attaches
the pin link tube #5042. Remove the parts from each end of the link tube and
save the 0-rings and washers.
5.
Remove the bolt
holding the link tube to the link arm and remove the link tube.
6.
Re-assemble in the reverse order of the above. Ensure that the 0-rings
and retaining washers are greased and in the original position.
7.
See the attached rigging instructions for model 1100 AM Floats.
8. Check the
aircraft per the float installation instructions to be certain that the float
cable tension which holds the gear against the stop is at 30 + - 2 pounds. It
is very important to gradually rig the floats at the same time and to make
certain that the left and right gears operate in unision. Do not force the
retract handle in the down position without monitoring the cable tension. The
handle and lever have enough leverage to twist the linkages.
9. If the link
tube is found to be bent or twisted, then a new reinforced tube is being made
available on an exchange basis for only the shipping and handling costs of
$10.00. An upgraded left gear rotation mount is also available which the
factory has installed on all floats beginning with serial no.
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FRONT
VIEW OF MAIN LANDING GEAR
