59-06-03 MOONEY: Applies to Models M-20 and M-20A Serial Numbers 1002 Through 1364.
Compliance required as indicated.
A failure of a rudder hinge bearing bracket (P/N 4003) has occurred on a Mooney M- 20A. To preclude the possibility of similar failures occurring on these brackets or on the aileron and elevator hinge bearing brackets, the following inspection and rework is required as indicated:
Within the next five flight hours, inspect the welds which attach the hinge bearing housing (7/8 inch O.D. x .058 inch 4130 steel tube) to the fixed surface hinge bearing channel (P/N 4002). Bearing bracket assemblies (P/N 4003) are installed as aileron, elevator, and rudder hinges. The inspection shall be conducted as follows:
Remove paint from welds and, using a 10-power glass, inspect for cracks or inadequate weld (i.e. weld which does not completely fill fillet cross section area.)
If cracks are found, the bearing brackets on that surface must be removed and a set of modified hinge bearing brackets (P/N 4003) installed prior to further flight.
If inadequate welds are found (i.e., such as but not limited to, not completely, filling in between the face of the outer race and the top of the channel leg and/or inadequate fillet radius between the edge of the outer race and the top of the channel leg) the defective bearing brackets must be removed and a set of modified hinge bearing brackets (P/N 4003) installed on that surface not later than April 15, 1959.
A set of hinge bearing brackets is defined as follows: Aileron --all three (3) hinge bearing brackets; elevator - outer two (2) hinge bearing brackets; rudder - upper two (2) hinge bearing brackets. The installation shall be accomplished as follows:
(1) Install AN 960-3 washers (2) with each new hinge bearing bracket, one at each attach bolt between bracket and structure except at the tip elevator hinge where P/N 8389 shim should be used in place of the inboard washer.
(2) Rudder
(a) Remove fabric covering small "D" shaped cutout in plywood at trailing edge on right-hand side at each of the upper hinges. Do not remove gap tape or lower hinge bolt.
(b) Replace hinge bearing bracket (2) and recover access openings with fabric patch (use Butyrate dope.)
(3) Elevator
(a) Remove fabric covering small "D" shaped cutout in plywood at trailing edge on under side at each of the outboard hinges. Do not remove gap tape or inboard hinge bolt.
(b) Replace hinge bearing bracket (2) (see item (1) for use of ship at tip hinge bracket) and recover access opening with fabric patch (use Butyrate dope).
(4) Aileron
(a) Remove counterbalance weight fairing and two access plates at trailing edge of wing.
(b) Disconnect control tube and remove aileron.
(c) Check clearance between aileron gap strip and existing hinge bearing bracket. If this clearance is not approximately 1/16-inch, the gap strip may have to be dimpled at the hinge to allow clearance for heavier replacement bracket.
(d) Replace hinge bearing bracket (3).
(Mooney Aircraft Inc. Service Letters 20-44 and 20-45 cover this same subject.)