Applies to All Models 415-C, -CD, -D, E, G and F-1 Aircraft.
Compliance required at every 100 hours.
There have been several failures of the rudder horn attachments. Experience has indicated that these
failures are attributed to improper ground handling technique rather than to unusual flight loads. The design
of the aircraft has placed the fins and rudders at the height which owners and operators have found
convenient for pushing or pulling with their hands when moving the airplane in and out of hangers and along
the ground. Such handling tactics will subject the surfaces to higher loads than those for which they are
designed and should be avoided. The following inspection would be made and corrective action taken when
A load of 10 pounds should be applied to the trailing edge of the rudder while the controls are locked in
neutral position. The trailing edge should not deflect more than one-half inch, nor should there be evidence
of a clicking noise occurring in the vicinity of the center rudder hinge when the rudder is deflected. If the
deflection exceeds ½ inch, the control system should be checked to establish that the deflection is in the
rudder. Once the deflection has been established as in the rudder or if a clicking noise is heard even though
the deflection was less than 1/2 inch, the rudder should be removed and the main spar inspected for cracks.
The outboard skin should also be removed sufficiently to inspect the rudder horn attaching structure and the
roots of the rudder ribs for cracks or damage. Any parts found cracked or deformed should be replaced.
(Except for the cracked rudder ribs, Ercoupe Service Bulletin No. 25, dated July 31, 1953, covers this same
This supersedes AD 53-26-02.