Zenith Aircraft Company
Mexico Memorial Airport
Mexico, MO 65265-0650 USA
(573) 581-9000
WARNING:
CH 601 and CH 701 Rudder Pedals
February 17, 1998
Although a large number of the above aircraft have many hundreds, even
thousands, of hours without any problems, it has come to our attention that
lately several rudder pedals have been broken during operation (usually on the
left pilot side pedal).
From the designer’s standpoint, this can happen when:
- Using the wrong material and/or technique;
- Modifying the geometry of rudder and/or brake pedals;
- Using the rudder pedals in a very rough manner (we have very little "feel"
in our legs and feet);
- Applying the brakes by pushing excessively hard on the pedals;
- A combination of the above which may cause cracks in the pedal assembly
leading to failure.
WHAT YOU NEED TO DO:
- Check the bottom of the pedals near the welds to the horizontal tube. Do
not fly the aircraft if you detect cracks or deformation of the tubes and/or
welds.
- Replace the existing rudder pedals with new ones made with 4130N tubing, ¾
x 0.049" or 0.058" (use welding rod AWS-A.5-2-69 (RG60), or
Another solution is to weld triangular gussets
(4130N t=.032" or .040", or steel t=.080" / gauge 14) on each side of
the tubes, as shown below:
See Drawing 6-F-17 (601 Series) or 7-C-4
(701)
For more information:
Nicholas Heintz, Zenith Aircraft
Company
Tel: 573-581-9000
Fax: 573-581-0011