Bonanza Trouble Reports



Trouble reported with Hartzell propeller clamps. Pilot / owner of A35 Bonanza reported that after having new beefed up Hartzell blade clamps installed, he is experiencing a problem of new clamps contacting and chafing with the prop spinner.

  Engine Air Filter - Brackett air filter

Beech Model F-35

After installation of a Brackett air filter, the submitter found the manifold air pressure (MAP) was 2 inches (Hg) lower at takeoff power than with the original filter installed. An investigation determined the differential pressure was opening the alternate air door. The alternate air door began to open at 21 inches MAP, and was fully open at 23 inches MAP. A new alternate air door spring was installed, and another operational test produced the same result. From reading this report, one would conclude the Brackett air filter was not allowing sufficient airflow to the engine. This problem was presented to the manufacturer who stated this was not normal. According to Brackett, "one should normally see approximately 2 inches H20 drop or 1/5 inch Hg." This air filter system has been in use for many years, and the manufacturer is not aware of this type of previous occurrences. A review of the FAA Service Difficulty Reporting (SDR) data base revealed 53 entries associated with Brackett air filters since 1986. Only two of these reports cited symptoms described in this article. The cause of one report was attributed to excessive oil on the filter element, and the other to installing the assembly "backward." Most of the other reports concerned water or ice saturation of the filter element during operation and deterioration of the foam filter element. The exact cause of this defect has not been determined. If additional information is obtained, it will be printed in a future edition of this publication.