The rudders on Cessna 150s and 152s are the focus of a new Airworthiness Directive.
The AD, issued May 13, is the result of two accidents caused by aircraft entering a spin and the pilots not being able to recover because the rudders traveled past the normal limit. One of the accidents occurred in Canada, the other in Ohio.
The AD, which becomes effective June 17, requires owners to either install a placard in the cockpit noting that spins are prohibited, or replace the rudder stop, rudder stop bumper and attachment hardware, as well as replace the safety wire with jamnuts.
According to a report published in the Federal Register, the cost of installing the placard will be about $80 per airplane. The cost of installing the rudder bumper modification kit is estimated at $410.
According to Jane’s Encyclopedia of Aviation, 23,836 Cessna 150s and 1,541 Cessna 152s were manufactured between 1958 and 1977. The planes are often used at flight schools for spin training and as a more economical alternative to the larger, more expensive-to-rent Cessna 172.
The Notice of Proposed Rule Making for the AD was issued in April 2007. Critics of the proposal pointed out that the two aircraft involved in the accidents were not airworthy prior to flight. The comments further stated that the recommended replacement of the rudder stop, rudder stop bumper attachment hardware and replacing the safety wire with jamnuts is an overreaction.
In the Ohio accident investigators determined that the rudder stop had been installed upside down and the functionality of the rudder stop was compromised.