Calls For AD To Inspect Rudder Boots

On Wednesday, the National Transportation Safety Board issued Safety Recommendation A-07-33, calling on the FAA to make a current service bulletin mandatory for Cessna 150 operators, in the form of an airworthiness directive.

In response to an April 11, 2005 stall-spin accident near Williamsburg, OH -- in which the rudder of a Cessna 150 jammed during spin recovery training -- the NTSB says operators of the type should heed Cessna Service Bulletin No. SEB01-1, calling for all C150 and C152 models to undergo a one-time inspection at the next 100-hour or annual inspection, to verify that the rudder bumpers are correctly installed on the rudder horn assembly.

Investigators found the rudder boots on the accident aircraft had been installed inverted, and that the right rudder bumper had traveled beyond the rudder stop and had locked behind it -- causing the rudder to jam left at a 35 degree angle, past its travel limit. Both pilots onboard the C150 died when it spiraled down.

The investigation could not determine whether the incorrect installation of the rudder bumpers occurred at the time of production or during the airplane’s maintenance history. Review of the maintenance records indicated no record of work having been performed on the rudder bumpers during the airplane’s 28-year history, according to the NTSB.

The Board added a similar accident occurred on a Canadian C152 in 1998. A CFI and a student pilot were practicing spins, and were unable to recover from one. The CFI was killed, the student pilot sustained serious injuries, and the airplane was substantially damaged. During its investigation, the Transportation Safety Board of Canada (TSB) found that, although the rudder bumpers were installed correctly on this airplane, the rudder had deflected at 34° and had jammed beyond its left travel limit.

The TSB also found the right rudder bumper had traveled beyond the rudder stop and had locked behind it.

FMI: Read The Full NTSB Recommendation (.pdf)