The US Federal Aviation Administration (FAA) has issued an airworthiness directive (AD) that restricts the speed of early model V-tail Raytheon Beech Bonanza general aviation aircraft because of the possibility of in-flight tail surface vibrations.
The Aircraft Owners and Pilots Association (AOPA) says that the AD, which restricts flight of Model 35, 35R, A35 and B35 Bonanzas built between 1947 and 1950 to below 125kt (230km/h), must be followed up with work by Raytheon and the FAA to develop a permanent fix.
In the past decade, there have been a dozen confirmed reports of in-flight tail surface vibration involving the general aviation aircraft. AOPA says there is no clear-cut explanation.
The only common thread seems to be high speed and turbulence, says the trade group, which notes that many of the aircraft involved had properly balanced and rigged ruddervators, the combined elevator and rudder is unique to the V-tail aircraft.
AOPA acknowledges that it will take time to solve the problem because Raytheon and the FAA have examined this issue many times before and have failed to find any obvious solution.
Source: Flight International
