CASA has warned air operators of the dangers of the incorrect routing of aircraft control cables.
CASA is alerting air operators to the problems that can arise due to incorrect routing of control cables after it recently received a number of reports of wrongly routed control cables, which can lead to fatal consequences.
In one case involving a Metro III, a rudder control cable was incorrectly routed over the lower pulley cable pin, instead of being placed between the pulley and cable pin keeper. In only 3.4 hours of flight and six landings since the mistake was made, the cable had badly chaffed against the cable pin.
This caused the cable strands to fray and break, with the cable only being held together by a few strands when the problem was discovered. If the rudder control cable had broken in flight the pilots would have suffered a loss of horizontal axis control of the aircraft, creating the risk of a total loss of control.
In a letter to all certificate of approval holders, CASA’s Director of Aviation Safety, John McCormick, said awareness of the risks caused by cable routing mistakes must be increased.
“Air operators should discuss the matter with their engineers to make sure they were alert to the risks,” McCormick said. “It is vital that aircraft maintainers strictly follow approved maintenance data and instructions when performing tasks such as cable routing.”
Under Civil Aviation Regulation 42G, CASA requires an independent inspection of maintenance carried out on flight control systems to ensure work is done correctly and certified by an appropriate person. For more on CAR 42C click here.
Incorrect routing of control cables can render an aircraft's control surfaces useless. (BAL)
