European safety regulators are instructing operators of Airbus A300-600s to check for incorrect installation of pitch uncoupling units.

The units are designed to prevent accidental asymmetric deflection of the elevators. If one fails to function properly, it can lead to a loss of control during take-off.

But in an emergency airworthiness directive the European Aviation Safety Agency says that an A300-600 operator found the mechanism installed in an incorrect location, with the pitch uncoupling unit inverted, on one of its aircraft.

After inspecting other A300-600s in its fleet a second aircraft was found to have the same problem.

"Had this routine maintenance check, which was accomplished for other purposes, not been carried out, the incorrect installation could only have been detected during the accomplishment of the pitch uncoupling functional test," says the EASA directive.

EASA also points out that another maintenance task - an operational test of pitch uncoupling - only validates the condition of a relevant solenoid.

It is instructing operators of A300-600 twinjets to carry out a visual inspection of the unit, within 14 days, to ensure that it is correctly fitted.

Source: Flight International