FOCA does advise holders, operators and maintenance facilities of these types of helicopters to strictly adhere to the manufacturer inspections requirements and limitations.
Important safety information concerning the required visual inspection of Tail Rotor Control Cables of the Helicopter Type ‘Aérospatiale SA 315 B (Lama)’ and Types ‘Alouette II’ and ‘Alouette III’
FOCA SAND-2010-002
Cause
A Swiss operator has reported the rupture of a Tail Rotor Control Cable. The corresponding maintenance manual requires for periodical inspection of the condition of these types of cables. Nevertheless such cable has ruptured in-service, but the helicopter could be landed safely. An in-depth investigation of the failed component has shown excessive wear within the cords and the wires of the cable. Furthermore the polymer sleeve of the cable was from inside coloured black.
These information and safety relevant situation prompted the Swiss Federal Office of Civil Aviation (FOCA) to issue an information bulletin on this topic. The aim here is to ensure that holders and operators of these types of helicopters will be alerted and may be aware that strict adherence to the manufacturers inspection requirements is essential to as-sure safe operation.
Recommendation
The corresponding maintenance manual provides the instruction to replace the cable if one of the following criteria is fulfilled:
- the cable is partially unprotected due to missing portions of the polymer sleeve
- the polymer sleeve is penetrated by one or multiple wires
- the polymer sleeve shows internally intense discoloration (black) in whole circumference on a portion exceeding a length of 10 mm
Any observations and irregularities resulting in operational deficiencies should be reported to the state of registry as well as to
the TC-holder.
