Plastic two-part detachable flight control column hand-grips fitted on numerous aircraft type.
This Continuing Airworthiness Notice (CAN) is issued to alert operators and maintainers to inspect two-part flight control column hand grips for looseness between the control column and the grip. Any looseness may indicate failure of the plastic mating halves and/or the attachment hardware.
This CAN is prompted by an overseas accident which was due to the sudden separation of the plastic control column grip from the control column and resulted in loss of control at low altitude. Investigation revealed the grip was an approved STC part fitted on an aircraft which was not listed in the STC.
The grip consists of two halves clamped together with two through bolts. The lower bolt also attaches the hand grip to the control column. On the accident aircraft the plastic control column grip separated from the control column due to the presence of cracks in both the upper and lower through bolt boss areas, which resulted in the bosses breaking completely away from the plastic grip halves.
Maintainers and operators must ensure that the aircraft model is listed on the STC before installation of a STC approved part. The CAA strongly recommends operators and maintainers inspect all detachable grips for security on the control column. If any looseness is found between the grip and the control column there may be a number of reasons:
If a grip remains loose on the control column after tightening, accomplish the following:
· Inspect the exterior of the grip in the bolt boss areas for any signs of cracks,
· Inspect for wear due to chafing,
· Inspect the electrical wiring in the grip assembly and determine if the wiring is not caught between the grip halves which may prevent complete clamping,
· Inspect and determined if the fasteners are not thread bound, and
· Accomplish all applicable correct actions before returning the aircraft to service.
For further information refer to CASA AWB No. 27-005 issue 2, dated 8 February 2012 which can be obtained from: http://www.casa.gov.au/scripts/nc.dll?WCMS:STANDARD::pc=PC_90516(external link)
