Bristow S-92A Modifications

Introduction of ICS Extension Cable with Noise Filters

This modification installs noise filters between the pilots ICS outputs on the aircraft and the pilot’s headsets, introduced to remove the noise from the transformer rectifiers.

The noise filters are modified by removing the connector and inline receptacle. The wires are then spliced with a new cable to obtain the correct length. Finally, the connector and inline receptacle are reinstalled.

The modified noise filters are located on the “Z” profile above the L/H and R/H cockpit emergency side windows.

For each filter, two attachment holes are drilled in the “Z” profile composite aircraft structure. The profile is then protected against chafing by adding protective tape to the profile.

A “U” shaped bracket is fabricated from aluminum alloy (2024-T3) with protective tape installed to the lower face. The filter is then located between the attachment holes and clamped into position using the attachment bracket, spacers, screws, nuts and washers.