There is a Vickers Electric Master Chip Detector, which is installed at the combined scavenge return inlets (At the entrance to the Scavenge Filter), and nine Muirhead Vatric screw in Detectors at the inlet of each of:
Front Bearing Housing
Internal Gearbox (HP Rotor)
Internal Gearbox (Rear)
HP Turbine Bearing Chamber
IP Turbine Bearing Chamber
LP Turbine Bearing Chamber
Intermediate and Lower Bevel Gearboxes
External Gearbox
Centrifugal Breather
Ferrous metal is entrapped and conducts electricity across two poles in the detector.
If chips are in the Master, a specific screw in can be checked to ID the type of metal and from whence it came from the nine locations from the scavenge. Bits in Oil are of course, not good.
DERG
Are you referring to an ACARS prompt? Or a Total Care Alert at Derby?? Because the Vickers Electric Master Chip Detector sends a message to the cockpit, but ten minutes after landing. Metal in the master is what alerts the install of magnet probes by Mx to install smaller detectors (The Muirheads) in the nine scavenge ports before next flight, since normal operation of this engine (T9), has the Vickers only installed. Each smaller unit allows for narrowing down the location of the disintegrating part.
Last edited by bearfoil; 18th Feb 2011 at 05:21.