Monday, February 27, 2012

Controls and instrumentation - Warning systems

want to read about : Controls and instrumentation - Vibration
Warning systems
48. Warning  systems  are  provided  to  give  an indication of a possible failure or the existence of a dangerous condition, so that action can be taken to safeguard the engine or aircraft. Although the various systems of an aircraft engine are designed wherever possible to 'fail safe1, additional safety devices are sometimes  fitted.  Automatic  propeller  feathering should a power loss occur, and automatic closing of the high pressure fuel shut-off cock should a turbine shaft failure occur, are but two examples. On some engine types, the fuel system is fitted with a control  to enable the engine to be operated by manual throttling should a main fuel system failure occur.

49. In addition to a fire warning system (Part 14), a number of other audible or visual warning systems can be fitted to a gas turbine engine. These may be for low oil or fuel pressure, excessive vibration or overheating. Indication of these may be by warning light, bell or horn. A flashing light is used to attract the pilot's attention to a central warning panel (C.W.P.)

where the actual fault is indicated.
50. Other instruments and lights warn the pilot of the selected position of the thrust reverser, the fan reverser or the afterburner variable nozzle, when applicable. Gauges also inform the pilot of such things as hydraulic pressure and flow and generator output, which are vital to the correct operation of the aircraft systems.

Aircraft integrated data system
51. The aircraft integrated data system (A.I.D.S.) is an extension of the 'black box' aircraft accident data recorder. By monitoring and recording various engine parameters, either manually or automatically, it is possible  to  detect  an  incipient  failure  and  thus prevent a hazardous situation arising.
52. Selected  performance  parameters  may  be recorded for trend analysis or fault detection (Part 24).  Existing  instruments  are  used,  wherever possible, to provide the signals to a magnetic tape. Further instrumentation, recording air pressure from points throughout the engine, oil contamination, tank  contents and scavenge oil temperature, may be provided as required for flight recording,
53. After each flight the magnetic tape is processed by computer and the results are analyzed.  Any deviation from the normal condition will enable a fault to be identified and the necessary remedial action to be taken.

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