In recent years, requirements to address the in service training of personnel who are required to perform either Electrical Wiring Interconnect System Inspection (EWIS) inspection, or EWIS Maintenance.
Amongst the training requirements it is necessary to make Maintenance personnel aware of the need to ensure that aircraft EWIS should be maintained with the same level of intensity as any other system in the aircraft.
They also need to recognize that visual inspection of wiring has inherent limitations. Small defects such as breached or cracked insulations, especially in small gauge wire may not always be apparent. Changes have been made in the understanding of what constitutes a General Visual Inspection which is detailed here.
Effective wiring maintenance to deliver the required EWIS standard combines visual inspection techniques with improved wiring maintenance practices and training. To be effective this training is an ongoing and recurrent requirement most effective when it is delivered in the work place.
A new phrase has been developed to promote, the correct attitude to managing the EWIS environment , EWIS maintenance practices should contain a "protect, clean as you go" housekeeping philosophy. This requires, to be taken to protect wire bundles and connectors during work, and to ensure that all swarf, shavings, debris and other contamination are cleaned up after work is completed.
To consider the Term GVI when associated with Electrical Wiring Interconnect Systems General Visual Inspection (GVI):A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to enhance visual access to all exposed surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight or droplight and may require removal or opening of access panels or doors. Stands, ladders or platforms may be required to gain proximity to the area being checked.
A Stand-alone General Visual Inspection (GVI): A GVI which is not performed as part of a zonal inspection. Even in cases where the interval coincides with the zonal inspection, the stand-alone GVI shall remain an independent step within the work card. The Stand Alone GVI becomes an essential element of the EWIS Inspection process for aircraft which are not managed in accordance with the requirements of MSG3.
A Detailed Inspection (DET): In respect of EWIS on occasion an intensive examination of wiring or other installation may be required it is a specific requirement focused on an item, installation, or assembly to detect damage, failure or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirrors, magnifying lenses or other means may be necessary. Surface cleaning and elaborate access procedures may be required.
AMC 20-22 makes It very clear as to the requirements which are to be complied with to ensure the organisation remains in conformity with EASA regulatory requirements. Ultimately in accordance with the terms of the approval issued to Operators and MRO’s It is the Operators and Maintenance Organisation Responsibility to comply with the requirements of Electrical Wiring Interconnect Systems working practices and procedures EWIS as specified in AMC 20-22.
Sofema Aviation Services based in Sofia deliver regulatory training across a range of regulatory areas, please visit www.sassofia.com for details.