EWIS Investigation
If you are in a position where there is a need to assess the condition of an aircraft’s wire system, there are several options. To determine the impact of wire problems with the fleet, maintenance logs and interviews with support staff are recommended. Also a viable option is to closely examine the existing wiring systems with analysis technologies. The patented Lectromec DelTest provides an option to those seeking a viable means of determining their current wire condition (our clients have often used this after unknown damage from installation or maintenance actions).
Remaining Service Life Prediction
If there is a need to determine what will be the wire condition in five or ten years, then another approach is necessary. Not all insulations degrade under the same conditions, but the process of wire degradation assessment shares a common thread. The most common aircraft wire types are the following:
1. Polyimide
Often referred to by the DuPont trade name Kapton™, polyimide was introduced as a wire insulation in the 1970’s. Lectromec offers two assessment methods to determine the degradation of polyimide insulation. Lectromec’s analysis of polyimide wire constructions include the WIDAS and the Inherent Viscosity techniques.
2. XL-ETFE
Cross-linked ETFE was developed as a wire insulation to provide a polymer with better physical abrasion resistance than PTFE. In 2012, Lectromec developed a degradation model and assessment method for this material.
3. Composite
This is the newest of the three wire insulation materials presented here. With polyimide on the inside and PTFE (trade name Teflon™) on the outside, this offers a solution with a chemical resistant top layer and a bottom insulation layer that provides strength to withstand mechanical stresses. Lectromec offers two assessment methods. Contact Lectromec to learn more about these assessment methods.
4. Other Types
For other wire types not enumerated above, Lectromec has developed a generalized degradation assessment process that can be used to determine remaining service life.
Although the degradation assessment methods here are specifically designed for wire insulation, other EWIS components can be added (e.g. circuit breaker, relays, connectors, etc.) to provide a complete review and assessment of an aircraft’s EWIS. The overall process is agnostic as to which assessment method is used as long as the assessment method is able to show where it is in the lifecycle.
Using these assessments makes it possible to maintain the aircraft’s reliability and spread out the cost of EWIS replacement across multiple maintenance cycles. Additional information on how these assessments can be integrated into life extension projects (SLEP) is available.