Identification of Aging Aircraft Electrical Wiring

Group Members:David Bryant

Yuto ShinagawaShaun Steinbarger

Sponsors:Dr. R. O. Stearman

Marcus Kruger

BSS Engineering Inc.

Overview

• Background Information• Project Objectives• Experimental Setup• Problems Encountered• Laboratory Aging Results• Age Analysis Results• Recommendations• Conclusion

Background Information• Navy and Air Force discover problem in the 1980s• Commercial aviation industry becomes concerned

– Swiss Air 111 and TWA 800– Substantial number of planes contain faulty wiring

• Aircraft industry is seeking a method to discern age of aircraft wire

Triboelectric EffectDefinition: creation of charge imbalance due to contact

separation resulting in unwanted interference

Triboelectric EffectSolution to the problem: relate triboelectric effect to

the age of a wire in hopes of identifying faulty wiring

Project Objectives

• Find standards in wire aging techniques

• Design laboratory experiments• Successfully simulate wire aging• Monitor the triboelectric response

of nominal and aged wires

Distribution of TasksProject Manager:Shaun Steinbarger

Senior Engineer:David Bryant

Senior Engineer:Yuto Shinagawa

Wire AgingChief Engineers:

David Bryant Shaun Steinbarger

1. Logistics2. Design3. Implementation

Age AnalysisChief Engineer:Yuto Shinagawa

1. Test Design2. Test Implementation3. Data Analysis

Alpha Wire 1632• Material – rubber• 20 Gage

– 1.02 mm insulation thickness

– 3.18 mm diameter • Single Conductor• Temperature

Range– -30°C ~ 90°C

• Cost• Twisted pair

Laboratory Aging

• CE Environmental Chambers– Heat Test– Humidity Test– Chemical Solution Test

Saltwater Jet-A fuel with Prist additive

15 specimens per test – 4 ft/specimenSpecimen removed every 3½ days

Heat & Humidity Tests

• Temperature – 120°F

• Humidity – 70%• Temperature –

75°F

Chemical Solution Test

• Salt Water– Salinity – 8 fl.

oz./gallon

• Jet-A Fuel

Approved 5 gallon container

Ambient temperature - 100°F

Age Analysis I

Data Acquisition System Amplifier Shaker

Wire Circuit

Signal Analyzer

Age Analysis II

Signal Analyzer

Amplifier

Data Acquisition System

Age Analysis III

Wire Circuit (closed)

Electromagnetic Shaker

Problems Encountered – Laboratory Aging

• Heat Test – Desired Temperature 170°F– Heat Lamp – Testing terminated early

Problems Encountered II – Age Analysis

• Software Packages– Hewlett Packard 35660A– Ideas– LabView– HP3566A/67A

• Three Separate Test Runs– Closed Loop Test– Electromagnetic Interference (EMF)– Inconsistent results

Results I – Laboratory Aging

• Humidity/Heat aging tests – No visual/physical results

• Jet-A– Expanded in diameter

and length– “Slippery” copper wire

• Salt H2O– Corrosion of copper

Results II- Age Analysis Specimen Length of Exposure Response Amplitude

(days) (decibels)

Nominal 1 0 -79.00Nominal 2 0 -70.47Jet-A 1 3½ -57.96Jet-A 5 17½ -52.79Jet-A 10 35 -52.06Salt 1 3½ -52.90Salt 5 17½ -55.32Salt 10 35 -63.79Humidity 1 3½ -54.11Humidity 5 17½ -53.71Humidity 10 35 -55.29Heat 1 3½ -55.83Heat 5 17½ -53.65Heat 10 35 -53.90

Specimen Nominal 1 - Twisted Nominal 2 - UntwistedTest (decibels) (decibels)

1 -53.49 -62.642 -76.94 -76.753 -63.39 -52.564 -77.67 -73.095 -54.30 -67.30

• No trends in data

• Inconsistent results

Project Objectives• Find standards in wire aging

techniques

• Design laboratory experiments

• Successfully simulate wire aging

• Monitor the triboelectric response of nominal and aged wires

Success

Success

Success

Unsuccessful

Recommendations I• Laboratory Aging

– Reconfigure Heat Test• Locate an environmental chamber capable of 170 °F• Expose wire to extreme cycles in temperature

– Discontinue Humidity Test• Expose specimens to combinations of tests

– Cycle procedure» 1 week Jet-A» 1 week Salt H2O» 1 week Heat

Recommendations II

• Age Analysis

– Become proficient with Ideas

– Eliminate all outside variables

– Develop more consistent testing procedures

Conclusions• Inconsistent results

– Data does not provide any definitive trends between age and triboelectric response

– Current experimental setup does not guarantee elimination of external disturbances

• Change in scope of project– Find a relationship between the aged state of a wire and its triboelectric response– Design and evaluate experimental procedures so future groups may base their continuing research upon them

Any Questions ???