Boeing - EEE Parts

1. SSQ 21654 Fiber Optic Cable Anomaly- Root Cause Investigationas a Sustaining Engineering Activity Boeing - EEE Parts David Gill (714) 896-6403 11/5/99

2. Anomaly Description • Original anomaly effect found was high loss during normal production • SSQ 21654 Specification Custodian started the investigation • Hypothesis was that defect was a coating discrepancy • Further investigation analysis indicated an unusual defect was appearing inside fiber core and propagating outward

3. Fiber Optic Cable Anomaly - Initial Indicators

4. Fiber Optic Cable Anomaly - Additional Physical Analysis

5. Preliminary Investigation • Discussions with suppliers, other fiber manufacturing and next assembly user experts indicated they had no experience base of this type of anomaly • Product used widely in military and space applications including other NASA programs • Discussions also revealed that this fiber configuration was the most difficult fiber design and construction that the industry has ever produced • Many have tried but only one source is available for this type of requirement • Investigation data indicated defect appears to be a latent • Entire SSQ 21654 cable shipping history was now suspect unless root cause or most probable cause could isolate shipped cable to a lot(s) related problem • SCAN/TWX issued to collect FO Cable next assembly history

6. SSQ 21654 Experience • No past production experience indicated a latent defect effect was occurring • Early production at W/H level indicated a well controlled process with good distribution related to optical loss and small standard deviation • Later production (Late 98- June 99) indicated poor processing • Many failures had occurred; however, no root cause was performed and anomalies were abandoned in place without detail root cause analysis • Failures dispositioned as mishandling during wire harness installation or other operations which accidentally damaged fiber

7. Early Investigation Techniques • Analysis next centered on determining if wire harness assembly and installation as well as ATPs were credible screens to detect this anomaly • Data determined 100% confidence could not be obtained (or all these types of anomalies would NOT be caught) • Traditional fiber optic failure analysis techniques - SEM/EDXS, optical loss, strength measurement techniques with limited samples have been unable to pinpoint root cause • Additional support from NASA-GSFC (NASA’s FO Center of Excellence) has been requested to aid in investigation • NASA-GSFC is using this type of fiber optic glass on at least two programs • Boeing, NASA, and SSQ 21654 suppliers have now agreed on the go forward plan

8. Forward Plan • Plan is three fold • Historic review of production history • Audit techniques focusing on all probable causes • Physical evaluation using statistically significant data gathering techniques • Careful reflection of material, processing, and other factors based on audit findings that place additional in-line process monitors and inspection points • Careful restart of production line using agreed to in-line process monitoring and inspection and other lessons learned • Product re-qualification

9. High Optical Losses in FO Cables 5A AOE-0588 SSQ 21654 Fiber Optic Cable Anomaly Status - Root Cause Investigation W/H Testing or Mating H/W Error(s) Fiber Optic Cable Design/Manufacturing Error(s) Wire Harness Assembly Tools/Procedure Error(s) FO W/H Design Error(s) Shipping/storage Exposes Cables to High Energy Too Much energy is concentrated at fiber weak point Glass Fiber ManufacturingError(s) Preform/Fiber design Changes FO Cable Jacketing Error(s) Cladding IDSurface not properly prepared FO Cable Testing Error(s) Cladding Material/Supplier or Dimensional Change Outside Jacket Applied too thick Degreasing Material/Process Changes Spectran Improperly Performs testing BICCGeneral Improperly Performs testing Core Material/Supplier or Index Dimensional Changes Outside Jacket Applied with Too Much Heat Initial cladding processing personnel error(s) Testing Performed inadequate Pre-form Processing shrinks material too slow/fast Outside Jacket Applied Too Much Speed Imperfections in ID Test Method/Procedure Unable to detect all anomalies Pre-form Lathe Processing temperatures not controlled properly Fiber laser mic generates sufficient ESD energy Strength Member Too Many Braids Etch materials/.process changes Buffer Tube too Small Strength Member Too Few Braids Glass Draw process too fast/slow Cladding wash material/ process change Pre-form Lathe rotation too slow/fast Buffer Tube too Large Strength Member not Proper Material Glass Draw process too hot/cold Core material not properly processed Buffer Tube not round enough Index Scrubbing Process improperly implemented Index Step Materials Contamination Preform processing personnel error(s) Draw tower error(s) Index processing personnel changes Personnel in tower causes error(s) Drawing tower temperature/speed not controlled Creation of micro gas bubble Index Lathe Processing temperatures not controlled properly Index Step Materials Improperly Applied Tensile test mandrels not performing properly Drawing tower furnace too hot/cold Fiber Coating Material/ Process changes Drawing tower speed too slow/fast Index Lathe rotation too slow/fast Carbon Coating Material/Process variations Polyamide Coating Material/Process variations Drawing tower start/stops or speed not smooth Contamination in Tower Index processing personnel error(s)

10. Plan to Audit • Auditing - Supplier self audits have already been performed • SEA • SSQ 21654 distributor • BICC • Cable jacketer • Spectran • Preform manufacturing • Fiber draw manufacturing • Resources - • 2 engineers for November and half of December • Supplier Support • Travel required • PRODUCT • Audit Report

11. Plan to Evaluate Physical Specimens • Physical evalutation • Specimens obtained during Boeing investigation • Determine quantitative relationships between shipped lots and fiber preforms for defect parameters • Physical anomaly size (bubble size) • Optical loss • Strength • Other defect parameters (coating defect parameters) • Resources - • 1 engineer + 2 technicians for November and half of December • Material evaluation of supplier product • Limited special test setups required • NOTE: Current Production material used in investigation is not part of the sustaining material required • PRODUCT • Anomaly Report

12. Plan to Monitor Production Line Re-start • Production Monitoring during restart • In line process monitoring • Additional tests and inspection points added • Spectran • BICC • SEA(?) • Resources - • 1 engineers for half of December and all of January • Production in-line monitoring equipment may be required • Supplier Support • Travel required • PRODUCT • Zero defect flight hardware • NOTE: Production material not part of sustaining proposal

13. Plan to Requalify Product Line • Product re-qualification (Delta Qualification) • Resources - 1 engineer + 2 technicians for February and Half of March • PRODUCT • Qualified flight hardware

14. Sustaining Resources Required • Resources represent a slight delta to allocated sustaining plan at the WBS level • Some resources would have already been allocated as critical skill retention • Attempts to manage to allocated overall WBS level will take place • Schedule erosion • Delay some design knowledge capture activities • FINAL ROOT CAUSE REPORT will be completed • Activity represent important knowledge for entire aerospace community • Papers will be presented on the findings