David Piotrowski

1. Structural Health Monitoring (SHM) of B737NG Wing Center Section Shear Fittings with Comparative Vacuum Monitoring (CVM)September 24, 2013 David Piotrowski Delta TechOps - Principal Engineer ASNT Level III – UT, ET, PT Alex Melton Product Line Manager Delta TechOps - NDT Programs Dennis Roach Sandia National Labs FAA Airworthiness Assurance Center John Bohler Level III – ET, CVM Delta TechOps - NDT Programs John Linn Technical Fellow Boeing Tom Rice Sandia National Labs FAA-AANC

2. Team Effort! David Piotrowski John Bohler Alex Melton Dennis Roach Tom Rice Stephen Neidigk Paul Swindell Toby Chandler Andy Chilcott Trevor Lynch-Staunton Brian Shiagec Henry Kroker John Linn Scott Herbert Chris Martin

3. What are we doing? Why? • Airlines/MRO under constant cost pressures • Lots of sensor technologies ready for implementation • FAA previously funded some technologies • Not implemented in industry on wide-scale: • Airline/MRO cost benefit analysis • Lack of certification guidance in regulations • Alternate NDI technique or change in Maintenance Program? • FAA funded this program to move SHM from ‘prototype’ to ‘mainstream’ • Partnership between Boeing/AANC/FAA/Delta/SMS/AEM/AAR • Delta will ‘live through certification’ of SHM app • FAA/AANC provides subsidy to Delta • All vendor items provided separately: Instrument, sensors • Boeing provides program oversight, review • FAA-SACO review • FAA-TAD is the customer – Guidance is the goal • SAE G-11 SHM Aerospace Industry Steering Comm.

4. History & Timeline: CVM Sensors FAA Funding: Lab Work (POD, contamination) Boeing NDT Manual publish 2003 2004 2005 2006 2007 2008 Search begins for application Delta/NW Durability trial Delta/NW Durability trial end 2009 2010 2011 2012 2013 2014 ‘In-service’ find AC CRJ FAA program for ‘guidance’

5. Operator perspective • Vision for SHM usage at Delta • Initially: alternate inspections of difficult to access areas • Inconvenient MTC visits • Hotspot monitoring - AMOCs • Medium term: • Early warning of issues • Future: Condition Based Mtc & Crack Monitoring • ‘Smart Signal’ for engines • OEM Support • Two main hurdles to implementation • Business Cases (payback) • Lack of regulatory guidance, education • Solution: FAA program with Delta for SHM implementation • Delta will write the guidance/blueprint for SHM certification • G-11 SHM => ARP 6461 (draft) SHM is next level of NDT = it’s coming soon

6. SHM Certification & Integration Activity • Certification/usage effort intended to investigate, exercise and evolve the SHM certification path – address all “cradle-to-grave” issues for airlines, MRO vendors, OEMs, and regulators • Identify SHM applications with positive cost-benefit analysis • Customize SHM system to the selected application(s) • Develop validation/certification plan – utilize precedents from existing sensors • Complete SHM indoctrination and training for Delta personnel (engineering, maintenance, NDI), MRO vendors and FAA as needed • Hardware specifications, installation procedures, operation processes, continued airworthiness instructions • Complete modifications to Delta maintenance program as a result of SHM use • Assess aircraft maintenance MROs to determine their ability to adopt SHM and the FAA support needed to ensure airworthiness SHM certification path must be paved

7. 737NG Wing Center Section Front Spar Fitting • Boeing SB 737-57-1309: • Cracking between 21K-36K • Visual inspection for cracking (2”) • Optional Preventative mod after one-time inspection • Mod requires fuel tank entry; inspection doesn’t • Recommend inspection at next opp. • Recommend all 10 fittings changed Economic SB selected – non-safety related

8. 737NG Wing Center Section Front Spar Fitting • From Boeing SB 737-57-1309 • Recommended Accomplishment Time • No compliance recommendation is given currently [Heavy visits] • No repeat inspection intervals given currently • Labor • SB estimates 50 man-hours to accomplish each aircraft inspection. • For repair / modification (fitting replacement) at all ten fitting locations the SB estimates 243 total man-hours. • Kits / Parts • One P/N 002A0001-93 repair / modification kit, at $9,241 ea. • Cost • Inspection only, assuming no damage is found, will cost $4,250 per aircraft • $352,750 for fleet campaign (each inspection round). • Inspection and preventive modification for each aircraft will cost approximately $29,896. • Full fleet preventive modification will cost $2.5 million (81 aircraft). Program selection difficult – mostly due to lack of guidance

9. SHM ‘Springboard’ Plan Proposal • Don’t accomplish optional mod • Remove Fuel-vapor barrier, sealant • Accomplish initial inspections, install sensors, route to cargo bin • Use CVM sensor as an alternate repetitive inspection • Cost savings of 48 man-hours per plane, per inspection (no open-up) • $14,110 per round of inspections - fleet • Unknown repeat interval issue alleviated (i.e. can inspect anytime) • Cost avoidance of $2.4 million (entire fleet) • FAA guidance for Structural Health Monitoring • FAA Funding to subsidize installation(s) • Boeing, FAA-AANC as Team members to assist in approvals • Springboard to other applications! Use Program to ‘pave the path’ for other applications

10. SHM Installation Schematic • Remove FVB • 10 Sensors installed • Snap-click connectors • Tubing routed down front spar • Sensor Lead Sockets collected at common point Aft of Cargo Bin • Easy access via Cargo Bin

11. SHM Installation Schematic

12. SHM Installation Schematic View Looking Down Along Forward Spar View Looking Aft at Forward Spar

13. SHM Installation Schematic • PM200 instrument • Hook-up SLS • Take readings

14. SHM Program Update • Status - Internal: • ~7 months to approve, including changing approval requirements • EP-12 Financial Form issues • EA/AA Dual Author, AMDS cards authored • Materials (repair/modification kits) • Planning • Process Control = 3 months to ‘open’ • Priority Level • Organizational changes – merger fallout & others • SHM Vision presented to Sr. Mgmt Nov 2012 • April 2013 = Process for project approval changed • Operational Reliability Team • Engineering Project Approval Board Laborious internal process for approval

15. SHM Program Update • Status - External: • AAR Coordination visit October 2012 • SHM Workshop – ABQ November 2012 • AAR visits for measurements, layout; dry-run (June 2013) • Delta-Sandia-AEM coordination for procedure development, layout, and installation drawings • Initial Installs: • AAR-IND visit Aug 28-30 for install unsuccessful • Fittings already contained small cracking, but not in sensor area • AAR has found cracks on previous 737s • Discovered on Zonal, GVI Inspection • AAR tribal knowledge of other operators’ higher-cycle aircraft • AMDS Card changes to alleviate • Next aircraft attempt 9/25-27 Thorough collaboration & coordination required

16. Risks Range of risks were discussed, vetted

17. Executive Summary Two main hurdles to implementation Business Cases (payback) Lack of regulatory guidance, education Solution: FAA program to move from ‘prototype’ to ‘mainstream’ Delta will write the guidance/blueprint for SHM certification AAR-Indy will perform labor for installs Vendor provides instrument, kits Sandia = Program Management Extensive coordination Internal: NDT Programs, Fleet Engineering, Supplier Ops, Finance, Planning, Maintenance Programs, Process Control External: Delta-Sandia-AEM-SMS-Boeing-AAR Project completion: Path paved for future SHM adoption

18. Questions?