RISK IN THE MAINTENANCE ENVIRONMENT

1. RISK IN THE MAINTENANCE ENVIRONMENT ROYAL AERONAUTICAL SOCIETY ENGINEERING MAINTENANCE STANDING GROUP CONFERENCE AAIB FARNBOROUGH, 10 OCTOBER 2007 Alan P Simmons M.Sc., C.Eng., M.R.Ae.S. Principal Inspector of Air Accidents, Air Accidents Investigation Branch, United Kingdom EMSG Conference 10 October 2007 AAIB Farnborough

2. EMSG Conference 10 October 2007 AAIB Farnborough

3. PRESENTATION OVERVIEW SAFETY SYSTEMS AND HUMAN PERFORMANCE MAINTENANCE ERROR AND BUSINESS RISK REMEDIAL MEASURES EMSG Conference 10 October 2007 AAIB Farnborough

4. SAFETY SYSTEMS AND HUMAN PERFORMANCE IN MAINTENANCE Our safety systems have evolved: • Checking/inspecting: Quality Control • Controlling the production process: QC, TQM • Managing safety: MEMS, SMS EMSG Conference 10 October 2007 AAIB Farnborough

5. SAFETYMANAGEMENT SYSTEMS SAFETY SYSTEMS AND HUMAN PERFORMANCE IN MAINTENANCE EMSG Conference 10 October 2007 AAIB Farnborough

6. LIMITATIONS OF HUMAN PERFORMANCE Perception and Cognitive limitationsOptical and Auditory limitationsTunnelling and focusing SAFETY SYSTEMS AND HUMAN PERFORMANCE IN MAINTENANCE Man errs as long as he strives. Goethe EMSG Conference 10 October 2007 AAIB Farnborough

7. ERROR TYPE MAINTENANCE EXPERT DATA ASSESSMENTSkip a step 0.15 0.001Skip a task 0.026 0.001Ignore a warning/caution 0.042 0.013Intentionally deviate 0.042 0.32Improperly remove/replace 0.033 0.02Improperly repair 0.089 0.0023Incomplete installation 0.089 0.01Improperly adjust 0.09 0.1Allow/cause debris to enter 0.17 0.01 SAFETY SYSTEMS AND HUMAN PERFORMANCE IN MAINTENANCE Source Ostrom et al, INEEL EMSG Conference 10 October 2007 AAIB Farnborough

8. PROCEDURES MITIGATE RISK OF HUMAN ERROR Clear documentation Parts kits Checklists Inspections Function checks Even pre-flight checks SAFETY SYSTEMS AND HUMAN PERFORMANCE IN MAINTENANCE EMSG Conference 10 October 2007 AAIB Farnborough

9. WHY PROCEDURAL ERRORS UNDERMINE SAFETY: Clear documentation is useless if not usedParts control cannot work if uncontrolled stocks are heldIndependent Inspections must be truly independentFunction checks must be carried out SAFETY SYSTEMS AND HUMAN PERFORMANCE IN MAINTENANCE EMSG Conference 10 October 2007 AAIB Farnborough

10. Can your maintenance staff actually perform the required inspections? EMSG Conference 10 October 2007 AAIB Farnborough

11. Do you have uncontrolled small parts? EMSG Conference 10 October 2007 AAIB Farnborough

12. Do your engineers improvise? EMSG Conference 10 October 2007 AAIB Farnborough

13. Are your engineers under pressure to avoid ground runs at night? EMSG Conference 10 October 2007 AAIB Farnborough

14. Do your engineers sign off task cards sight unseen? EMSG Conference 10 October 2007 AAIB Farnborough

15. Is the Approved Data correct and is there a viable procedure to amend errors? EMSG Conference 10 October 2007 AAIB Farnborough

16. MAINTENANCE ERROR AND BUSINESS RISK EMSG Conference 10 October 2007 AAIB Farnborough

17. MAINTENANCE ERROR AND BUSINESS RISK EMSG Conference 10 October 2007 AAIB Farnborough

18. Most maintenance error events investigated by AAIB are INCIDENTS not ACCIDENTSMaintenance related incidents form a larger proportion of total maintenance related events investigated by AAIB than accidentsIncidents are less spectacular but very expensive MAINTENANCE ERROR AND BUSINESS RISK EMSG Conference 10 October 2007 AAIB Farnborough

19. MAINTENANCE ERROR AND BUSINESS RISK EMSG Conference 10 October 2007 AAIB Farnborough

20. … MAINTENANCE ERROR AND BUSINESS RISK EMSG Conference 10 October 2007 AAIB Farnborough

21. MAINTENANCE ERROR AND BUSINESS RISK Procedural deviations are at the root of many maintenance related events Maintenance error arising from non-procedural practices incurs a dual risk to the business: 1 The risk of exposure to loss (loss of safety,earnings) 2 The risk of fines, litigation, denied insurance claims EMSG Conference 10 October 2007 AAIB Farnborough

22. THE COSTS OF A MAINTENANCE EVENTRework/re-instatement costsAdditional hangar time costsRepair costs for consequential damageMaintenance re-scheduling and knock-on delaysOperational schedule related costsCompensation costsCost of hiring a replacement aircraftBusiness costs – obtaining and retaining market share MAINTENANCE ERROR AND BUSINESS RISK EMSG Conference 10 October 2007 AAIB Farnborough

23. Recent examples from AAIB investigations into actual incidents: A technician assembled propeller de-icer boots without the required sealant materials, which were difficult to obtain. The boot detached causing injury and damage. A mechanic assembled a helicopter rotor head without the required shims, because the job was urgent. The helicopter suffered severe vibration and blade cracking. After major maintenance, an engineer stamped up a number of job cards to close all remaining open panels, but not all the panels were open at the time. One of the closed panels was not properly closed and latched. The panel came off and penetrated the cabin. EMSG Conference 10 October 2007 AAIB Farnborough

24. MAINTENANCE ERROR AND BUSINESS RISK • How can we reduce the risk of maintenance error? • By promoting: • A culture which rewards procedural compliance… • …and discourages violations • Error-tolerant systems • Reporting systems which work and are used • An analytical approach to risk EMSG Conference 10 October 2007 AAIB Farnborough

25. MAINTENANCE ERROR AND BUSINESS RISK In 1994 AAIB stated: ‘The Civil Aviation Authority should formally remind engineers of their responsibility to ensure that all work is carried out using the correct tooling and procedures, and that they are not at liberty to deviate from the Maintenance Manual but must use all available channels to consult with a design authority where problems arise; if full compliance cannot be achieved the engineer is not empowered to certify the work’. [Airbus A320, G-KMAM AAIB Report 2/95, Safety Recommendation 94-41] This is still the only way forward. EMSG Conference 10 October 2007 AAIB Farnborough

26. THANK YOU FOR YOUR ATTENTION EMSG Conference 10 October 2007 AAIB Farnborough