more “Why We Need to be ^ Proactive”

1. more“Why We Need to be ^Proactive” • David F King • Deputy Chief Inspector of Air Accidents • Air Accidents Investigation Branch • United Kingdom • Measuring Safety Culture • a Maintenance Human Factors Perspective • 26th April 2004

2. BAC 1-11

3. BAC 1-11

4. Airbus A320

5. Boeing 737

6. Boeing 737

7. COMMON FEATURES • Night shift - Circadian lows - Much Maintenance at night. • Supervisors tackling long, hands-on involved tasks. • Interruptions. • Failure to use the Maintenance Manual - IPC • Confusing -misleading difficult manuals • Shift handovers - poor briefing - no detailed stage sheets • Time pressures • Staff shortages • Limited preplanning paperwork, equipment, spares • Determination to cope with all challenges.

8. Boeing 757 Nosewheel Axle failure • Birmingham to Malaga - uneventful landing. • Exit via rapid taxiway - 20kts vibration. • Aircraft stopped - passengers evacuated via steps. • Inspection - right nose wheel canted over - Outer Bearing disintegrated.

9. Boeing 757 Nosewheel Axle failure • 1725hrs Operator informed - Duty Engineer Right nosewheel bearing collapsed. • Telecon Commander OK towed slowly - consequential damage? Axle change anyway! • Telecon contract maintenance company Two engineers to go to Malaga - no can do!

10. Boeing 757 Nosewheel Axle failure • Another co aircraft due take-off for Tangier 1800hrs Held for divertion malaga with wheels and change kit. • Certifying engineer (LAE) rings in - to check shifts! Aircraft full of passengers - is he available? Feeling tired been Flying microlight - Agrees to go. • 1730hrs Told he is going. • Duty Engineer copies extracts from AMM Torque loading for wheel change NOT ‘Time Limits/Maintenance Checks - mandatory borescope inspection after bearing failure!

11. Boeing 757 Nosewheel Axle failure • 1815hrs LAE arrives at Airport Asks for mechanic to go with him - Only one seat on aircraft! • 1825hrs Aircraft departs for Malaga No opportunity for LAE to check AMM not one on aircraft. Only authorised procedure for nosewheel axle - repair by replacement. • 1830hrs Duty Eng told aircraft jacked Wheel was off & axle was ‘not too bad’. • 1900hrs Avionics Eng takes over as Duty Eng. • 2115hrs LAE arrived in Malaga

12. Boeing 757 Nosewheel Axle failure • 2115hrs LAE in Malaga - asked about length of delay? Damaged wheel already loaded - unaccessible. Saw bush and axle nut damaged - elected to re-use. • Identified axle damage Between bearing lands - 11/2” long 1/16” deep. Could see no ‘bluing’ or overheat on outside of axle. • Decided aircraft OK return Birmingham after blending Informed Duty Eng at Manchester. • Duty Eng concerned no repair limits in Manual. Contacted Boeing 24 hr desk - go to AMM/provide sketch?

13. Boeing 757 Nosewheel Axle failure • LAE used torch in attempt to see inside axle Could not see 7” as Borescope inspection required. Missed evidence of overheating. • Blended damage Using half round file and emery paper. • Did not raise ADD but regarded as temporary repair no drawings or blend limits to work to - no blending allowed. • During inspection distracted Tangier aircraft having refuelling problem - gave advice. • During blending distracted Refuelling problem again - went to assist.

14. Boeing 757 Nosewheel Axle failure • LAE replaced right wheel without problem • Changed left hand wheel. • 2215hrs (1 hour after arrival Malaga) Contacted Duty Eng brief description of damage Aircraft satisfactory for service Axle change should be planned when schedule allowed. • 2259hrs Aircraft Took off. • 0121hrs Aircraft landed at Birmingham Slowed to 12kt when axle failed.

15. Discolouration 400C Region ‘dressed’ since mechanical damage - before fracture.

16. Fracture initiation in dressed region

17. COMMON FEATURES • Night shift - Circadian lows - Much Maintenance at night. • Supervisors tackling long, hands-on involved tasks. • Interruptions. • Failure to use the Maintenance Manual - IPC • Confusing -misleading difficult manuals • Shift handovers - poor briefing - no detailed stage sheets • Time pressures • Staff shortages • Limited preplanning paperwork, equipment, spares • Determination to cope with all challenges.

18. That’s All Folks

19. WINDSCREEN CHANGE • Short staffing - Night shift of 7 down by 2. • Shift Manager does job himself, alone. • A/C remote - took Manager away from his other duties. • Time pressures - AM shift short - aircraft to be washed. • Task between 0300-0500 hrs - time of Circadian lows. • Manager was on his 1st night work for 5 weeks. • MM only used to confirm Job ‘straight forward’. • IPC was not used - IPC was misleading. • The safety raiser used provided poor access.

20. WINDSCREEN CHANGE - SHIFT MANAGER • assumed bolts fitted OK - incorrect bolts 4 years before. • chose bolts by matching - stores below min stock level. • ignored advice of storeman on bolt size. • bolts from open AGS Carousel - faded labels - dark corner. • did not use his reading glasses at any time. • increased torque from 15 lb in to 20 lb in. • didn’t notice excessive countersink or next window different. • didn’t recognise different torque for corner fairing. • rationalised use of different bolts next night doing same job

21. FLAP CHANGE • LAE and team were new to the task. • LAE authorised but A320 rarely seen - 3rd party work. • Planning was a job card - 'change flap' + some tooling. • Maintenance Manual in AMTOSS format. • Tooling deficient or incorrect - no collars for spoilers. • LAE requested experienced help - none available. • Other tasks during delays - changes in tasking. • Task worked in early hours - time of Circadian lows. • Tried task without disabling spoilers - couldn't do. • Spoilers disabled no collars/flags - deviation from MM.

22. FLAP CHANGE • Shift hand over verbal, paperwork incomplete - misunderstanding over spoilers. • Spoilers were pushed down during flap rigging. • Familiarity with Boeing aircraft where spoilers auto reset. • Flaps functioned - spoilers not - a deviation from the MM. • Duplicates were lead by day shift engineer. • Failure to follow Maintenance Manual. • During flight crew Walk round nothing amiss. • Pre-flight check, 3 seconds mismatch control/surface position required to generate warning. • Engineers demonstrated a willingness to work around problems without reference to design authority - including deviations from Maintenance Manual.

23. BORESCOPE INSPECTION • Inspections not in accordance with Task Cards or MM:- • HP rotor drive covers not refitted. • Ground idle engine tests not conducted. • Tech Log wrongly signed completed as in MM • Work originally planned for Line, transferred to base. • Line and Base staff shortages - three Base supervisors. • Minimal preplanned paperwork - Line Maintenance. • To keep authorisation Base Controller did inspections. • A/C remote - took Controller away from other duties.

24. BORESCOPE INSPECTION • Line Engineer gave verbal handover to Base Controller. • Inadequate reference to Maintenance Manual. • Use of an unapproved reference source - school notes. • Poor lighting. • Many interruptions. • Early hours of morning - Circadian lows. • 9 previous occurrences. • Borescope Inspections routinely non procedural. • Quality Assurance system had not identified deviations. • Regulator’s monitoring had not corrected lapses.

25. Although many ingredients are demonstrated to have come together to create these incidents, what if some are there all the time? 1 Fatal Accidents The Heinrich Ratio Accidents 10 Reportable Incidents 30 Incidents 600 Tye/Pearson Bird