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IATA 11th MCC & WMS © Jorge Leite @ TAP Maintenance & Engineering23 Sept 2015

Case studies, lessons learnedand delays caused byMaintenance Errors23/Sept/2015

Jorge LeiteVP Quality & SafetyTAP Maintenance & Engineering


Summary

1. Maintenance Error

2. Some Statistics

3. Case Study

4. Actions


1. Maintenance Error


1. Equipment failure

2. Hazards

3. Human Error (active failures and latent conditions)

4. “Bad luck”

5. Combinations of all above

We must accept there are Human Errors and Hazards in the systemLe Bourget Air Show, Paris, 1st A380 public flight, 20/Jun/2011

Very high reliability (higher than 99%)Redundant features and systemsDifficult to enhance significantly

Average reliability(75% to 85%)

Not much to do

Avoid alignment

Origins of an Incident


Hazards and Human Errors

Human ErrorHazards

1. Identify the Hazard2. Evaluate the event’s URGENCY3. Evaluate Inherent Risk (initial)4. Decide on Tolerability5. Control / Mitigate Risk6. Re‐evaluate Residual Risk

Operational Errors

Latent Conditions(Latent Failures)

• Organizational factors• Unsafe supervision• Pre‐conditions for unsafe acts

• Just Culture• Process Management

Healthy Safety Culture

Effective Reporting

Evaluation ofindividual errors

Violations

Active Failures(Unsafe Acts)

• Slips• Lapses• Mistakes


Failures and Barriers

James Reason’s causal model

Barriers (Safety Nets)


The “Error Zone”

MENTAL

PHYSICAL

ORGANIZATIONAL Training

Complexsystems

Insufficientequipment

Incorrect orinaccessibleprocedures

Unclearmaintenance data

Lighting

Noise

Workcolleagues

Distraction

Climaticconditions

Temperature

AssemblyInstallation

Self‐inducedpressure

Team work

Commercialpressure

WorkloadInsufficient tools

MemoryStress

Perception

Attitude

KnowledgeCommunication

Concentration

MotivationComplacencyAlert state

Health

Vision

Drugs

Medication

AgilityWeightFatigue

Hearing


Chain of Events

Events in aviation are easily visualized using a Bow Tie diagram, connecting FTA (failuretree analysis) and ETA (event tree analysis)

UndesirableEvent(RISK)

Multiple Causes(Safety Events)

MultipleEffects

(Outcomes)

Preventioncontrols

Recoverycontrols

FTA – Fault Tree Analysis ETA – Event Tree Analysis

HAZARD

(Barriers)

Prevent Recover

Loss ofcontrol

MultipleConsequences

Etc.

Impacts

Conseq 1

Conseq 2

Conseq 3

Conseq 4

Conseq 5

Conseq 6

(Barriers)


Causes and Contributive Factors

Supervision, Planning

Organization, Procedures

Manufacturers, Suppliers

Authorities, State, Economy

Human

The Sharp End

The Blunt End

Work environment

“I have not used the Maintenance Manual”

Why?

“Because it was not available”

Why?“Because we have online manuals only and the computerterminal was down”

Why?“Because the electrical plugs in the shop were not working”

Why?“Because there was rain falling from the ceiling, so thefacility maintenance guys switched off the mains”

Why?“Because there is no money to repair the roof”

Direct Cause:Maintenance Manual not used

Root Cause: financial problems


Latent Conditions

Johannesburg, 22/Dec/2013


2. Some Statistics


51%

5%5%

4%3%2%

1%1%

1%

1%

26%AirlineEnvironmentAircraft system/componentsEngineMaintenanceRampAircraft designCabinATC3rd partyNot allocated

Source: CAA‐UK CAP 1036 (Jun/2013)

Fatal AccidentsWorld Commercial Fleet (Jet and Turboprop, + 5700 kg): 2002 ‐ 2011

It is estimated that 70% to 80% of all accidents occurred in commercial aviation involvedHuman Error

Main Causes of Fatal Accidents

Source: Boeing Aero QTR_02/07

Humancauses

Machinecauses

Machinecauses

Humancauses

1903 Today

0%

100%

50%

80%

20%


Maintenance Error by Type and ATA Chapter

39%

16%

12%

11%

7%

6%

6%

2% 1% Type of Error

Installation errorInattention (damage)Poor inspection standardsApproved data not followedOtherServicing errorPoor planningPoor standard practicesMisinterpretation of approved data

Source: CHIRP via Skybrary

0

20

40

60

80

100

120

140

Error by ATA chapter

Source: CHIRP via Skybrary

Aviation industry studies have found that the origin of as many as 20% of all in‐flightshutdowns can be traced toMaintenance Error


53%29%

8%

10%

Error Type

Omissions

Incorrect installation

Wrong P/N or S/N

Other

Boeing Study: 122 maintenance occurrencesinvolving Human Factors

Maintenance Error by Subject

Lapses, omissions and incorrect installation of components and parts are the mostcommon maintenance errors

Top 10 CommonMaintenance Errors1 Incorrect / incomplete installation of components

2 The fitting of wrong / worn parts

3 Electrical wiring discrepancies (incl. cross connection)

4 Damage on installation

5 Loose objects (tools, etc.) left in the aircraft

6 Component / part not installed or missing

7 Inadequate lubrication

8 Access panels, fairings or cowlings not secured

9 Fuel or oil caps / panels not secured

10 Equipment / system not activated or deactivated

Sources: Skybrary, Eurocontrol, FAA

Most common maintenance errors are not complicated stuff !


In Engine maintenance, the following main errors have been identified

20% to 30% of IFSDs cost at least 500.000 USD 50% of delays due to engine problems cost

9.000 USD per hour 50% of cancelled flights due to engine

problems cost an average of 66.000 USD per cancellation

Maintenance Error in Engines

Top 10 Errors in Engine Maintenance1 Borescope plug not reinstalled

2 Engine fuel pump gasket seal not fitted

3 Engine attachment bolts incorrectly fitted

4 Anti‐ice valves locked out

5 Fire bottle squibs / tubes not fitted

6 Fuel tube not secured

7 Main Chip Detector (MCD) not fitted

8 Spinner Cone fitment not completed

9 Access panel doors or covers not secured

10 Careless installation of o‐ring

Sources: CHIRP via Skybrary, FAA


Source: Airbus Maintenance Briefing Note: MAINT – HUM_PER – SEQ 02 – REV 01 – JULY 2007

Not using the technical documentation is themost common maintenance violation

Performing a task based on previousexperience, without using or checking theappropriate procedure, is the second mostcommon maintenance violation

Maintenance Violation


3. Case StudyFan Cowl Door Loss in Flight


Some Mediatic Events

24 May 2013

Doors on both engines of emergency landing British Airways flight “were left unlatched”

Flight BA762 was forced to make an emergency landing shortly after takeoff from Heathrow. Smoke and fire were seenpouring out of one of the engines of the Oslo‐bound Airbus A319, which had 75 passengers and 5 crew on board.

The first flight of the day followed scheduled overnight maintenance, which required opening the Fan Cowl Doors on bothengines to check the IDG oil levels. Latches were left open behind when the work was re‐planned (aircraft swap error).Pilot’s walk‐around failed to detect the problem.


Some Mediatic Events

12 Aug 2013

Left‐hand engine cowl detached on takeoff and resulted in damage to the rear fuselage and rudder of the aircraft

EasyJet A320 loses Fan Cowl Door on takeoff from Milan.

One of EasyJet's Airbus A320s sustained cowling damage to one of its engines shortly after takeoff from Milan Malpensa,forcing a return to the airport. The aircraft had been operating flight 2715 to Lisbon on 12 August with 174 passengersand 6 crew members on board.


Airbus “Safety First” July 2012

The Airbus “Safety First” magazine (issue 14) dated July 2012, contained an article relating to the prevention of Fan Cowl Door loss.

At that time, there had been 32 reported Fan Cowl Door detachment events, 80% of whichhad occurred during the takeoff phase of flight.

On some occasions, significant damage wascaused to the aircraft, however none of theseevents had resulted in a subsequent engine fire.


Airbus “Safety First”


Airbus Early Recommendations

Following previous events of Fan CowlDoor separation on A320 familyaircraft, Airbus recommended thatoperators strictly adhere to AMM task71‐13‐00 for proper latching andclosing of Fan Cowl Doors after eachmaintenance action requiring cowlopening.



The Airbus A320 family Flight CrewOperating Manual (FCOM) and Standard Operating Procedure PRO‐NOR‐SOP‐05 for the exterior walk‐around includes a check on each engine that the Fan CowlDoors are closed and latched.

To perform this check it is necessary to crouch down so that the latches are visible.


Fan Cowl Door Loss: Facts

38 events on A320 family (CFM56 and V2500 engines) since 1992(actual A320 fleet: 300 operators, 6700 aircraft)

30 operators impacted (90% operators not impacted) Additional events on B737CL and B737NG families Similar problem also on Bombardier, Embraer, Sukhoi and ATR

Events qtyFlightcycles/10M

80 MFC

A320 family fleetSources: Airbus, EASA


Fan Cowl Door Loss: Causes

Root cause 100% human error during Fan Cowl Door handling To date, all events have been the result of Maintenance 69% of events occurred after IDG oil level check

Main contributive factors(Human Factors and Organizational Factors)

Distraction, Fatigue, Lighting, Workload, Commercial Pressure, etc. Failure to follow proper work sequence Sequence interruption Unexpected alteration of the work planning


Fan Cowl Door Loss: Causes

In all events, analysis shows that latches of the Fan Cowl Doors were either unlocked ornot properly hooked and secured. This condition remained undetected during theexterior walk‐around preceding departure, leading to air scooping and subsequent cowlseparation.


4. Actions


Fan Cowl Door Loss Interim Solutions

Communications since 1992, OIT, FOT Maintenance Briefing Notes Safety Conferences Training Videos Aircraft Maintenance Manual (AMM) updates Service Bulletins (SBs) EASA Safety Information Bulletin (SIB) 2015‐15 (31 Aug 2015) Future Airworthiness Directive (AD) Special condition CS 25.1193 on all new certification applications Etc.


Fan Cowl Door Loss Solutions

New latch, key and safety flag

Fluorescent latch paint

Nacelle “LOOK” stickers

AMM Log Book entry “Fan Cowl Doors have been opened” Install Fan Cowl Safety Flag when opening Fan Cowl

Doors


Fan Cowl Door Loss Prevention

Walkaround procedure

Transit check jobcard: specific FCD entry


Fan Cowl Door Loss Prevention

Operator training and awareness Further retrofit enhancements to avoid risk due to human factors New engine models: introduction of new design features

Electronic monitoring system IDG oil level check w/ dedicated access door Red external indicator

Sources: AirbusSources: Airbus


Management of Change

On 01 October 2013, the Thomas Cook Group introduced a new brand symbol, known asthe "Sunny Heart". The fleet received a new white, yellow and grey livery, featuring thenew symbol on the tail fins.


Management of Change

Interesting questions:• How did Thomas Cook manage this livery change?

• Are the latches still painted fluorescent orange?

• If so, are they visible over orange fan cowl doors?

…!?


Thank you !

Jorge LeiteTAP Maintenance & EngineeringVP Quality and Safety

[email protected]‐mro.comwww.flytap.pt

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