airline safety and effects of maintainence alan simmons

8/12/2019 Airline Safety and Effects of Maintainence Alan Simmons

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AIRLINE SAFETY AND THE

EFFECTS OF MAINTENANCE

3rd Annual European Airline Engineering & Maintenance Conference

Zurich, 21-22 February 2007


Airline Safety and the Effects of Maintenance



Review of Maintenance Error Events

The Contribution of Maintenance Error to Accident

Statistics

Safety Systems and Human Performance in

Maintenance

Maintenance Error and Business Risk



PRESENTATION OVERVIEW



…



REVIEW OF MAINTENANCE ERROR EVENTS

ALOHA BOEING 737



…






…




AIRBUS A320 SPOILER INCIDENT



…




BOEING 737 DOUBLE ENGINE OIL LOSS



G-CEPR






777 fuel panel









Procedural deviations

Inadequate regulatory oversight

Inadequate maintenance programme

Failure to respond to cues and warnings

Inadequate promulgated information

COMMON FACTORS IN THESE INVESTIGATIONS






Non-use of available resources

Failure to communicate

Design deficiency

Failure to anticipate effects on the operation of

the aircraft

Inadequate maintenance environment

Human performance limitation

Inadequate management oversight

Incorrect parts or tools

Inadequate knowledge or training



Accident rate plots



THE CONTRIBUTION OF MAINTENANCE ERROR

TO ACCIDENT STATISTICS



Most maintenance error events investigated were

INCIDENTS not ACCIDENTS

Maintenance related occurrences form a larger

proportion of total incidents investigated by AAIB

than accidents.







THE COSTS OF A MAINTENANCE EVENT

Rework/re-instatement costs

Additional hangar time costs

Repair costs for consequential damage

Maintenance re-scheduling and knock-on delays

Operational schedule related costs

Compensation costsCost of hiring a replacement aircraft

Business costs –

obtaining and retaining market share









SAFETY SYSTEMS AND HUMAN PERFORMANCE

IN MAINTENANCE

Maintenance Error Management Systems

Safety Management SystemsUK CAA CAP 716

Transport Canada has SMS requirement

US FAA - intent for the future?



SAFETY

MANAGEMENTSYSTEMS




IN MAINTENANCE



LIMITATIONS OF HUMAN PERFORMANCE

Perception and Cognitive limitations

Physical limitations

PERFORMANCE LEVEL ERROR TYPE

Skill-based level Slips and lapsesRule-based level RB mistakes

Knowledge-based level KB errors




IN MAINTENANCE

Man errs as long as he strives.

Goethe



ERROR TYPE MAINTENANCE EXPERT

DATA ASSESSMENT

Skip a step 0.15 0.001

Skip a task 0.026 0.001Ignore a warning/caution 0.042 0.013

Intentionally deviate 0.042 0.32

Improperly remove/replace 0.033 0.02

Improperly repair 0.089 0.0023

Incomplete installation 0.089 0.01

Improperly adjust 0.09 0.1 Allow/cause debris to enter 0.17 0.01




IN MAINTENANCE

Source Ostrom et al, INEEL



PROCEDURES MITIGATE RISK OF HUMAN ERROR

Clear documentation

Parts kitsChecklists

Inspections

Function checks

Even pre-flight checks




IN MAINTENANCE



EXAMINING THE RELATIONSHIP BETWEENBUSINESS RISK AND MAINTENANCE ERROR



MAINTENANCE ERROR AND BUSINESS RISK



…









Non- compliance is the norm in

many situations in daily life.

It is human nature to resolve

conflicts pragmatically.

Pragmatic solutions become‘Norms’.

Norms become ‘the way we do

things around here’.

Non - compliance becomes part

of the culture.

The non- compliance may

continue for years before the risk

emerges.






JUST CULTURE

Validity of the ‘Just’ culture rather than ‘blame’ or ‘no-

blame’.

SUBSTITUTION TEST

The substitution test – if another mechanic would have

done the same thing, then the issue is an… organisational problem.




BUT – there are hidden risks of rule-breaking…

If your organisation experiences rule-breaking, then it is

exposed to an unknown level of risk.

Dual risk –

1 the risk that the rule was intended to prevent:

(when we break the rule, we do not know the extent

of our exposure)

2 The risk of being caught out.

(Fines, litigation, Insurers deny claims)



Unexpected consequences!

‘XXX’ was the mechanic who fitted a non-standard

titanium strip to a DC-10...

‘He allegedly fixed the titanium alloy part instead of a

softer metal strip in the maintenance unit in Houston,

Texas, even though its use was not sanctioned by UScivil aviation authorities.

‘His supervisor was questioned in June by the judge but

has thus far not been put under criminal investigation.

‘The airline itself was placed under investigation formanslaughter and injuries in March, but has vowed to

fight any charges that may ensue’.




In 1994 AAIB stated: ‘The Civil Aviation Authority shouldformally 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 availablechannels 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.




THANK YOU FOR YOUR ATTENTION


airline safety and effects of maintainence alan simmons

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