1. MAINTENANCE ERROR ACCIDENTSBy
Wg Cdr (Retd) M U Khan, VSM
Deputy General Manager (Flight Testing)
Hindustan Aeronautics Ltd

2. Maintenance Error Accidents
Maintenance is :
Essential & Integral part of aviation industry.
Thus
Maintenance errors are likely to occur just like the flight crew related errors.
Aim is to:
Minimise the risk of maintenance related accidents / incidents

3. Content
Statistics of Indian Civil Helicopter Accidents due to Maintenance reasons
Contributory factors towards maintenance errors
Man
Machine
Environment
New Safety Requirements
Preventive and Predictive Maintenance
Future Trends

4. Year Wise Statistics of Accidents (1990-2005)
Total Maintenance

5. Statistics of Accidents (1990-2005)
PILOT ERROR
57%
MAINTENANCE
28%
GROUND ACCIDENT
10%
OTHERS 5%

6. Breakdown of Maintenance Related Accidents (1990-2005)
Improper Maintenance
40%
Technical Defects
60%
Fatal : 2
Injury : 1
Substantial Damage : 8
Total Loss : 3

7. Maintenance Issues TECHNICAL DEFECTS Fatigue Failure
IMPROPER MAINTENANCE
Incorrect Attachment
Incorrect Connection
Omission
Wrong part
Reversed Installation
Wrong Judgement
Improper tool/equipment
TECHNICAL DEFECTS
Fatigue Failure
Improper Manufacture
Incorrect Assembly
Internal Failures
Faulty Design
Faulty Mfg Process

8. Maintenance Errors - Factors
MAN
MACHINE ENVIRONMENT

9. Maintenance Errors ERRORS Oversight Attention lapses VIOLATIONS
Non-compliance of laid down instructions or regulations
- Someone in most maintenance departments make life or death decisions everyday.
- They determine if an aircraft is safe for flight or not.
- Most component technical issues in helicopters fall into shades of gray category
thus

10. THE INDIVIDUAL WHO MAKES SAFETY OF FLIGHT DECISION CAN’T MAKE MISTAKES
The maintenance personnel have a tough task to perform to keep the fleet airborne.
Their decision is easy if it’s a major safety of flight issue – ‘The aircraft is down’.
It is more difficult if it’s a minor discrepancy like metal chips in a transmission, a leaky actuator or minor cracks in secondary / tertiary structures.
All military & commercial aircraft fly with minor discrepancies.
THE INDIVIDUAL WHO MAKES SAFETY OF
FLIGHT DECISION CAN’T MAKE MISTAKES

11. Individuals usually realise their mistakes and rectify them.
However,
Not all errors lead to incidents / accidents.
Individuals usually realise their mistakes and rectify them.
Research has shown that people involved in critical professions routinely make small mistakes, which they detect and correct themselves.

12. Other Human Factors Lack of Communication Complacency Distraction
Lack of Knowledge
Lack of Teamwork
Fatigue
Lack of Assertiveness
Stress
Lack of Resources
Pressure

13. Environmental Aspects
Mostly all maintenance activities take place by night in artificial lighting conditions.
Hangars & Tarmac may not be always available at all times for maintenance operations.
Heat, Dust, Rain etc can be source of initiation of maintenance related incidents / accidents.

14. Errors due to the Machine
The helicopter is a very complex machine as compared to its fixed wing counterpart.
It operates in adverse environment such as dusty and salt laden atmosphere as well as close to ground. Thus making it maintenance intensive.
Present concept is to make the design for near Zero routine maintenance for short terms and ‘inspect & replace’ for the longer term maintenance cycles.

15. Avoid Maintenance Errors thru Design
Design features known to be a source of human errors are eliminated
Software logic to prevent errors
H U M S (Health & Usage Monitoring system)
I E T M S (Interactive Electronic Technical Manuals)
Onboard Diagnostics

17. Preventive Vs Predictive Maintenance
Maintenance professionals emphasize prevention as an inexpensive method of controlling maintenance costs and ensuring safety.
Technology has now advanced to such a point that a new trend has emerged – Predictive Maintenance.
But the two are not mutually exclusive.
An operator who has adopted both approaches is unlikely to get an unwelcome surprise from maintenance problems.
However the future is towards predictive maintenance.

18. Future Trends in Maintenance
Onboard diagnostic systems to not only record but also to analyse the data during the flight.
Possibly relay the same to the maintenance agency to ensure ‘just in time’ deliveries of replacement parts rather than stockpiling them.
Nanotechnology.
Smart materials.
Virtual Retinal Display.

19. Conclusion
The human aspect of the maintenance personnel is the most important area and needs careful attention by both – the operator and the regulator.
The environment plays a major role in ensuring proper maintenance of our helicopters and thus requires careful attention.
Modern technologies can aid reduction in maintenance error accidents.