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RAeS HFG EMSG Compliance in Maintenance Project

Royal Aeronautical Society (RAeS),

Human Factors Committee (HFG)

Engineering and Maintenance Standing Group (EMSG)

Safety Culture in Aviation Maintenance.

Non-Compliance with Maintenance Procedures

1.Introduction and Background

Aircraft maintenance within public transport operations is subject to many challenges, typically these include: time constraints, cost constraints, competition, staffing, training, management of technical data and required resources. One of the key issues affecting safety in aviation maintenance was considered by the EMSG to be the “Safety Culture” that exists in a company. Corporate culture is a potentially huge topic, involving many contributing elements. A culture of compliance is one that supports an organisation’s safety achievement to desired levels; conversely one of non-compliance is one that threatens it, in particular the potential for human error to occur.

One of the key elements identified by the EMSG through maintenance error investigation as a causal factor is the apparent level of non-compliance with maintenance procedures and their usability. Maintenance procedures in themselves are also a vast topic, which would require a very complex study, and larger than the EMSG had the resources to support. Therefore, to try to get a better understanding of the extent that non-compliance affects safety the committee decided to study compliance with one particular aspect of inspection, using the first level inspection as a baseline example.

The ‘Daily’ check was chosen for study being a check typically carried out every 24 to 48 hours. It is also the first level of inspection that requires a release to service. Committee members considered that there was no obvious recorded safety issue highlighted from the accomplishment of Daily checks, therefore the level of compliance might shed some light on the decision making process of maintenance personnel when carrying out inspections. The Daily check had additional value, as it’s a manageable chunk of maintenance activity suitable for this kind of study. This microcosm of the maintenance workplace might address some of the issues surrounding compliance and whether the decision making process was linked to whether an item of work is feasible, practical or indeed perceived to be warranted. The selection of tasks for compliance or otherwise should not be a decision for the maintenance engineer but it is clear that they frequently have to make such decisions.

If reasons for non-compliance with procedures can be reduced, better managed, or even eliminated, it would strengthen the case for compliance with good, workable procedures. This in turn, should promote better safety practices in the organisation and improve the company’s safety culture. We strongly believe it is important to stop bad norms that we believe already exist and/or are developing.

2.Aims

The studies primary aims were considered to be:

• To determine the nature and extent of compliance with procedures within Daily inspections.
• To understand the maintenance engineer decision-making process where compliance or non-compliance was achieved and to understand if this was random or systematic within shifts, the Company or more widely in the aviation industry.
• To improve the management of compliant practice in aviation maintenance organisations.

In the generation of this report, there was no intention to show licensed engineers as being irresponsible or deliberate rule breakers. Nor was the intention to suggest that the answer to the problem is simply to enforce dogged compliance with every procedure, as they currently exist. It was however, the aim to raise the profile of a perceived problemwithin the maintenance environment. To take the opportunity to express the concerns that many have within the industry regarding the problemsmaintenance engineers face. They are faced with balancing the multiple pressures in aircraft maintenance today, whilsttrying to maintaincomplex systems in aircraft,with limited resources.

3.Methodology

To determine the degree of compliance with Daily inspection, procedures in several UK maintenance organisations were reviewed. EMSG committee members, who were employees of the respective airlines, achieved this within their own organisations. EMSG members looked at examples of compliance with Daily checks within their own organisations using a process of unobtrusive observation similar to that used in Line Oriented Safety Assessment (LOSA) assessments. This was carried out as an independent overview of the task, without interference, although we also sought feedback from those engineers doing the task. The results were pooled to de-identify the organisations involved. It is also a fact that inevitably some of the findings are more supported by opinion than fact, but that does not detract from the information contained herein.

4.General Findings

The review of compliance with the “Daily” inspection followed a standard methodology of observation and discussion of those who routinely do the task

• All of the organisations contributing were operating large commercial airliners in scheduled, or chartered public transport operations.
• Each airline had documented checklists available for their staff to use when carrying out the Daily inspection.
• Each checklist was based on the aircraft manufacturers maintenance recommendations, but had been enhanced by the airline based on their operational knowledge to add to the requirement of the “Daily”.
• Although checklists were available in most cases the experienced engineers carrying out the dailies task did not see the need to use them.
• The engineers observed in this review were considered to be average, or better experienced people who were well trained, capable and importantly committed to the task of safety within aircraft engineering and their Company’s thrust for safe operations.
• None of the observed inspections and the associated actions resulted in any negative safety outcomes.

5.Indicative Findings

Although not necessarily the same in all companies, or even between individual Engineers, the following listed findings are indicative of the maintenance environment we currently operate within, and to better understand the working environment it was necessary to record some generalisations and assumptions. Also a number of common themes were identified, which suggest “norms” in the aviation maintenance industry within the UK and potentially exactly the same issues exist many other countries.

• Generally is was advised that the engineers would look at the checklist from time to time as a refresher, but it was suggested that the routine use of the checklist was only necessary whilst experience was built on a given aircraft type.
• There was virtually no systematic quality assurance assessment of the Daily Inspection and how it was achieved. Albeit, all, or part, of the “Daily inspection” could be assessed during the routine quality processes in place.
• Compliance audits called for in EASA Part 145-A-6(c), were often not effectively carried out, and in any case, compliance with the requirements of a “Daily” was not seen as key target for such checks.
• The engineers routinely made judgements of what not to cover in the “Daily” based on their individual experiences, but this did not follow a systematic decision making process.
• Whenever the engineers undertook non-standard actions, they did so with the best intentions, they believed they were meeting their Company’s needs. The engineers, being practical, when dealing with the day-to-day adversities tend to think more about the task and its completion and not the level of compliance. However, they do recognise risks and do not deliberately take what they perceive to be risks to get the job done.
• The amount of detail covered in the “Daily” could vary, this was largely said to be dependant on secondary tasking for the engineer on the shift. This additional tasking included the amount of defect rectification that the engineer might be required to support on the aircraft, or the numbers of certifying staff available on the shift to complete the work.

There were notable variations from the intended requirements; the findings for these and our views on the relative risks are reported in the detailed analysis below.

6.Analysis of Specific Elements

Each element of the Daily was reviewed and of these those with observed variance or concerns have been identified, commented on, and assessed herein. Herein, each task element is commented on and assessed for impact. The observations are based on the notes taken from the task assessors, and the comments are views of EMSG members that relate to the task element.

Task Element / Observed Standard / Potential Risk Level
6.1Flight deck checks / Variable / Low

Observations:

Generally the high level of achievement is commensurate with the perceived importance. The working environment is comfortable and the tasking varied and in some part interesting. When necessary, handy kits are available e.g. filaments.

In some cases, the cockpit checks were not done to an effective standard, maintenance staff citing two primary reasons.

-The ability to access the flight deck readily, particularly if the aircraft is on a turn-round, and

-Many tasks are duplicated and done by both the flight crew and engineers. Defects were considered likely to be reported as and when they were identified, (e.g. fire system squib tests) therefore it is perceived that this is not a strong driver for the engineer to carry out these checks.

Cockpit checks appear to be an area where the engineer’s workload might be reduced. Particularly if there was not enough time to do everything without incurring technical delays.

EMSG Comments:

Although assessed as low risk some issues such as flight management and auto pilot functionality might not be discovered until the aircraft is airborne if the designated checks are not carried out during the Daily inspection.

Task Element / Observed Standard / Potential Risk Level
6.2Wheels, Tyre & Brake checks / Good / Medium

Observations:

Tyre checks were generally done to a high standard. Tyre checks were viewed as fundamental, and appeared to be done as a matter of course. These checks were usually the first thing looked at on arrival and are easy to access. It was also understood that tyres are susceptible to damage during landing and taxiing and therefore need to be routinely checked, this was reasonably systematic across all the companies maintenance departments. Issues like checking the tyre pressure and especially where fairly low readings in the acceptable band had been noted on previous sectors meant that tyres are almost always checked. However, it was noted that there was an element of sampling and as a negative; in poor weather this tasking was not as well achieved.

Some checks such as the wheel brake check were noted as being done as a visual check with brake off, which was not in accordance with the requirements, but the engineers claimed that they could tell the wear status just as well in this way, and although it is non-compliant, it is seen to work.

EMSG Comments:

Medium risk, shortfalls in checking tyres and tyre pressures could result in high profile delays if the crew refused to accept it, or the aircraft suffered a puncture during taxiing, or take-off runs.

Similarly brake condition checks could lead to serious implications of overruns if not done correctly, but this was not seen as having the same level of importance in risk terms, although clearly that is not necessarily the case.

Task Element / Observed Standard / Potential Risk Level
6.3Engine checks / Good / High

Observations:

All engineers considered engine checks as critical hence a high level of compliance. Primary areas considered were FOD damage through the engine, oil levels and fuel or oil leaks.

Recording oil uplifts was not systematic.

EMSG Comments:

Potentially this can be high risk, especially if checks are not done, but this is well understood, and no evidence of poor compliance was noted.

Task Element / Observed Standard / Potential Risk Level
6.4Visual external checks / Variable / Medium

Observations:

Most exterior checks are done in a general sense as part of the walk-around, but although the engineers are trained to be observant, this task lacks a clear focus. There are some known no-go items and these were seen to be systematically checked (e.g. jiffy drain leaks, dry bay leaks etc.) the biggest problem, in particular on very large aircraft, is accessibility, exacerbated by the fact that not all areas can be clearly seen from the ground.

Tasks, such as checking cowlings etc. can be highly variable, some doing a general check, whereas others carry out more specific checks of particular areas e.g. engine clamshell doors. The working environment is not good in winter months, especially in bad weather, the tasking in these areas can be dirty (e.g. in wheel-wells etc.) and visibility can also be poor.

Checks of the external lights had a low level of compliance because it was reasoned that the filaments can fail at any time. It was also proposed that some engineers might do the exterior light checks by observation as the aircraft taxied-in.

One problem that is particularly relevant to exterior area inspections is the order in which the checklists call off the items to be inspected, they tend to order these by ATA chapter rather that to reflect the flow of work as the engineer moves around the aircraft.

EMSG Comments:

The risk is medium, as the walk round for the exterior areas is a general visual for structural damage and integrity.

The effective completion of external checks is an area where non-compliant methodologies can be commonplace and at the same time remain undetected or indeed unlikely to raise concerns with the supervisors or managers as it would be seen as implementing a logical workflow, this might not be their view if an incident occurs.

The practice of non-systematic checks is a potential problem that warrants effective company and regulatory control.

Task Element / Observed Standard / Potential Risk Level
6.5Cargo hold checks / Variable / Medium

Observations:

In many cases little is achieved in the way of inspection in the cargo bay areas, this is often not seen by the engineers as an area of significant risk and the area is very busy in the periods prior to or after any flight with luggage and freight handling underway, which makes access a problem. Also it may be assumed that the loadmaster and his team will report any problems they notice, but this is not a viable practice.

Although the integrity of the cargo doors and surrounding areas is demonstrably important and has been causal in several high profile accidents and incidents, in some cases there was little concern shown for this area during inspections being undertaken.

EMSG Comments:

The risk is medium to high, again an area where structural damage to the airframe, cargo doors, and fire integrity of the baggage hold side walls and door frames, seals etc are critical to the aircraft, but are not seen as an area of high concern by the maintenance staff.

Task Element / Observed Standard / Potential Risk Level
6.6Fuel/water checks / Poor / Low

Observations:

The quality of modern jet fuel and the standards in place in general within the oil companies providing the fuel results in only a minimal number problems occurring. Whilst this is a positive situation, its potential benefit is eroded by a lack of available downtime to do the task correctly, which is rarely available and in the absence of problems, not doing these checksbecomes a norm amongst engineers that water/contamination checks, as part of the Daily inspection, are largely unnecessary. It is not considered viable in the real world to consider delaying an aircraft to allow time for settling after refuelling before doing the water drain check.

Feedback received was based around the high reliability of the aircraft and the fuel provided. Whereas, the problem relates to the quality of fuel uplifted, and the ability of the fuel in the aircraft to condense water held in the fuel in suspension and to condense moisture out of the air.

It was further reported that engineers had found that one particular manufacturer’s aircraft was more prone to water build up in the fuel cells than in other types, and in these cases the fuel drain sample checks were more likely to be done.

Secondary in the concern, but none-the-less significant if allowed to develop, is fungicidal contamination of the fuel system typically Cladosporium Resinae. Fungicidal contamination can be particularly prevalent where water settles in fuel tanks and allowed to stay there.

EMSG Comments:

The risk is low - purely due to the high levels of reliability of the fuel at the point of delivery. The widely held belief that water drain checks are unnecessary, but this is fundamentally erroneous however, the low incidence of problems perpetuates it.

Task Element / Observed Standard / Potential Risk Level
6.7Cabin checks / Poor / Low/Medium

Observations:

Minimal checking is done in the cabin, time and accessibility is the primary reason given. The checking of items such as: seat serviceability and availability of a serviceable life jacket per seat were seen as not being feasible, or even reasonable to expect this to be done on large aircraft, and at best some sampling is done. As part of checking the aircraft cabin some elements are virtually never done, typically the engineers do not often check cabin lights, albeit that they do rectify any reported defects in the cabin as required.