Final Dissertation

Improvements in dismantling and recycling of commercial

aircraft

A research project submitted to The University of Manchester for the degree of MEng Aerospace

Engineering with Management by

Gamuchirai Hogwe

9247094

2016

The School of Mechanical, Aerospace and Civil Engineering

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CONTENTS 1. INTRODUCTION ................................................................................................. 4

1.1 Background .................................................................................................... 4 1.2 Scope ............................................................................................................. 5 1.3 Rationale ........................................................................................................ 6 1.4 Aims and objectives ....................................................................................... 6 1.5 Importance of aircraft dismantling and recycling ............................................. 7 1.6 Methodology ................................................................................................... 8

2. LITERATURE REVIEW ....................................................................................... 9

2.1 Introduction .................................................................................................... 9 2.2 Aircraft lifespan .............................................................................................10 2.3 Aircraft materials ...........................................................................................14

2.3.1 Carbon composites in aviation ................................................................16

2.4 Management in aircraft end-of-life .................................................................19 2.5 Comparison with other industries ..................................................................20 2.6 Ecological hierarchy ......................................................................................21

3. CURRENT HANDLING IN EOL PHASE .............................................................23

3.1 Decontamination ...........................................................................................24 3.2 Disassembly ..................................................................................................25 3.3 Dismantling, recycling and component management .....................................25

3.3.1 Re-use of recycled aluminium alloys .......................................................26

3.3.2 Cabin interiors .........................................................................................27

4. CASE STUDIES .................................................................................................29

4.1 The AFRA initiative ........................................................................................29 4.1.1 Aims and Objectives ...............................................................................30

4.1.2 Operations ..............................................................................................30

4.1.3 Results ....................................................................................................31

4.2 PAMELA .......................................................................................................32 4.2.1 Introduction .............................................................................................32

4.2.2 Aims and Objectives ...............................................................................32

4.2.3 Funding ...................................................................................................33

4.2.4 Operations ..............................................................................................33

4.2.5 Results ....................................................................................................33

5. SORTING TECHNIQUES ...................................................................................34

5.1 Eddy current separation ................................................................................34 5.2 Magnetic sorting ............................................................................................34 5.3 Air sorting ......................................................................................................35 5.4 Laser induced breakdown spectroscopy ........................................................35 5.5 Hoopes process ............................................................................................36 5.6 Low temperature electrolysis .........................................................................36

6. RECYCLING CARBON COMPOSITES ..............................................................36

7. DISCUSSION .....................................................................................................39

7.1 Challenges in dismantling and recycling ........................................................39 7.2 Maximising value recovery ............................................................................41 7.3 Recommendations ........................................................................................41 7.4 Conclusion ....................................................................................................42 7.5 Future Work ..................................................................................................43

8. References .........................................................................................................44

Appendix ................................................................................................................47

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List of figures

Figure 1 - Value of aircraft as a function of age

Figure 2 - U.S. Domestic air travel, 1980-2003

Figure 3 - Survival of fleets as a percentage of deliveries

Figure 4 - Summary of the alloys that constitute the 737

Figure 5 - Percentage of alloying elements in different aluminium alloys

Figure 6 - Materials used in the 737 body

Figure 7 - Market share of composite materials

Figure 8 - Carbon composite revenue in US$ million in Aerospace and

Defence by sub segment

Figure 9 - Materials used in the 787 body

Figure 10 - Ecological hierarchy adapted to EOL aircraft

Figure 11 - Composition of the recycled aluminium

Figure 12 - AFRA Founding members

Figure 13- The layered structure of the 787 composite

Table of Abbreviations and Acronyms

Meaning

EOL End-of-life

EU European Union

AFRA Aircraft Fleet Recycling Association

PAMELA Process for Advanced Management of End-of-Life Aircraft

OEM Original Equipment Manufacturer

CFRP Carbon Fibre Reinforced Plastics

EASA European Aviation Safety Agency

ELV End-of-Life Vehicle

REACH Registration, Evaluation, Authorisation and Restriction of Chemicals

RoHS Restriction of the use of Hazardous Substances

ARN Auto Recycling Netherlands

LIBS Laser Induced Breakdown Spectroscopy

ICAO International Civil Aviation Organisation

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ABSTRACT

Increasing environmental concerns and hiking fuel prices mean that aircraft

owners are looking to own aircraft with lowest possible fuel consumption. As

such, aircraft design is constantly evolving, particularly materials used. This

change in materials further complicates the problem of how aircraft in the

end-of-life phase should be treated. A few dismantling and recycling

techniques exist at present but they are not optimal for environmental

conservation and value recovery. This project studies these existing methods

and suggests ways in which they can be improved. The problems in

aluminium recycling and the treatment of cabin interiors are addressed and

potential solutions for these problems suggested. The use of carbon

composites in aircraft manufacture will also be studied to develop sustainable

end-of-life management of the composites and the aircraft as a whole.

Acknowledgements

The author would like to thank Mr Timothy Jones for his support throughout

the duration of the project. The author also wishes to thank family and friends

who provided their support during the writing of this report.

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1. INTRODUCTION

1.1 Background

In the 2013-2032 Airbus global market forecast, it is estimated that 8939

passenger aircraft will retire and Boeing’s current market outlook for the

same period predicts this figure to be 14580.

Van Heerden & Curran (2010) define an end-of-life aircraft as one that is

considered old and (almost) obsolete. There is an increasing need to reclaim

these aircraft in ways which are environmentally responsible while retaining

some of their value. However commercial aircraft are changing with

increasing environmental concerns and fuel prices. By trying to identify and

understand these changes, this project aims to set out ways in which these

challenges can be overcome, thereby improving the overall end-of-life

management of an aircraft, particularly its dismantling and recycling.

At the first instance, it is not hard to conclude how percentage change in

material types and their composition will greatly affect the processing

techniques and infrastructure required to separate and recycle parts of

obsolete aircraft effectively. This essentially makes the processing of end of

life aircraft a dynamic problem. Knowing what changes and how it changes

gives a better understanding of the challenges faced in the end-of-life phase

of an aircraft and how best to accommodate the dynamic nature of this

problem. This will sometimes be referred to as the end-of-life problem in this

report.

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1.2 Scope

The report endeavours to cover not only the technical specifics associated

with the recycling management of end-of-life aircraft, but to also consider a

strategic approach to value recovery from these aircraft. A study of existing

problems in the end-of-life management of aircraft will be carried out. This

will encompass current management of traditional aircraft material and how

this can be improved.

Furthermore, the scope of this project will also cover the materials of aircraft

models, study the difference between them and how this affects the end-of-

life phase of the aircraft. Two specific models will be used as examples in this

study, namely the Boeing 737 and the Boeing 787. The 737 represents the

older aircraft, made mostly of aluminium, which are currently coming out of

service. On the other hand, the 787 represents more modern, recent aircraft

containing a high percentage of carbon composites. The project studies the

changes in composition of commercial aircraft and the challenges these

changes create at the end of the aircraft’s life. The author hopes to give

solutions to the problems posed by the changing materials and suggest ways

in which dismantling and recycling can be improved.

The study will give little consideration to the recycling of material in aircraft

engines and focus more on the rest of the airframe. This is because of

increasing popularity of engine leasing in commercial aviation which means

engines are usually returned to the manufacturer at the aircraft’s end-of-life.

(Davies, 2015) As such, they will not usually constitute the end-of-life

problem for aircraft owners.

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1.3 Rationale

The air transport industry continues to grow as population grows and the

economy evolves. An increase in international trade and tourism also

generates a market for long distance travel. Air traffic results for the year

2015 have shown a 6.5% increase in the demand for air transport from 2014.

(IATA, 2016) As such, the ecological footprint of the industry will continue to

increase. It is imperative that the aviation sector increases its efforts to

reduce its ecological footprint.

There is already a problem in the aviation industry concerning how end-of-life

aircraft should be treated and this problem is made even bigger by the

introduction of new materials into the process. In order to encourage efficient

dismantling and recycling of aircraft, the processes should be economically

attractive, in order to attract investors to this industry. (Siles, 2011)

The project choice and its scope are driven by the need for solutions to the

end-of-life problem which are beneficial to both the environment and to

economy. This information will not only be useful to manufacturers in their

future designs, but will also be useful to aircraft owners as they will be able to

extract as much value as possible from their end-of-life aircraft. Governments

can also use this information to decide what environmental legislations they

will put in place in the aviation industry.

1.4 Aims and objectives

This project aims to suggest ways in which the aircraft end-of-life problem

can be addressed. The aim is to achieve a system of end-of-life management

which is both environmentally friendly and economically viable.

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The objectives of this project are:

Studying the challenges that industry currently faces with respect to

aircraft dismantling and recycling

Suggesting ways in which these challenges can be overcome in order

to improve the entire process

Addressing the use of composites in aircraft and suggest ways in

which these composites can be recycled at the end of an aircraft’s life

Investigating tooling, technology, personal and environmental

protection involved in the overall process of dismantling and recycling

and suggesting ways in which they can be improved.

Finding ways in which value can be recovered from aircraft cabin

interiors

1.5 Importance of aircraft dismantling and recycling

Leaving planes parked in boneyards (aircraft graveyards) is not only an

environmental risk but also risks unregulated dismantling of aircraft and

illegal resale of parts on the black market. Parts without proper tracking and

certification are very dangerous, especially in a sector like aviation where

safety concerns are very significant. This shows the importance of recycling

aircraft through legitimate channels.

Aircraft owners should consider the cost of storing aircraft in boneyards.

Depending on aircraft size, monthly fees for parking aircraft can range

between $2500-$3000 (£1731-£2000). (de Brito, et al., 2007) These are

expenses that can be avoided if the aircraft is recycled.

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From governments’ perspective, it is beneficial to develop technologies in

dismantling and recycling of aircraft, as this will open an industry that will

provide sustainable job opportunities. Furthermore, recycling of aircraft will

reduce the adverse impact that the aviation industry has on the environment.

1.6 Methodology

This section describes the methods that the author employed during the

course of this project.

This project is management based; hence the entire project is based on

literature review and an intensive study of the commercial aircraft industry. It

is worth noting that limited work has been done in the field of aircraft

dismantling and recycling, hence academic literature on the topic is quite

limited. This provided a challenge in finding sufficient accurate data to aid

with an analysis. A lot of the information has been collected from news,

technical reports, dissertations, company websites and journals. During the

completion of the literature review, the author has collected a lot of

information relevant to aircraft dismantling and recycling. Research into

aircraft manufacturers, their websites and their market projections has also

been helpful to the author. It is hoped that from this text the author will be

achieve a better understanding of all relevant concepts.

The author has selected Boeing aircraft to be the focus of the study because

the manufacturer has been in operation for a much longer time than its top

competitor, Airbus. This provides the author with a broader timeline through

which to study the evolution of aircraft materials and their recycling methods.

Consequently, the two types of Boeing aircraft are chosen on the basis of

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when they were first manufactured. The difference in time between these two

dates (1968 for the 737 and 2009 for the 787) allows for a significant change

in manufacturing principles, hence facilitating an in-depth study of the

changing compositions of materials.

Furthermore, the use of case studies was used in order to give the author a

better understanding of the end-of-life management of aircraft. The case

studies carried out are of the AFRA initiative and the PAMELA-LIFE project.

The case studies give an outlook on current practices, which in turn will help

the author to make any improvement suggestions.

Since data used for this report is secondary, it is useful to mention that a

certain level of bias may be contained in some sources reviewed by the

author. This stems from the theoretical nature of the topic; there aren’t many

experiments that back up the facts and a considerable amount of them are

from other authors’ opinions. In order to reduce this bias, the author has read

several sources on each concept, to get as many perspectives as possible

on each one.

Information from this study will be used to suggest ways in which the end of

life phase of aircraft can be improved.

2. LITERATURE REVIEW

2.1 Introduction

For decades, defunct aircraft have been parked in aircraft graveyards

(boneyards) despite the increasing demand for recycled aluminium, among

other materials. Most boneyards are located in the desert, where the dry heat

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facilitates minimal rusting of the aircraft. In August 2009, 17.8% of aircraft

(4691 to be exact) were listed as parked globally. (Van Heerden & Curran,

2010) Parked aircraft may go back to active service, but most of them are

already in end of life status and they will never fly again.

In the aviation industry, pressure to involve in environmental efforts mainly

stems from competitive forces and customer pressure. As landfills close and

population continues to grow, waste management is becoming more and

more crucial. (Pohlen & Farris, 1992)

2.2 Aircraft lifespan

The two main causes of aircraft retirement are mechanical obsolescence and

economic obsolescence. Market conditions as well as the condition of the

aircraft itself determine whether an aircraft will remain in service. With time,

aircraft value depreciates as the cost of maintenance and repair increases.

The older the aircraft is, the more often it will require unscheduled

maintenance, and thus maintenance cost increases. For example,

maintenance of an aircraft in operation for 30 years will cost at least double

what it cost when the aircraft was 5 years old. (de Brito, et al., 2007) The

variable costs (include fuel, airframe maintenance, engine restoration etc.)

associated with maintaining a Boeing 737-200 are estimated at $8917

(£5929.84) per month. On the other hand, the maintenance costs of a newer

variation of the 737, the 737-600 are estimated at $6631 (£4409.20). (Anon.,

2015) This difference in cost can justify why an aircraft operator would want

to take the older aircraft out of service. This would fall under the aircraft’s

economic lifespan. The economic life of a plane depends on factors such as

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the operator’s business model, fleet planning, local economic factors and

acquisition timing. (Jiang, 2013) Figure 1 below shows the typical

depreciation in value of an airframe with time. The index on the vertical axis

represents aircraft value.

Figure 1: Value of aircraft as a function of age (Towle, 2007)

In addition to this, reduced fuel consumption and customer satisfaction are

other factors that determine that aircraft should go out of operation. (Mascle,

et al., 2013) Several factors may affect air travel, such as economic

recessions, terrorist attacks and increases in oil prices. All these things can

reduce the volume of air travellers, hence shrinking airlines’ market. When

business goes down for an airline, it may not be profitable to keep its entire

fleet in operation; hence some aircraft are forced to retire early. Figure 2

below shows trends in U.S air travel from January 1990 to December 2003.

(The graph has been rotated to aid visibility) The y-axis shows the domestic

revenue passenger miles in the U.S with time in years on the x-axis. The red

line indicates a 12-Month moving average.

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Figure 2: U.S. Domestic air travel, 1980-2003 (Ito & Lee, 2005) As can be seen from the graph, there was a drop in air travel following the

1981 Air Traffic Controller’s Strike, the 1991 Gulf War and an even larger

drop following the September 11 terrorist attacks. 298 aircraft were parked in

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the U.S during the period until December 2002, with US Airways parking

eight Boeing 737s and American Airlines parking five Boeing 767 in

November 2002. (Kumar, et al., n.d.)

It is difficult to quantify the lifespan of an aircraft because it depends on a lot

of different factors, but Boeing has found it to average more than 15 years in

most planes. (Jiang, 2013) Average survival curves for major single-aisle

passenger aircraft is illustrated in Figure 3 below. Average fleet age is

represented in the x-axis while the y-axis shows surviving fleet as a

percentage of total deliveries.

Figure 3: Survival of fleets as a percentage of deliveries (Jiang, 2013)

It can be seen from the graph that the lifespan of aircraft is quite variable. It

can be noted that the survival curves for the 707 follows a slightly different

trend from the later models. it can be deduced from this difference that

technological advances have impacted aircraft’s economic life.

Structure is an important factor that determines the lifetime of an aircraft.

Pressurisation cycles in particular affect the aircraft’s lifespan. During each

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flight aircraft is pressurized and hence experiences fatigue. Inspection during

service life can detect defects that develop in the airframe.

2.3 Aircraft materials

The aviation industry contributes 2% to global man-made carbon emissions.

(ICAO, 2013) As such, manufacturers are constantly under pressure to

evolve their designs in order to increase aircraft’s fuel efficiency. Changing

the material composition is one of the main design methods that the

manufacturers are employing.

Aircraft manufacture makes use of materials ranging from low cost interior

materials to high performance alloys and composites. Aluminium alloys are

most commonly used in aircraft manufacture. They are typically produced in

the form of high-strength, low-density sheets by wrought processes. In

general, alloys used in aircraft fall into two categories, the 2XXX series and

the 7XXX series. Stainless steels, nickel, copper and titanium are also major

components used in aircraft manufacture. More often than not, aircraft alloys

contain grain-refining elements like Chromium, Zirconium and Vanadium in

small quantities of approximately 0.1% (or less). (Das & Kaufman, 2007) In

the older models, aluminium is the major material while composites are

becoming more prevalent in the newer models. (Mascle, et al., 2013)

The Boeing 737 was first produced in 1966. As of March 2016, a total of

8845 deliveries of 737’s had been made. (Brady, 2016a) Boeing has

delivered several variations of the 737. The 737-200 entered service in April

1968. Production of this particular variation has stopped but 1114 were built.

The aircraft is made mostly of aluminium alloys. Different areas of the aircraft

15

use different types of alloys depending on the material characteristics

required. For example, landing gear beams would require a very tough alloy

with a very high tensile strength. Below is a table (Figure 4) which

summarises the aluminium alloys that make up the 737-200.

Component Aluminium Alloy

Fuselage skin, slats, flaps 2024

Frames, stringers, keel and door beams, wing ribs 7075

Bulkheads, window frames, landing gear beam 7079

Wing upper skin, spars and beams 7178

Landing gear beam 7175

Wing lower skin 7055

Figure 4: Summary of the alloys that constitute the 737 (Brady, 2016b)

The different alloys listed in Figure 4 above each have different compositions,

which are shown below in Figure 5.

Elements

Alloy Zn Mg Cu Mn Cr Fe Si

2024 - 1.5 4.4 0.6 - 0.5* 0.5*

7055 8.0 2.05 2.3 - - 0.15* 0.1*

7075 5.6 2.5 1.6 - 0.23 0.4* 0.4*

7079 4.3 3.2 0.6 0.2 0.15 0.4* 0.4*

7178 6.8 2.8 2.0 - 0.23 0.5* 0.4*

7175 5.6 2.5 1.6 0.1 0.2 0.2* 0.15*

Figure 5: Percentage of alloying elements in different aluminium alloys

(Starke & Staley, 1996)

There are components that are not made out of aluminium alloys. The

radome, tail cone, centre and outboard flap track fairings are made of

fiberglass. The engine fan cowls, inboard track fairing, nose gear and doors

are Kevlar. Graphite is used to make the rudder, elevators, ailerons, and

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spoilers, thrust reverser cowls and the dorsal of vertical stab. Figure 6 below

gives a summary of the percentages of the materials in the 737.

Figure 6: Materials used in the 737 body (adapted from Lee, et al., 2010)

2.3.1 Carbon composites in aviation

The use of composites allows the physical properties to be tailored to

different applications by combining characteristics of the different constituent

materials. The aerospace industry is one of the largest markets for

composites, with 20% of composite applications being in this sector. (Yang,

et al., 2012) Figure 7 below shows a breakdown of composite materials in the

European market.

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Figure 7: Market share of composite materials (Yang, et al., 2012)

Furthermore, commercial aircraft provide the largest market for composites

within the aerospace industry. 60% of the revenue generated in aerospace

from composites is in the commercial aircraft segment, as illustrated in Figure

8 below.

Figure 8: Carbon composite revenue in US$ million in Aerospace and Defence by sub segment (Holmes, 2014)

The use of composite materials in aerospace is only expected to increase,

since they may allow a weight reduction of 40-60% in the aircraft. (Ye, et al.,

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2005) Carbon Fibre Reinforced Plastics (CFRP) are the predominant types

used in aerospace applications.

Despite the benefits that come with the use of composites, industry’s ability

to recycle carbon fibre materials is still very constrained. However, with all

the composite use in aerospace, aircraft owners cannot continue to send

their waste composites to landfill as this is a serious environmental hazard.

Another downside to the use of carbon fibre in reinforcement is it costs an

estimated ten times more than using glass fibre instead. (Gosau, et al., 2006)

The cost of manufacturing virgin carbon fibre is between £10 and £20 ($15-

$30 per pound of material and the energy consumption is between 25 and

75kWH. (Yang, et al., 2012).

50% of the 787’s airframe and primary structure is made out of advanced

composites, and this percentage is greater than that in any previous Boeing

commercial airplane. (Boeing, 2015) This move to a more composite

structure was not only meant to reduce weight, but was also expected to

reduce both scheduled and non-routine maintenance burden on airlines. The

decrease in scheduled maintenance stems from the fact that composites

have less risk of corrosion and fatigue in comparison with metal. Aluminium

makes up 20% of the airframe. Figure 9 below gives a pictorial

representation of materials used in the construction of the 787

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Figure 9: Materials used in the 787 body (modernairliners.com, 2015)

Boeing uses polymer-matrix composites in the 787, mainly an epoxy-matrix

which integrates carbon fibres. (Lu & Wang, 2010) The material employs a

thermoplastic toughener in an interlayer between the epoxy layers, giving it a

thick laminate structure. (McConnell, 2010)

2.4 Management in aircraft end-of-life

There are several bodies and individuals who are involved in and affected by

the end-of-life management of aircraft. Aircraft manufacturers are major

stakeholders as their designs have a direct effect on the complexity of the

end-of-life problem. During initial design, manufacturers should consider what

will happen to the aircraft at the end of life because some complex designs

can reduce recyclability rate. (Asmatulu, et al., 2013) This is applicable as

well to other original equipment manufacturers (OEMs) involved in the supply

chain such as engine manufacturers. Airliners and aircraft owners also play a

big role in this industry. The management of their aircraft at the end-of-life

phase is of great importance as it has direct effects on not only their profits,

but their corporate social image.

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Governments are responsible for environmental protection and as such, can

pass regulations which dictate how end-of-lie aircraft will be treated.

Regulatory bodies such as EASA which specify safety requirements and

certify airworthiness of aircraft can also determine when an aircraft is taken

out of service. Aircraft dismantling and recycling companies are the obvious

stakeholders in this sectors in this sector.

Cost factors involved in the end-of-life phase of an aircraft are transportation

costs, cost of skilled workers, investment in innovative technologies, time and

required databases. (Keivanpour, 2015)

2.5 Comparison with other industries

This section outlines the end-of-life management in different sectors,

particularly the automotive industry. This is meant to illustrate that the

aviation sector is lagging behind with respect to recycling and the end-of-life

management of its products. Different industries have put directives in place

for the environmentally friendly end-of-life management of their products. In

Europe, the End-of-Life Vehicle Directive and the Waste Electrical and

Electronic Equipment legislations aim to improve how industries deal with the

waste they produce, with the former being for cars and the latter for domestic

household appliances. In aviation, however there is no such legislation and

aircraft owners and manufacturers do not have any regulations on how to

design or deal with their end-of-life aircraft, particularly how to design an

aircraft that meets legitimate end-of-life requirements. (Van Heerden &

Curran, 2010) The ELV legislation was introduced in 2000 in Europe.

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In the EU, about 11.3million vehicles are deregistered each year and of

these, 7.6million are recycled. (de Brito, et al., 2007) In the Netherlands,

automotive recycling is financed by a dismantling fee which is charged to

every new car buyer. In 2007, this fee was €10 for each vehicle. (de Brito, et

al., 2007) The ARN (Auto Recycling Nederland) is the body in charge of end-

of-life vehicle recycling. According to ARN, 82% of a vehicle by weight is

recycled and 3% of it used in energy recovery. (de Brito, et al., 2007) In the

U.S., 95% of all automobiles at the end-of-life stage are likely to be recycled.

(Kumar & Sutherland, 2009)

A method has been determined by the International Standards Office (ISO) to

evaluate the performance of the recycling of automobiles and the efficiency

of the process. In this model, the reused components and recycled materials

are expressed as a percentage of the total vehicle’s mass in order to

calculate recyclability rates. They have not, however, defined a similar model

for measuring performance within the recycling of aircraft. (Van Heerden &

Curran, 2010)

2.6 Ecological hierarchy

This section analyses the possible options for management of end-of-life

aircraft. It analyses, from an environmental point of view, which options would

be better. It is worth noting that environmental best practice does not always

coincide with maximum value recovery. As such, aircraft owners often have

to make a trade-off between minimising their ecological footprint and

recovering some value from their end-of-life aircraft. The ecological hierarchy

is adapted from the ladder of Lansink, which specifies end-of-life activities

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according to their friendliness to the environment. Figure 10 below shows the

pathway that can be used to ensure the least damage is made to the

environment when dealing with end-of-life aircraft. Environmental friendliness

decreases from the left to the right hand side of the diagram. The sub-

categories have the most sustainable options at the top.

Decreasing environmental friendliness

Figure 10: Ecological hierarchy adapted to EOL aircraft (adapted from Van Heerden & Curran, 2010)

At the top of the hierarchy is the refurbishment and reuse of aircraft while

maintaining its same function. As seen from an end-of-life perspective, this is

the most beneficial to the environment as no new materials are invested into

the production of a new aircraft.

Many of the components in aging aircraft can be recovered before

dismantling, recycling or disposal. These can then be reused on other

aircraft, for example engines, landing gear, electronic motors, in-flight

End-of-life

aircraft

Reuse

Refurbish and reuse for

same purpose

Use aircraft for different

purpose

Reuse specific

components on other aircraft

Reuse of components for different

function

Recycling

Retain quality of material

Obtain a lower quality

material

Recovery

Incineration with energy

recovery

Disposal

Incineration without energy

recovery

Landfill

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entertainment systems, aerofoils, pumps and avionics. The engines are

generally the most valuable components of an aged aircraft; in some cases,

they can even constitute up to 80% of the value recovered from it.

Heat energy can be recovered from incineration of any carbon-containing

materials. The heat energy can be used to generate electricity or for other

functional applications. This is not one of the best options because the

carbon dioxide produced during the burning contributes to the aviation

industry’s carbon footprint, something this project is aimed at reducing.

As a last resort the materials from the aircraft are disposed of either by

incineration without energy recovery or by landfill.

3. CURRENT HANDLING IN EOL PHASE

It is difficult to define a set method by which end-of-life aircraft are

management. This is because different aircraft owners will choose different

routes for their end-of-life aircraft. Several different companies offer services

for the management of end-of-life aircraft and each one does things

differently. The option taken by the owners will often be determined by the

route with minimal losses. In some cases, corporate social responsibility will

push companies to choose the more environmentally friendly option.

According to Asmatulu et al. (2013), Bombardier was the first original

manufacturer to introduce operations in aircraft dismantling. As such, in 2010

Bombardier received dismantling certification from AFRA. The company

disassembled CRJ100/200 jets for refurbishing and some of their parts were

taken for use in other different companies.

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In addition to this, some different companies also provide services at the end

of life stage of an aircraft. These services include decommissioning, disposal,

dismantling and material research. ASI (Air Salvage International),

WINGNET, BARTIN AERO RECYCLING, AELS (Aircraft End-of-Life

solutions) and TARMAC AEROSAVE are some of these companies.

A generalised process in the dismantling and recycling of an end-of-life craft

will normally occur in these stages: decontamination, disassembly and

dismantling, recycling and component management. This process is

described below.

3.1 Decontamination

This is the removal of hazardous materials from the aircraft. ICAO (2015)

outlines a sequence for decontamination which is as follows. Firstly, the

hazardous materials are identified and classified. The next step is

identification of removal methods and all associated risks. The hazardous

materials are then removed and treatment for each one is selected. This

procedure is all in an effort to reduce overall environmental impact, while

ensuring maximum safety for all workers involved. Hazardous materials are

classified as liquid, gas and solid, with the solid ones being the easiest to

handle. The liquids are more difficult to control. In aircraft, jet fuel, turbine oil,

waste water and hydraulic oil are examples of the liquid materials. Solid

materials include batteries, smoke detectors, mercury lamps, and

contaminated filters. Fire extinguishers and oxygen and nitrogen cylinders

are the gases.

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Environmental risks associated with decontamination are soil, water or air

contamination, spills explosions and fires. There are also health risks for

workers, risks of accidents during the process and the risk of incorrect

storage procedures. Cost of the decontamination process is a major

challenge. There are also technological challenges involved with the process.

3.2 Disassembly

This is the parts removal stage. Engines, seats, landing gear, reactors, side

walls, carpets, luggage bins, ceiling panels and all non-metallic components

are removed. It is at this stage that all reusable parts are removed, re-

certified and reintroduced into the market. (Keivanpour, et al., 2015) The

engines are the first to be removed. They are inspected then returned to the

manufacturer in most cases, although depending on the results of the

inspection they may be fitted on other aircraft or stripped down for parts.

3.3 Dismantling, recycling and component management

At this stage the airframe is dismantled, the materials are transported to

recyclers and components are reintroduced into industry. Industrial wrecking

machines shred the fuselage into metals parts which are sent off to the

recyclers. The metal is a mixture of aluminium, zinc and magnesium alloys.

At the recyclers, eddy current machines are used to sort the metal in order to

isolate the aluminium.

It is preferable to pre-sort aerospace alloys before they are shredded, in

order to ensure the highest possible quality of recycled aluminium is

obtained. A practical technique in dismantling is to separate component

groups with the same alloys, such as grouping the wing upper skin, spars

26

and beams together since in the case of the 737 are all made from the same

alloy. Through this type of separation, all non-aluminium components may be

removed before any shredding occurs, thereby reducing the amount of

impurities in the alloys. Availability of records from the manufacturers which

help identify the component materials can be useful in making the

dismantling process easier.

3.3.1 Re-use of recycled aluminium alloys

Recycled aluminium can be used to manufacture components in new aircraft.

However, due to the composition, it would have to be used for components

which are not fracture critical, such as flaps. Components which are designed

on the basis of fracture mechanics concepts should be built from primary

metal.

Typically, an aircraft does not contain a lot of non-critical components; hence

the demand of the metal in this application may not be enough to justify the

re-use of the recycled metal. As such, it is useful to consider applications

outside of the aerospace industry, such as aluminium alloy castings. Another

application is as a deoxidising agent in steel production. It is useful to note

that this application is only possible for aluminium with high iron proportions

of iron in it. (Asmatulu, et al., 2013)

2XXX alloys, when recycled, gives rise to metals high in copper, magnesium,

manganese and silicon while metal from 7XXX alloys will contain high

amounts of zinc, copper and magnesium. If prior to the recycling process the

components were sorted according to 2XXX and 7XXX alloys, then the

27

resultant alloys will have a typical composition as that shown in Figure 11

below.

Constituents

Alloys

Al Cu Fe Mg Mn Si Zn Others

2XXX 93 4.4 0.5 1.0 0.7 0.5 0.1 0.2

7XXX 90 2.0 0.4 2.5 0.2 0.2 6.0 0.2

Figure 11: Composition of the recycled aluminium ( (Das & Kaufman,

2007)

Aluminium manufacture is very energy-intensive because of the Bayer step

(electrolysis). If the aluminium is directly recovered and reused, 90% of the

initial energy is cut down, thereby reducing consumption of raw materials.

The primary production of aluminium consumes about 45 kWh for every

kilogram of the metal produced. On the other hand, production of aluminium

by recycling will only consume about 2.8 kWh per kilogram of metal.

Moreover, only 4% as much carbon dioxide is emitted when recycling, as

opposed to primary production. (Das & Kaufman, 2007)

3.3.2 Cabin interiors

Presently, cabin furnishings are not recyclable, except the aluminium in the

seat frames. As such, they are either sent to landfill or incinerated. Recycling

of plastics and fibres is currently costlier than sending them to landfill.

Considering the fact that cabin furnishings range in weight from 5 tonnes for

a 737 to 10 tonnes for a 747, it is important to consider other end-of-life

options which are friendlier to the environment. (Fitzsimons, 2011) Airlines

will typically schedule cabin upgrades, during which all cabin interiors are

28

replaced, every 10 years. (Towle, 2007) All the waste from this cannot

continue to be landfilled as this is increasingly becoming expensive.

Cabin furnishings consist of several materials and most of them are either

plastics or polymer-based composites. It is difficult to identify and distinguish

between the organic, metallic and the composite materials because all the

materials are used in close combination. Another difficulty is that materials

used in aircraft manufacture have properties that are particular to the

aerospace industry due to rigorous requirements like fire retardation.

Establishing a market for the recovered materials which maximises value

recovery is also a major challenge.

Used seats can be sold to different airliners or individuals for reuse. Air

Support, a French company that sells second-hand seats sold approximately

1,200 passenger seats in 2010. (Fitzsimons, 2011) However, the market has

far less demand than it has supply, so other options need to be explored.

Recycling of the carpets is already proving to be a viable option. As part of its

Take Back program, Desso (a carpet manufacturer) has already started a

carpet recycling project in collaboration with KLM. In 2014, 39 tonnes of

KLM’s carpets were recycled in this program. (AIRFRANCE KLM, 2014)

Another company, Delta and Mohawk Aviation Carpet, launched its ReCover

programme in 2007 under which it collects used carpets from airliners for

recycling. (Fitzsimons, 2011) However, due to lack of regulations in the

aviation industry, airliners are under no pressure to recycle their carpets and

most of them are sent to landfill.

29

Repurposing of the seats is also an option but is very uncommon and is

usually done by aircraft enthusiasts who can turn them into a home or office

chair for example. The aluminium seat frames are removed and recycled

along with the aluminium from the airframe.

4. CASE STUDIES

4.1 The AFRA initiative

The Aircraft Fleet Recycling Association (AFRA) is an international

association and accreditation body which represents the aircraft recycling

industry. Best known for salvaging and recycling components from aging

aircraft, it is dedicated to ensuring end of life airplanes are managed in an

environmentally responsible way. It also focuses on improving the life-cycle

of all aircraft by maintaining and reselling reliable airplanes and returning

them to service. (Mascle, et al., 2013) AFRA was officially launched in 2006

by Boeing. It is a coalition formed to improve end-of-life management of

aircraft. Boeing itself had no intention of recycling the aircraft but only meant

to facilitate for an organisation that would develop a code of conduct for the

management of end-of-life aircraft. The association brought companies from

both Europe and the U.S. into collaboration. These companies specialise in

different fields, including aircraft disassembly, salvaging parts and recycling

of materials. The scope of AFRA’s work encompasses storage of aircrafts

that are not in service, refurbishment of aircraft that could still go back into

service and management of parts from aircraft. It also includes recycling of

the materials that cannot be serviced or directly reused. (Towle, 2007) AFRA

30

is fully industry funded. The founding members of AFRA and their respective

fields of expertise are illustrated in the table in Figure 12 below.

Founding member Field

Adherent Technologies Composite technology, Recycling

Air Salvage International Disposal, Parting out, Dismantling

Bartin Recycling Group Disposal, Parting out, Dismantling

Boeing Aircraft Manufacture

Châteauroux Air Centre Storage, Disposal, Parting out, Dismantling

Europe Aviation Parting Out, Spares, Aircraft Interiors

Evergreen Air Centre Disposal, Parting out, Dismantling

Huron Valley Fritz West Disassembly, Salvaging, Recycling

Milled Carbon, Ltd Material research

Rolls Royce Engine Manufacture

WINGNet/ Oxford University Material Research

Figure 12: AFRA Founding members (AFRA, 2016)

4.1.1 Aims and Objectives

AFRA’s main aim is to develop a code of conduct for retired aircraft

management. (Boeing, 2007) Its goal is to introduce more effective

management of end-of-life activities in aviation. This is manifested in its

provision of an integrated fleet management process to aircraft owners.

(Coppinger, 2006) AFRA aims to improve quality of recycled materials, and

expand markets for these recycled materials both within and out of the

aviation industry. One of the consortium’s goals is to encourage continual

cooperation between its members with regards to technical and managerial

improvements.

4.1.2 Operations

Membership in AFRA is entirely voluntary and open to all companies who are

willing to show that they meet the criteria for membership. The board of

founding members is responsible for approval of membership applications.

31

The consortium offers one or both of two possible accreditations to

companies depending on their expertise, particularly disassembly and

recycling. A guide of best management practice for management of used

aircraft parts and assemblies for recycling of aircraft materials has been

published by AFRA as a guide to all members on how they should operate.

All accredited companies have to be audited to ensure that they comply with

the best management practices (BMP). (AFRA, 2016) The BMP handbook

states all requirements from AFRA; system requirements, facility

specifications, inventory accounting and audits, documentation and records

and parts and removal management.

The author takes a brief look at some of the operations of a few AFRA

members.

Canadian aerospace company Bombardier Aerospace received a

dismantling certification in 2010 from AFRA. In the same year, the company

disassembled 10 CRJ100/200 jets, from which 1500 reusable parts were

salvaged. (Keivanpour, 2015)

Marana Aerospace Solutions, formerly known as the Evergreen Air Centre, is

one of AFRA’s founding members. It is located at a storage field in the

Southern Arizona desert in the U.S. The storage field, which was established

in 1975, accommodates more than 400 aircrafts and dismantles between 24

and 48 of these each year. (de Brito, et al., 2007)

4.1.3 Results

AFRA’s membership rose to over 30 companies from 8 countries within it first

year of operation. (Boeing, 2007) By 2010, it had grown to 41 members, who

32

scrapped an estimated 30% of the world’s end-of-life aircraft. (McConnell,

2010) Since its establishment in 2006, AFRA has contributed to 2000 aircraft

being returned to the market. (AFRA, 2016) These are all aircraft that would

have otherwise been parked indefinitely and probably never returned to

service.

4.2 PAMELA

4.2.1 Introduction

Boeing’s competitor, Airbus launched the PAMELA (Process for Advanced

Management of End-of-Life-Aircraft) Life Project in 2006 with the aim of

recycling aircraft parts in order to protect the environment. It was initiated at

Tarbes Airport in France. SITA (a waste management company), EADS

(European Aeronautic Defence and Space), Sogerma Services and Hautes-

Pyrénés Prefecture were the partners involved in the PAMELA project. Unlike

Boeing, which did not directly involve itself in AFRA’s activities, AIRBUS was

directly involved in the separation and identification of aircraft parts during the

project. The main difference between the AFRA and PAMELA projects was

that Airbus was controlling the process, while Boeing was collaborating with

the partners. (de Brito, et al., 2007)

4.2.2 Aims and Objectives

The PAMELA project’s main objective was to demonstrate that 85-95% of

aircraft components could be recycled, reused or recovered. Furthermore,

the project would pioneer the environmentally friendly end-of-life

management in the aviation industry. It was established to test

33

environmentally friendly methods by which to recycle and dispose of end-of-

life aircrafts. (de Brito, et al., 2007) Another one of the goals was to enhance

eco-efficiency of aircraft and institute new ideals for green management in

the end-of-life phase of aircraft. (McConnell, 2010) Airbus also meant to use

this project to weigh the costs and benefits of recycling the materials and

components of aircraft. The project was also aimed at preventing the trade of

aircraft parts and materials on the black market.

4.2.3 Funding

PAMELA was a €3.3million project and the European Union’s LIFE

(l’Instrument Financier pour l’Environment) programme provided 47% of the

funding for it while the other 53% was industry funded. (Turner, 2006;

Coppinger, 2006)

4.2.4 Operations

The first experiment was on an A300B2-200 which had served 53489 flight

hours from the year 1982. (Coppinger, 2006) The structure of this particular

model consisted of 77% aluminium and 4% composites by weight. (de Brito,

et al., 2007) The PAMELA project did not, however, include aircraft engines.

4.2.5 Results

PAMELA confirmed that as much as 85% of the dry weight of an aircraft can

be recovered for recycling. (Mascle, et al., 2013) Asmatulu et al. (2013) noted

that PAMELA defined three steps which constitute the dismantling process,

namely decommissioning, disassembly and final draining of the systems.

Decommissioning involves cleaning, draining tanks and several safety

34

procedures. Removal of equipment and parts from the aircraft is the

disassembly. In the final draining, hazardous materials are removed and the

aircraft is deconstructed.

The efforts of the PAMELA project resulted in the formation of TARMAC

Aerosave, a joint venture company set up at Tarbes Airport. TARMAC was

established with the aim of further developing the dismantling and recycling

technologies from the project and advancing them to an industrial level.

(McConnell, 2010)

5. SORTING TECHNIQUES

The purity of recycled aluminium is compromised by presence of silicon,

magnesium, zinc and other alloying elements. Thermodynamic obstacles

make it difficult to remove these unwanted elements from the metal.

(Gaustad, et al., 2012) It is imperative to determine ways in which this purity

may be improved, in order to produce aluminium of highest quality. A

common method currently used is dilution with primary-produced aluminium.

This section investigates potential sorting techniques which can be applied.

5.1 Eddy current separation

This method exploits the differences in conductivities of each type of metal in

the mixture. Eddy current separation is already used in aluminium recycling

and does not produce the desired purity level.

5.2 Magnetic sorting

This method is used to separate ferrous component from the non-ferrous

ones. (Gaustad, et al., 2012) Steel and some iron are pulled away from the

35

scrap by magnets. A limitation to the use of this method is that it does not

remove other non-ferrous contaminants like zinc, magnesium and copper.

5.3 Air sorting

In this method. suction is used to pull light-weight materials from the

shredded scrap, such as plastic, rubber and foam. (Gaustad, et al., 2012)

Metals can be separated by feeding material through a column with air

pushing upwards. In this case, the lighter metals move upwards and the

heavy ones collected at the bottom. However, the smaller, lighter pieces of

aluminium may be lost during this process, resulting in wastage.

5.4 Laser induced breakdown spectroscopy

Laser Induced Breakdown Spectroscopy (LIBS) is a laser-based technique

which is a method of atomic emission spectroscopy (AES). The technique

uses a pulsed laser beam and optical emission to analyse a substance.

(Gaustad, et al., 2012) A pulse laser is activated when a sensor detects a

specific material. The material evaporates when radiation energy is locally

coupled into it, hence a plasma is generated which excites the material

constituents and they spontaneously emit radiation. Element-specific

radiation is emitted when the plasma decays. A spectrometer detects and

resolves this emission. (Noll, 2012) Das & Kaufman (2007) suggest that if

LIBS is scaled up enough to handle large aircraft components, it could be

useful in the sorting of aircraft alloys. It is a technique which can be used to

determine elemental composition of materials in real-time. LIBS would have

an advantage over other methods because it has potential for high speed

36

and volume. (Gaustad, et al., 2012) However, for optimal operation, there

must be no paint, coatings or lubricants in the coating.

5.5 Hoopes process

In this three-layer electrolytic process, scrap aluminium is added to an

aluminium copper alloy anode. The cathode is made of purified aluminium.

The Hoopes process requires a lot of energy (17-18kWh/kg) and as such

would not be the most economically beneficial method of separation.

(Gaustad, et al., 2012)

5.6 Low temperature electrolysis

An ionic liquid electrolyte is formed from anhydrous aluminium chlorides. The

anode is the aluminium sample that requires purification. The cathode is

made of pure aluminium or copper. This method can remove manganese,

silicon, copper, iron, zinc, nickel and lead, and is known to produce

aluminium of 99.89% purity. (Gaustad, et al., 2012)

6. RECYCLING CARBON COMPOSITES

Due to technological and economic constraints there are very limited

recycling operations for aerospace composite materials. (Yang, et al., 2012)

The reinforcement on the composites and the matrix or binders make it

particularly difficult to recycle them. At present, there is a very limited

availability of waste composites. In comparison with non-composite polymers

metals, production of composites is relatively small. Moreover, it will take at

the very least 10 years for the composites used in aircraft or automobiles to

37

return for recycling. As such, there is limited availability for waste composites

for economically viable recycling. (Yang, et al., 2012)

There are plenty of existing methods to recover carbon fibre from simple

carbon composites which consist of monolithic fibre-reinforced materials.

However, these methods are not applicable to the advanced composites that

are used in aircraft manufacture. (Gosau, et al., 2006) One of these methods

is pyrolysis, which is thermal decomposition of the polymer at temperatures

between 750 and 950°C. The use of pyrolysis as a recycling technique for

CFRP was attempted in the mid-1990s by research company Adherent

Technologies Inc (ATI). However, the company’s Energy Programs Manager

revealed that they came to a decision that pyrolysis was not the optimal

recycling process for CFRP. (McConnell, 2010) Single step pyrolysis requires

high temperatures, which in turn result in oxidation of the material. Vacuum

pyrolysis, despite preventing oxidation and other adverse chemical reactions,

leaves a layer of ash on the surface of the composite material. This ash (or

char) is undesirable as it hinders good interaction between carbon fibre and

resin matrix, hence producing a weak composite. (Gosau, et al., 2006)

Composites from the automobile industry can be ground into fillers which can

be used in moulding of new composites. This, however, when applied to

high-performance composites such as those used in aerospace, the

expensive fibres are devalued.

Figure 13 below shows the structure of the composite used in the Boeing

787.

38

Figure 13 The layered structure of the 787 composite (Gosau, et al., n.d.)

With the lack of adequate recycling methods, the greater proportion of scrap

composites are sent to landfill, and a few are either incinerated or ground into

fillers. It is not optimal to continue sending all scrap carbon composites to

landfill. Furthermore, there is a chance that bans may be placed on this due

to environmental regulations.

Like most other materials removed from aircraft, the composites are rarely

pure and often contain contaminants such as polyethylene backing, paints,

sealants and metals. As such, the need to pre-sort in order to remove these

contaminants makes finding a solution even harder. Vacuum pyrolysis is

effective in handling contaminants but as mentioned before, results in an

undesirable ash.

ATI has studied the use of high temperature wet-chemical processes as a

recycling method. Upon testing, it was seen that the obtained material

reached 99% purity despite showing 10% less mechanical strength in

comparison with the virgin material. (Gosau, et al., 2006) However, on a

large-scale this method seems very costly. The process conditions are a

temperature of over 300° and a pressure of 500 PSI and since these

39

conditions are atypical in chemical processing, custom equipment is required.

(Gosau, et al., 2006) A low temperature wet-chemical process would be

unable to process some types of impurities.

Boeing has been working with technology firms to discover opportunities in

composite recycling. Tests for this project have been carried out using

composite manufacturing scrap from the 777 and the 787. The tests have

shown that carbon fibres in the CFRP (Carbon Fibre Reinforced Plastic) can

be recovered and recycled.

7. DISCUSSION

There is a high chance that a directive similar to the ELV Directive will be

introduced into the aerospace industry. In anticipation of this, all stakeholders

in the industry should begin to contribute to developments in the end-of-life

management of aircraft. Governments must force aircraft owners to recycle.

(from an environmental perspective) The author has found that the material

composition of aircraft continues to evolve due to demanding requirements in

the industry. The use of composite materials is of particular interest, as the

review of literature reveals that it will only increase. As such, it is imperative

to suggest ways in which recycling of composite materials can be developed.

High costs of virgin carbon fibre mean that a lot of industries would benefit

greatly from use of recycled carbon fibre instead.

7.1 Challenges in dismantling and recycling

The field of dismantling and recycling of end-of-life aircraft already faces

several challenges. Through a review of literature and an analysis of the case

studies, the author was able to determine some of these challenges.

40

The distinctive properties of aerospace aluminium alloys have caused

recycling in aviation to lag behind, in comparison with automotive

applications and packaging, where the recycling of aluminium has become

attractive economically.

Since the only directives which force the aviation industry to become more

environmentally friendly are the REACH (Registration, Evaluation,

Authorisation and Restriction of Chemicals) and RoHS (Restriction of the use

of Hazardous Substances), manufacturers’ designs are mostly influenced by

the market itself. This creates a challenge in that manufacture and material

selection does not necessarily take into consideration the end-of-life

management of the aircraft. Another challenge this creates is that industry

lacks motivation to further develop recycling technology for end-of-life

aircraft. The automotive industry in the EU, for example has been forced by

ELV directive to develop recycling and recovery technology. On the other

hand, in aviation any such developments by organisations are entirely

voluntary. As such, the urgency with which these technologies are developed

is much less in aviation. At present, aircraft owners are under no legal

obligation to recycle their aircraft. Furthermore, as value recovered from

recycling is very minimal, they have no financial incentive to recycle.

In addition to this, the increased use of composite materials in aircraft

manufacture makes the end-of-life problem an even more complex one. As

yet, no economically viable methods of CFRP have been introduced into the

industry. The issues with large scale recycling of composites remains

unresolved.

41

The complexity of cabin interiors is also a problem which means recycling

them is very costly.

7.2 Maximising value recovery

Aircraft owners can recover value from their end-of-life aircraft through

parting out and recycling. The most valuable parts are the engines, avionics,

landing gear and rotable parts. The high-quality alloys that make up the

airframe could also be valuable. Cost of recycling aircraft is often more than

the value recovered, hence aircraft owners have no incentive to recycle their

aircraft. The absence of any government regulations does nothing to better

the situation. From an environmental perspective, governments should

introduce regulations that will force aircraft owners to recycle.

Recovery of aluminium is especially beneficial since use of secondary

aluminium is more conservative than use of primary aluminium manufactured

using bauxite. The quality of the recycled aluminium, however, is not

compliant with material requirements in aircraft manufacture, hence it has to

be used for other applications. However, to increase quality of recycled

aluminium, and consequently value recovered, improved separation

techniques should be employed.

7.3 Recommendations

It is imperative to consider personal and environmental protection when

developing technologies for end-of-life management for aircraft.

Contamination of the environment must be avoided as this not only

counteracts the green efforts of recycling, but could incur charges from

environmental protection agencies.

42

Separation methods must be improved in aluminium recycling. The author

suggests Laser Induced Breakdown Spectroscopy and low temperature

electrolysis as the best methods. This is because they provide the highest

possible purity, and the products may be reused in aircraft manufacture.

Investment in composite recycling technology must be increased.

Governments should introduce legislations that accelerate innovation in this

field such as a ban on landfilling, or a landfill quota.

Manufacturers should consider recyclability in their designs. Designs should

have least possible complexity, without compromising safety of course. This

will help reduce the complexity of the end-of-life problem It is recommended

that material identification tags be introduced by manufacturers. This could

be in the form of barcodes. Obviously, tagging of critical components might

be considered risky.

7.4 Conclusion

In anticipation of an end of life directive, all stakeholders in aviation should

focus on improving the dismantling and recycling of aircraft. The purpose of

this project was to suggest ways in which this could be done. Through an

extensive literature review and the case studies of AFRA and PAMELA, the

author was able to identify problems within the field of dismantling and

recycling of commercial aircraft. These are the impurity of recycled

aluminium, the difficulty in composite recycling and cabin interior treatment.

The project has suggested ways in which the field can be improved.

43

7.5 Future Work

There is a considerable amount of work and research that can still be done

following this project. This includes further research on tagging methods

which will aid in component identification at the end of life. Further research

can be done to determine more efficient ways to recycle CFRP.

44

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Appendix

Below are the Gantt charts used by the author for the management of the

project.

Final Dissertation

Documents

Transcript of Final Dissertation