Master’s thesis project

Innovative research into fire certification of aircrafts’ cabin

refurbishment

TRITA AVE 2011:18 - ISSN 1651-7660

Frederic Le MoullecDepartment of Aeronautical and Vehicle Engineering,Royal Institute of Technology of Stockholm - KTH,

SE-100 44, Stockholm, Swedenflm@kth.se

February, 28th 2011

Abstract

VIP aircrafts cabin interiors are refurbished according to specific needs of very demandingcustomers. In the mean time, international airworthiness authorities set high standard andinevitable certification procedures which do not provide the necessary freedom to fulfill suchrequests. This study points out four innovative ideas likely to lead to the drafting of approvednew methods of compliance.

Contents

1 Introduction 3

2 Design tools and guidelines 3

2.1 CS25.853 . . . . . . . . . . . . . 3

2.2 CS25 Appendix F - Part I . . . . 4

2.3 Structural constraints . . . . . . 5

3 Approach 5

4 Innovative solutions 5

4.1 Similarity . . . . . . . . . . . . . 5

4.2 Commonality . . . . . . . . . . . 6

4.3 Core drilling . . . . . . . . . . . . 7

4.4 Fire-blocking layer . . . . . . . . 7

5 Results and analysis 8

5.1 Core drilling test campaign offeasibility . . . . . . . . . . . . . 8

5.2 Fire-blocking layer test cam-paign of feasibility . . . . . . . . 9

6 Conclusions 10

7 Acknowledgments 11

Appendices 12

Appendix 1 EASA CertificationSpecifications for Large Aero-planes CS-25/Amdt 10 - Section25.853 Compartment interiors . . 12

Appendix 2 CS25 - Appendix F -Part I - Test Criteria and Pro-cedures for Showing Compliancewith CS25.853, 25.853 or 25.869 . 13

Appendix 3 Most relevant meth-ods of compliance for FAR/CS§25.853 proposed in FAA draftpolicy memo ANM-115-09-XXX . 16

Appendix 4 Photographs of thesamples manufacturing processrelative to the FBL preliminarycampaign . . . . . . . . . . . . . 16

Appendix 5 Results of the FBL pre-liminary test campaign . . . . . . 18

Appendix 6 Photographs of theburnt samples relative to theFBL preliminary campaign . . . 19

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1 Introduction

Air transport is fortunately subject to veryhigh standards of safety promoted by the inter-national authorities - EASA1 and FAA2 - butthat amount of rules sometimes slows down se-condary industrial activities like large aircrafts’cabin interiors refurbishment.This venture consists in changing the finishesor decorative surfaces of compartment interiorsby keeping the existing panels. There existsdifferent types of cabin panels: floor panels,wall panels, window panels, class-dividers, fur-nitures, doors, overhead compartments... butthey all are composite honeycomb ones. Re-furbishment is more economical in comparisonto complete cabin renewal -i.e. removing allexisting parts and installing new ones- but itcreates many certification issues.Since cabin fire is a main cause of fatality inaircraft accidents, the authorities are continu-ously implementing and monitoring fire safetyrules which are to be strictly applied. Theirresponsibility include the type-certification ofaircraft and components, which means everysingle new part as well as any major modifica-tion on one already in place must be approved.That concretely implies that every materials’assembly - panel / glue / decorative layer(s) -introduced in an aircraft has to be fire testedaccording to EASA procedures. In the case ofa refurbishment, thus there are two options sofar:

• the references of all layers are availableand the fire certificate of this exact as-sembly can be produced by testing eithera spare panel or a newly manufacturedpanel;

• the existing panel must be sampled to firetest the new assembly.

The first option is only possible if the panel canbe identified throughout the available docu-mentation and yet the technical documentationis fairly not entirely provided by the originalmanufacturer or previous refurbisher. On the

other hand, it can be impossible to sample thepanel regarding its size, shape, uniqueness orstructural issues. In the end, the actual legis-lation makes the refurbishment’s certificationvery hard and there is a need for innovativesolutions which could lead to the drafting ofnew legislation. This is an even more impor-tant requisite for VIP aircrafts since the cus-tomers’ requirements are concerning rare ma-terials whose references certification is exclu-sively kept by the previous refurbisher.In the VIP market, cabin interiors fitting com-panies are thus more likely to avoid these certi-fication issues and offer their customer the re-completion method. Air France Industries3 Re-search & Development department decided toconduct a study to find a way to solve thoseissues. Our project comes within the scope ofthis research work, in parallel to the FAA Mate-rials Fire Test Working group activities. Whilethis think tank is more focusing on how to im-prove the materials fire resistance, we aim toset up innovative processes, demonstrate theirreliability through test campaigns and submitthem to the authorities for further application.

2 Design tools and guidelines

Our study must comply with the aeronauticallegislation from which the relevant parts for usare CS25.853 and its appendix F. In addition tothat, there are structural constraints by parts’manufacturers.

2.1 CS25.853

The main guidelines are provided by theFAA through Federal Acquisition Regulations(FAR). Our project falls within the scope ofpart 25 - Airworthiness standards for trans-port category airplanes, subpart D - Designand Construction, section 25.853 - Fire Protec-tion of Compartment interiors. The Certifica-tion Specification CS25.853 is the exact equiva-lent in the EASA legislation and is available asAppendix of this report. Those transcripts in-clude a so-called Appendix F 4 which prescribes

1European Aviation Safety Agency2American Federal Aviation Administration3Further designated as AFI.4Also available as Appendix of this report.

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the applicable test criteria. CS/FAR25.853 setsthe following.

(a) Materials (including finishesor decorative surfaces applied to thematerials) must meet the applicabletest criteria prescribed in Part I ofAppendix F.

Paragraph (c) refers to part II of appendixF which lists additional requirements for seatcushions which are out of our scope. The nextrelevant paragraph5 (d) draws up the appli-cability of Heat Release and Smoke Emissiontests requirements (Parts IV and V of appendixF). In the frame of VIP refurbishment, therare materials being used, especially the natu-ral ones, do not pass these tests: wood, leatherand other special synthetic materials release

lots of smoke and heat. Parts IV and V haveas objective to guarantee a complete evacua-tion of the plane within 90 seconds in case ofa kerosene fire outside the aircraft penetratesthe cabin. A partial exemption of these re-quirements is granted6 by the authorities in thescope of VIP refurbishments if it is proven theevacuation can be completed within 30 (FAA)or 45 seconds (EASA). This requirement is easyto meet considering the low number of pas-sengers in a private large aircraft compared tocommercial air carrier’s plane. Plus, VIP pas-sengers are likely to be familiar with the cabininteriors which provide them the ability to es-cape it faster. In this way, this study will notintend to reach parts IV and V requirementsand focus on part I certification issues.

Test ApplicabilityRequirements (maximum values)

Flametime(s)

Burnlength(mm)

Drippingsflametime (s)

Burnrate(mm/min)

12s verticalFloor covering, textiles, seatcushions, decorative and non-decorative coated fabrics...

15 200 5 -

60s vertical

Interior floor, ceiling andwalls panels, partitions, galleystructure, large cabinet walls,stowage compartments...

15 150 3 -

30s with 60o

bank angleElectrical system components 30 76 3 -

15s horizontal

Clear plastic windows andsigns, seat belts, shoulderharnesses, baggage tiedownequipments, bins...

- - - 64

15s horizontal Other parts - - - 102

Table 1: Summary of Test Criteria and Procedures for Showing Compliance with CS25.853

2.2 CS25 Appendix F - Part I

Part I aims to test the materials self-extinguishibility by bunsen burning a minimumof three samples and measuring the averageburn length, the average flame time after re-moval of the flame source and average flametime of drippings after falling down or the

average burn rate. The test conditions andrequirements are dependant on the type of ma-terial. Table 1 above briefly describes the dif-ferent applicable tests, see Appendix 2 for moredetails. All these tests other than the 60s ver-tical one refer to single parts whose applicablefire test certificates are usually provided by

5Paragraphs b and e to h are irrelevant in our scope of study.6Confidential Certification Review Item between Air France and the EASA.

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the manufacturer when installed and standingalone in the cabin. As a panel refurbisher, wedo not need to test the new decorative layer it-self, but the construction i.e. old panel + glue+ new decorative layer, which corresponds tothe 60s vertical test described below.

Thus, the certification methods to be definedin this study are innovative ways to get the60s vertical test certificate of the refurbishedpanel.

2.3 Structural constraints

All rules regarding the complete or part mod-ification of an assembly are provided by themanufacturer through so-called Structural Re-pair Manual (SRM) or Component Mainte-nance Manual (CMM). These documents ex-plain in details how parts shall be repaired de-pending on the damage so the structural pro-perties of the assembly are not spoiled and itscertification remains valid. The solutions to beset through this study will thus have to comewithin the scope of these manuals.

3 Approach

The first inevitable step has been to closelyread and analyze the legislation set by the

EASA and the FAA as well as the inputs pro-vided by the FAA Materials FireTest Work-ing group. These references are to set the mainguidelines and design tools which are describedin section 2. From this, a brainstorming origi-nally revealed the following four ideas.

• similarity;

• commonality;

• core drilling;

• fire-blocking layer.

They must be considered as symbiotic inputs:while core drilling is a solution to identifyan unknown panel, the concepts of similarityand commonality aim to minimize the num-ber of certificates to be produced accordingto the documentation available. On anotherhand, fire-blocking layer acts as a refurbish-ment method that avoids fire testing. Depend-ing on the information available about the ex-isting panel, we are likely to use one or moreof these four to get the refurbished panel cer-tified. The next section will present in detailthose concepts.

4 Innovative solutions

4.1 Similarity

The principle of similarity is to substantiate thecertification of a panel with data from anotherone which has similar characteristics.FAA Policy Memorandum ANM-115-09-XXX,published7 so far as a draft version by theFAA Materials Fire Test Working group, is animportant document to be considered for ourstudy since it

provides guidance on accept-able methods of compliance withthe flammability requirementsof FAR/CS Part 25 25.853(a)and (d).

It actually establishes the criteria of similaritywhich are either

[Part 1] acceptable

or those which are

7http://fire.tc.faa.gov/pdf/FlammabilityTestingofInteriorMaterials.pdf

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[Part 2] expected to be accept-able but require test data to supportthem.

Appendix 3 lists the most relevant criteria forus. In the frame of this project, we managed8

to get the EASA approval for considering allcriteria as acceptable methods of complianceand the similarity principle applicable on fur-ther projects. Nevertheless, the prerequisite isto obtain the certification of the reference paneland to fulfill the criteria of similarity.Let’s consider an aircraft’s refurbishmentwhere the same laminate in two different colorshas to be laid. If the original design data pointsout that the panels to be refurbished in colorA and those in color B are exactly the same,there will be no need to sample both panelsin order to substantiate the fire certification ofboth. Decreasing the number of fire certificatesto be produced is the first interest of similarity.Furthermore, we can avoid sampling panels inthe frame of each new project by referring to afire certificate obtained in the frame of a previ-ous project. In this purpose, a database shallbe set up to gather all fire tests with a de-tailed description of the layers so we increasethe chances of finding a corresponding refer-ence panel for each refurbished one. For ex-ample, the fire certificate of a composite panelX with the glue Y and the synthetic leatherZ in blue would be the reference for the refur-bishment of a panel provided that the docu-mentation clearly identifies the existing panelas being panel X and that we use the glue Yand a synthetic leather Z in any of its colors.This database is especially relevant for the so-called standard parts which are ceiling, dado9,windows and closure10 panels, overhead com-partments and toilets blocks. In VIP aircraftinteriors, those elements are situated in the sec-tions in commercial airline layout intended foraccompanying people (bodyguards, journalists,private staff...). Standard parts are likely tobe refurbished with the same finish of anothercolor and the panel often comes from com-mon manufacturers such as Airbus, Boeing,Sell and Dasel whose products are well known.

Thus, the similarity principle is an interestingmethod of the fire certification mainly for stan-dard parts and more individually of VIP fur-nishing elements provided that the panel cha-racteristics are given and a reference panel isidentified.

4.2 Commonality

As for similarity, the alternative substantia-tion method commonality aims to decrease thenumber of samplings and fire tests by identi-fying groups of panels that have identical de-sign. The difference is in the definition of the”identical”. While similarity requires the ex-act knowledge of the different layers so to provethe criteria of similarity is the only difference,commonality only requires the assurance thatpanels are the same regarding fire behavior, notmatter whether they actually are. For instance,this principle allows us to consider that a two-windows and a one-window window panel arethe ”same” even if they do not have the samepart number. Thus, the idea is to sample andfire test one panel to substantiate the certifi-cation of all panels of this commonality group.The point is to agree with the authority aboutthe definition of a group. AFI managed toset the criteria but they must unfortunately bekept confidential for patent rights issues.For example, let’s consider a piece of furniturewith 10 doors. If the documentation points outthat the 10 doors are the same but does notgive the characteristics of the panel, similarityis not applicable but commonality applies: in-stead of sampling and burn the 10 doors, wewill sample one of the door, remove the oldfinish, lay the new one and burn the assem-bly. If it passes the §25.853 requirements, thenall 9 remaining doors are certified in their newlayout. The sampled panel is also fire certi-fied but given the size of the samples (threetimes 76x305mm i.e. ca.7dm2 - see Appendix2) it is no longer valid, because of structuralconstraints and must be either repaired or re-placed as explained in section 2.3. Most of thetime, CMMs and SRMs do not cover such sam-plings and a replacement is inevitable. Thus,

8For patent rights issues, the arguments cannot be detailed in this report.9Vertical panel between the floor and the window panel.

10Curved panel between the window panel and the ceiling.

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there are two possibilities: either the panel is astandard part which can be purchased as spareparts based on its reference or we need to re-design it against the following procedure:

• If the panel is part of a structural as-sembly, we replace it with an availabledifferent panel complying with §25.853requirements and we check the struc-tural resistance of the furniture by finite-elements methods.

• If the panel is not part of a structuralassembly, we measure its size, thicknessand weight and manufacture an equiva-lent panel having these three characteris-tics and complying with §25.853 require-ments.

We see here that this retro-engineering is anapplicable limit of commonality. Nevertheless,as it is a complementary to similarity, we cansignificantly group all panels to be refurbishedand in this way decrease the number of sam-plings and tests needed or even avoid them ifwe can find a corresponding panel in such a”fire tests database”.

4.3 Core drilling

The idea of core drilling is to identify an un-known composite panel by analyzing a sampleof it, ideally a 1-inch squared piece so SRMsand CMMs can cover the reparation procedure.This process is a solution to an eventual lack ofdesign data leading to the impossibility of ap-plying similarity and/or commonality. Thus,core drilling is eventually a preliminary proce-dure to one or both these principles. Discus-sions with labs lead to the list of parametersneeded to determine reliably the different layersof a composite panel. For the plies, these pa-rameters are required: resin type, fabric type,number of layers of fabric, fabric weight, fabricweave and style, resin content; as for the honey-comb core: material type, cell shape, cell sizeand density. To validate this method, we aimedto complete the following steps:

• Test campaign to ensure the feasibility;

• Results analysis;

• AFI Compliance Verification Engineers’(CVE) validation;

• Test campaign to demonstrate the relia-bility;

• Results analysis;

• CVEs validation;

• Authority’s validation.

AFI agreed with a laboratory on the followingprocedure for the composite panel determina-tion.

1. Sample preparation: cutting, washing,core/skins separation, removal of the toppainted layer;

2. Resin identification through infrared spec-troscopy;

3. skinand core resin chemical analysis throughpyrolysis, gas chromatography and massspectrometry;

4. Fabric identification (thermal degradation ifglass fabric, chemical treatment if carbonfabric);

5. Resin content determination through com-parative weighing;

6. Fabric weight weighing;

7. Fabric fiber weave and style and core cellsize and shape determination through scan-ning electron microscope (SEM) analysis;

8. Core density measurement.

In the scope of this project, the first test cam-paign has been performed: the results andanalysis are presented in section 5.1. Thanks tothe product sheets of the tested panels, we cancompare the theoretical values with the mea-sured one and check if the panel’s reference iscorrect. Thus, we can conclude on the relia-bility of the lab’s measurements and its abilityto identify the panel correctly.

4.4 Fire-blocking layer

This method consists in laying down a flameretardant layer between the panel and the de-corative layer, as shown on the following figure:

We intend to demonstrate that this materialhas a significant positive impact on the fireresistance of the decorated panel. As a first

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step, samples of the most used materials willbe tested according to the 60s vertical Bunsenburner test (F1) with and without the flameretardant layer in order to get an idea of thequalitative and quantitative fire resisting effectusing this material in assemblies. If the resultsare convincing, the reliability of this methodis to be enhanced with a larger market rep-resentative sampling. We aim to prove thatthe addition of the flame retardant layer willensure that the refurbishment with a new trimand finish fulfills all CS25.853 requirements,considering what the previous one was. At theend, we plan on adopting the same approachas for core drilling:

• Test campaign to ensure the feasibility;

• Results analysis;

• AFI CVEs’ validation;

• Test campaign to demonstrate the relia-bility;

• Results analysis;

• CVEs validation;

• Authority’s validation.

Fire test plan Only two types of panels areused on aircrafts which are likely to be refur-bished: wooden and honeycomb panels. Thus,we will be provided a 5mm thick panel of eachtype, which is the thinnest available accordingto our experience and the principle of similar-ity applies for panel thickness (see Appendix 3)- Reference number 2). The first sampling fo-cuses on four common trims and finishes: syn-thetic leather, fabric, laminate and paint. Foreach type, we will be provided one representa-tive reference. As for the adhesive, a standardAFI aeronautical glue will be used.The flame retardant material chosen in thisflammability test is called a mica paper. Micais a mineral which can withstand temperaturein excess of 1000oC, it is flame-retardant, non-flammable, does not give off fumes and con-ducts very little heat. Mica paper consists ina continuous layer of mica flakes squeezed be-tween fiberglass and silicon. This paper is cur-rently in use in the aeronautical industry forthe fuselage insulation thanks to its high burn-through resistance.

All combinations of 2 panels and 4 trims & fin-ishes will be manufactured and tested with andwithout the fire retardant layer, which makes16 different samples, each of them being man-ufactured in four pieces according to the min-imum of three required in §25.853, AppendixF, part I, paragraph (4) (see Appendix 2) andsince our fire testing laboratory asks for oneextra piece.

The samples manufacturing process isas follows, see Appendix 4 for photographs:

1. Cutting of all materials in 320x320cmpieces;

2. Application of glue on the wooden and com-posite panels;

3. For the samples with mica paper:

(a) Laying of the mica;

(b) Application of glue;

4. Laying of the decorative layer or painting.

The samples have been sent to a FAA certi-fied laboratory which will proceed to the 60svertical bunsen burner tests according to thetest procedure described in §25.853, AppendixF, part I, paragraph (b) (see Appendix 2). Theresults and the analysis are presented in section5.2.

5 Results and analysis

This section will detail the results of both testcampaigns core drilling and fire-blocking layer.The analysis shall conclude the feasibility ofthese methods.

5.1 Core drilling test campaign offeasibility

In order to ensure the feasibility of core drillingfor the identification of a composite panel, wehave been provided samples of three differ-ent panels referring to three different interna-tional specifications: Jamco (Japan), Airbus(Europe) and Boeing (USA). Those three sam-ples have been sent to the lab for determinationof all characteristics according to the proceduredescribed in subsection 4.3 as well as identifica-tion of the panel’s reference. The exact numer-ical results cannot be presented in this report

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because of patent rights issues on the materi-als specifications. Nevertheless, table 2 sum-marizes the differences between the measuredvalued and the theoretical parameters for theskin’s analysis11.This comparison highlights the following pointsof analysis.

– The determination of the parameters weightand resin content is very reliable for one-skincomposite panels.

– For the multiple skins panel - sample 1, thesevalues are inaccurate because of the difficultdifferentiation between the two plies. Theresin type is even false for sample 1 becauseof residual glue traces.

– The fabric’s weave and style are determinedaccurately.

– Sample 1 comes from the japanese manufac-turer. Since the laboratory does not have itspanels’ specifications, it has not been able tolink it.

ParametersSample 1 Sample 2 Sample 3

Skin 1 Skin 2 Skin 1 Skin 1

Resin type wrong wrong right right

Fiber type right right right right

Fabric weight(relative devia-tion)

8% (4% max.) 4% (10% max.) 0.6% (5% max.) 2% (4% max.)

Fabric weave &style

right right right right

Resin content(relative devia-tion)

28% (6% max.) 18% (6% max.) 4% (6% max.) 10% (5% max.)

Panel reference not determined not determined correct correct

Table 2: Comparison of the core drilling test campaign’s results with materials specifications.

AFI is still expecting some inputs concern-ing the minimum sample’s size required to per-form all these tests and the core analysis re-sults. Already, the procedure is to be upgradedin order to avoid the uncertainties and to makethis method more reliable.

5.2 Fire-blocking layer test cam-paign of feasibility

As we saw earlier, the 60s vertical test includesthe measure of the burn length, the extinguish-ing time after flame removal and the extin-guishing time of the drippings. Since no drip-pings were observed for all burnt samples, thereis no value for the extinguishing time of the

drippings. On the other hand, figures 1 and 2in Appendix 4 present the average values forthe two other parameters.One can see that the wooden assemblies donot pass the test since the extinguishing timereaches 24 to 73 seconds whereas §25.853 limitis 15 seconds (see again table 1). On the con-trary, the burn length complies with the re-quirements. As for the composite based sam-ples, they easily pass the 60s vertical test asboth parameters do not even reach half thelimit. One of the reason is that ply-wood con-tains a lot of glue which served to fix the dif-ferent wooden plies. In the future, we have tobe very careful with such old panels to be re-furbished.

11Results of the core’s analysis not yet available.

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Sample DescriptionInfluence of mica paper

Extinguishing time (%) Burn length (%)

B1 Wood-Paint -34 -28

B2 Wood-Synthetic leather +20 -1

B3 Wood-Fabric +14 +18

B4 Wood-Laminate -43 -15

C1 Composite-Paint -16 -12

C2 Composite-Synthetic leather 0 +11

C3 Composite-Fabric +35 -9

C4 Composite-Laminate -19 -3

Table 3: Relative standard deviation of measured burn length and extinguishing time

Let’s now look at the influence of the micapaper thanks to the following table 3 whichdisplays the relative standard deviation be-tween the values with and without the flameretardant. It is obvious that this effect is com-pletely hazardous when looking at the valuesonly: they do not point out any tendency toextinguish better the flame and neither to re-duce the burn length.The photographs of the burnt samples areavailable in Appendix 6. They are a visualconfirmation of the average values, which arecalculated from the measured values of each ofthe three samples of each type. Nevertheless,we can observe by looking closer at the follow-ing figure that the mica paper partly remains:while the silicon burnt away, the fiber and themica flakes are carbonized but not consumed.This confirms the very good fire resistance ofmica and eventually its ability to retard theflame propagation for a burn-through test butit did not help it for our vertical burn tests.The idea of the mica being such a good fireinsulator that it could isolate the panel andthe decorative layer to limit burning is invalid.

As a conclusion of this method, we can say thatmica in a paper application is not dependablesolution as fire-blocking layer. Further studieshave to be performed to find another way of re-vealing mica’s excellent fire properties in thatpurpose.

6 Conclusions

This project highlighted four innovative solu-tions for the fire certification of VIP cabininteriors refurbishments. On one hand, simi-larity and communality are principles that arenow approved by authorities. Their relevance ison a case to case basis as it is dependant on theconsistency of the documentation. The moreinformation available on the existing panels,the more we can gather them into groups andtherefore the less certification data is required.On the other hand, when regarding unknownpanels, core drilling is a solution that can be-come more and more reliable and there are pos-sibilities of finding a material that can have theexpected flame-resistant properties. Thus, thisstudy has to be carried out to solve those issues.Before applying a method, it is worth consid-ering the economic issues. For example, themore parts there are in a commonality group,the more interesting this method becomes, pro-vided we have all necessary design data. Insome cases, such as the refurbishment of aunique piece of furniture, it is also crucial tocompare the price of replacing it with a new oneto how much the core drilling analysis of thedifferent parts will cost. At the end, it is im-possible to draw up a standard decision matrix

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since certification issues are so different fromone refurbishment project to another. Never-theless, this six-months study pointed out someinteresting tools for the fire certification of VIPcabin interiors refurbishment and is a goodstart for further developments.

7 Acknowledgments

I would like to express my gratitude to myindustrial supervisor, Jean-Paul Gresset, de-sign manager at Air France Industries, for hiscomplete confidence and guidance as well ashis patience all along this project. I wish toacknowledge design engineers Sylvain Lecointeand Johan Grenier for their expertise and pre-cious help and Jean-Jacques Michel, ExecutiveVice-President Engineering Aircraft Modifica-

tions, for the genuine interest he took in myproject. I would also like to thank FabriceLeszczyk and Antoine Deledalle for their sin-cere moral support and friendship during thesesix months as well as all my other colleagueswhose kindness and knowledge made this ex-perience within Air France very pleasant andenriching.I must also acknowledge my academic su-pervisor, PhD Per Wennhage (KTH), for hisguidance and availability and Pr. Simon Davies(Ecole Centrale) for his motivation and supportduring my double-degree program.I would also like to thank my family, friendsand girlfriend without whose fidelity and pa-tience I would not have successfully completedthose seven exciting years of studies fromToulouse to Stockholm via Lille, Hamburg,Paris and Kourou.

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Appendices

Appendix 1: EASA Certification Specifications for Large AeroplanesCS-25/Amdt 10 - Section 25.853 Compartment interiors

For each compartment occupied by the crewor passengers, the following apply:

(a) Materials (including finishes or decora-tive surfaces applied to the materials) mustmeet the applicable test criteria prescribed inPart I of Appendix F or other approved equiv-alent methods, regardless of the passenger ca-pacity of the aeroplane.

(b) Reserved

(c) In addition to meeting the requirementsof sub-paragraph (a) of this paragraph, seatcushions, except those on flight crewmemberseats, must meet the test requirements of partII of appendix F, or other equivalent methods,regardless of the passenger capacity of the aero-plane.

(d) Except as provided in sub-paragraph (e)of this paragraph, the following interior com-ponents of aeroplanes with passenger capaci-ties of 20 or more must also meet the test re-quirements of parts IV and V of appendix F, orother approved equivalent method, in additionto the flammability requirements prescribed insub-paragraph (a) of this paragraph:

(1) Interior and wall panels, other thanlighting lenses and windows;

(2) Partitions, other than transparentpanels needed to enhance cabin safety;

(3) Galley structure, including exposedsurfaces of stowed carts and standard contain-ers and the cavity walls that are exposed whena full complement of such carts or containers isnot carried; and

(4) Large cabinets and cabin stowagecompartments, other than underseat stowagecompartments for stowing small items such asmagazines and maps.

(e) The interiors of compartments, such aspilot compartments, galleys, lavatories, crewrest quarters, cabinets and stowage compart-ments, need not meet the standards of sub-paragraph (d) of this paragraph, providedthe interiors of such compartments are iso-lated from the main passenger cabin by doorsor equivalent means that would normally beclosed during an emergency landing condition.

(f) Smoking is not to be allowed in lavatories.If smoking is to be allowed in any other com-partment occupied by the crew or passengers,an adequate number of selfcontained, remov-able ashtrays must be provided for all seatedoccupants.

(g) Regardless of whether smoking is allowedin any other part of the aeroplane, lavatoriesmust have self-contained removable ashtrays lo-cated conspicuously both inside and outsideeach lavatory. One ashtray located outside alavatory door may serve more than one lavatorydoor if the ashtray can be seen readily from thecabin side of each lavatory door served.

(h) Each receptacle used for the disposal offlammable waste material must be fully en-closed, constructed of at least fire resistant ma-terials, and must contain fires likely to occur init under normal use. The ability of the recep-tacle to contain those fires under all probableconditions of wear, misalignment, and ventila-tion expected in service must be demonstratedby test.

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Appendix 2: CS25 - Appendix F - Part I - Test Criteria and Procedures forShowing Compliance with CS25.853, 25.853 or 25.869

(a) Material test criteria

(1) Interior compartments occupied by crewor passengers.

(i) Interior ceiling panels, interior wallpanels, partitions, galley structure, large cab-inet walls, structural flooring, and materialsused in the construction of stowage compart-ments (other than underseat stowage compart-ments and compartments for stowing smallitems such as magazines and maps) must beself-extinguishing when tested vertically in ac-cordance with the applicable portions of PartI of this Appendix. The average burn lengthmay not exceed 15 cm (6 inches) and the aver-age flame time after removal of the flame sourcemay not exceed 15 seconds. Drippings from thetest specimen may not continue to flame formore than an average of 3 seconds after falling.

(ii) Floor covering, textiles (includingdraperies and upholstery), seat cushions,padding, decorative and nondecorative coatedfabrics, leather, trays and galley furnish-ings, electrical conduit, air ducting, jointand edge covering, liners of Class B and Ecargo or baggage compartments, floor panelsof Class B, C, E or F cargo or baggage com-partments, cargo covers and transparencies,moulded and thermoformed parts, air ductingjoints, and trim strips (decorative and chaf-ing), that are constructed of materials not cov-ered in sub-paragraph (iv) below, must be self-extinguishing when tested vertically in accor-dance with the applicable portions of Part Iof this Appendix or other approved equivalentmeans. The average burn length may not ex-ceed 20 cm (8 inches), and the average flametime after removal of the flame source may notexceed 15 seconds. Drippings from the testspecimen may not continue to flame for morethan an average of 5 seconds after falling.

(iii) [...] (irrelevant)

(iv) Clear plastic windows and signs,parts constructed in whole or in part of elas-tomeric materials, edge lighted instrument as-semblies consisting of two or more instrumentsin a common housing, seat belts, shoulder har-nesses, and cargo and baggage tiedown equip-ment, including containers, bins, pallets, etc,used in passenger or crew compartments, maynot have an average burn rate greater than 64mm (2 · 5 inches) per minute when tested hori-zontally in accordance with the applicable por-tions of this Appendix.

(v) Except for small parts (such as knobs,handles, rollers, fasteners, clips, grommets, rubstrips, pulleys, and small electrical parts) thatwould not contribute significantly to the prop-agation of a fire and for electrical wire andcable insulation, materials in items not spec-ified in paragraphs (a)(1)(i), (ii), (iii), or (iv)of Part I of this Appendix may not have a burnrate greater than 102 mm/min (40 inches perminute) when tested horizontally in accordancewith the applicable portions of this Appendix.

(2) [...] (irrelevant)

(3) Electrical system components. Insulationon electrical wire or cable installed in any areaof the fuselage must be selfextinguishing whensubjected to the 60 degree test specified in PartI of this Appendix. The average burn lengthmay not exceed 76 mm (3 inches), and the aver-age flame time after removal of the flame sourcemay not exceed 30 seconds. Drippings from thetest specimen may not continue to flame formore than an average of 3 seconds after falling.

(b) Test Procedures

(1) Conditioning. Specimens must be con-ditioned to 21 · 11 ± 3◦C (70 ± 5◦F ) and at50%±5% relative humidity until moisture equi-librium is reached or for 24 hours. Each speci-men must remain in the conditioning environ-ment until it is subjected to the flame.

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(2) Specimen configuration. Except forsmall parts and electrical wire and cable in-sulation, materials must be tested either as asection cut from a fabricated part as installedin the aeroplane or as a specimen simulatinga cut section, such as a specimen cut from aflat sheet of the material or a model of the fab-ricated part. The specimen may be cut fromany location in a fabricated part; however, fab-ricated units, such as sandwich panels, may notbe separated for test. Except as noted below,the specimen thickness must be no thicker thanthe minimum thickness to be qualified for usein the aeroplane. Test specimens of thick foamparts, such as seat cushions, must be 13 mm(1/2-inch) in thickness. Test specimens of ma-terials that must meet the requirements of sub-paragraph (a)(1)(v) of Part I of this Appendixmust be no more than 3 · 2 mm (1/8-inch) inthickness. Electrical wire and cable specimensmust be the same size as used in the aeroplane.In the case of fabrics, both the warp and filldirection of the weave must be tested to deter-mine the most critical flammability condition.Specimens must be mounted in a metal frameso that the two long edges and the upper edgeare held securely during the vertical test pre-scribed in sub-paragraph (4) of this paragraphand the two long edges and the edge away fromthe flame are held securely during the horizon-tal test prescribed in sub-paragraph (5) of thisparagraph. The exposed area of the specimenmust be at least 50 mm (2 inches) wide and 31cm (12 inches) long, unless the actual size usedin the aeroplane is smaller. The edge to whichthe burner flame is applied must not consist ofthe finished or protected edge of the specimenbut must be representative of the actual cross-section of the material or part as installed inthe aeroplane. The specimen must be mountedin a metal frame so that all four edges are heldsecurely and the exposed area of the specimenis at least 20 cm by 20 cm (8 inches by 8 inches)during the 45◦ test prescribed in sub-paragraph(6) of this paragraph.

(3) Apparatus. Except as provided in sub-paragraph (7) of this paragraph, tests must beconducted in a draught-free cabinet in accor-dance with Federal Test Method Standard 191

Model 5903 (revised Method 5902) for the ver-tical test, or Method 5906 for horizontal test(available from the General Services Admin-istration, Business Service Centre, Region 3,Seventh & D Streets SW., Washington, DC20407). Specimens, which are too large for thecabinet, must be tested in similar draught-freeconditions.

(4) Vertical test. A minimum of three spec-imens must be tested and results averaged. Forfabrics, the direction of weave corresponding tothe most critical flammability conditions mustbe parallel to the longest dimension. Eachspecimen must be supported vertically. Thespecimen must be exposed to a Bunsen or Tir-ril burner with a nominal 9 · 5 mm (3/8-inch)I.D. tube adjusted to give a flame of 38 mm(11/8 inches) in height. The minimum flametemperature measured by a calibrated thermo-couple pyrometer in the centre of the flamemust be 843◦C (1550◦F ). The lower edge ofthe specimen must be 19 mm (3/4-inch) abovethe top edge of the burner. The flame mustbe applied to the centre line of the lower edgeof the specimen. For materials covered bysub-paragraph (a)(1)(i) of Part I of this Ap-pendix, the flame must be applied for 60 sec-onds and then removed. For materials coveredby sub-paragraph (a)(1)(ii) of Part I of thisAppendix, the flame must be applied for 12seconds and then removed. Flame time, burnlength, and flaming time of drippings, if any,may be recorded. The burn length determinedin accordance with subparagraph (7) of thisparagraph must be measured to the nearest 2·5mm (tenth of an inch).

(5) Horizontal test. A minimum of threespecimens must be tested and the results aver-aged. Each specimen must be supported hor-izontally. The exposed surface, when installedin the aircraft, must be face down for the test.The specimen must be exposed to a Bunsen orTirrill burner with a nominal 95 mm (?-inch)I.D. tube adjusted to give a flame of 38 mm(11/2 inches) in height. The minimum flametemperature measured by a calibrated thermo-couple pyrometer in the centre of the flamemust be 843◦C (1550◦F ). The specimen must

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be positioned so that the edge being tested iscentred 19 mm (3/4-inch) above the top of theburner. The flame must be applied for 15 sec-onds and then removed. A minimum of 25 cm(10 inches) of specimen must be used for timingpurposes, approximately 38 mm (11/2 inches)must burn before the burning front reaches thetiming zone, and the average burn rate mustbe recorded.

(6) Forty-five degree test. A minimum ofthree specimens must be tested and the resultsaveraged. The specimens must be supportedat an angle of 45◦ to a horizontal surface. Theexposed surface when installed in the aircraftmust be face down for the test. The speci-mens must be exposed to a Bunsen or Tirrillburner with a nominal 3/8-inch (9 · 5 mm) I.D.tube adjusted to give a flame of 38 mm (11/2

inches) in height. The minimum flame temper-ature measured by a calibrated thermocouplepyrometer in the centre of the flame must be843◦C (1550◦F ). Suitable precautions must betaken to avoid draughts. The flame must beapplied for 30 seconds with one-third contact-ing the material at the centre of the specimenand then removed. Flame time, glow time, andwhether the flame penetrates (passes through)the specimen must be recorded.

(7) Sixty-degree test. A minimum of threespecimens of each wire specification (make andsize) must be tested. The specimen of wire orcable (including insulation) must be placed atan angle of 60◦ with the horizontal in the cabi-net specified in sub-paragraph (3) of this para-graph with the cabinet door open during thetest, or must be placed within a chamber ap-proximately 61 cm (2 feet) high by 31 cm by 31cm (1 foot by 1 foot), open at the top and at onevertical side (front), and which allows sufficientflow of air for complete combustion, but whichis free from draughts. The specimen must be

parallel to and approximately 15 cm (6 inches)from the front of the chamber. The lower endof the specimen must be held rigidly clamped.The upper end of the specimen must pass overa pulley or rod and must have an appropriateweight attached to it so that the specimen isheld tautly throughout the flammability test.The test specimen span between lower clampand upper pulley or rod must be 61 cm (24inches) and must be marked 20 cm (8 inches)from the lower end to indicate the central pointfor flame application. A flame from a Bunsenor Tirrill burner must be applied for 30 secondsat the test mark. The burner must be mountedunderneath the test mark on the specimen, per-pendicular to the specimen and at an angle of30◦ to the vertical plane of the specimen. Theburner must have a nominal bore of 9 · 5 mm(3/8-inch) and be adjusted to provide a 76 mm(3-inch) high flame with an inner cone approxi-mately one-third of the flame height. The min-imum temperature of the hottest portion of theflame, as measured with a calibrated thermo-couple pyrometer, may not be less than 954◦C(1750◦F ). The burner must be positioned sothat the hottest portion of the flame is appliedto the test mark on the wire. Flame time,burn length, and flaming time of drippings, ifany, must be recorded. The burn length deter-mined in accordance with subparagraph (8) ofthis paragraph must be measured to the near-est 2 ·5 mm (tenth of an inch). Breaking of thewire specimens is not considered a failure.

(8) Burn length. Burn length is the dis-tance from the original edge to the farthestevidence of damage to the test specimen dueto flame impingement, including areas of par-tial or complete consumption, charring, or em-brittlement, but not including areas sooted,stained, warped, or discoloured, nor areaswhere material has shrunk or melted away fromthe heat source.

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Appendix 3: Most relevant methods of compliance for FAR/CS §25.853 proposedin FAA draft policy memo ANM-115-09-XXX

PartRef.Nb.

Feature/Construction

Similarity

Part 1 2Thicknessranges

Data from testing a thinner construction substantiates athicker construction made of the same materials.

Part 1 13 TextureData from testing one texture of a decorative type substan-tiates a panel with the same decorative type with a differenttexture.

Part 1 16Aluminum/Steel/Titanium

Unless they contain magnesium or magnesium alloys, un-finished metal parts do not require testing. Finishedmetal parts do not require testing provided : standard*paint/finishes are used and the parts do not contain magne-sium or magnesium alloys.

Part 2 3 Core, densityData from testing a lower density honeycomb core substan-tiates a higher density honeycomb core[...].

Part 2 4 Core, cell sizeData from testing ANY core cell size/shape substantiatesother core sell sizes/shapes of the same material[...].

Part 2 5Paint/inksystems

Test of one color substantiates other colors of the samepaint/ink system and the unpainted panel.

Part 2 15Syntheticleather/suede

Data from testing one synthetic leather/suede material sam-ple will substantiate other colors of the same material.

* Standard paint/finishes are defined as inorganic finishes, epoxy primers and topcoats, urethanetopcoats, and corrosion inhibiting dry films.

Appendix 4: Photographs of the samples manufacturing process relative to theFBL preliminary campaign

(a) Cutting of large pieces (b) Preparation of the assemblies

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(c) Application of the glue on the panels(d) Drying after application of the glue on alllayers

(e) Laying of the laminate (f) Drying of the painted panels

(g) Cutting of the samples (h) Packing and expedition

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Appendix 5: Results of the FBL preliminary test campaign

Figure 1: Average values of the measured burn length

Figure 2: Average values of the measured extinguishing time

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Appendix 6: Photographs of the burnt samples relative to the FBL preliminarycampaign

The two samples to the left are without mica paper, while the two to the right do have it.

Composite based assemblies

(a) Composite-Laminate (b) Composite-Fabric

(c) Composite-Paint (d) Composite-Synthetic leather

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Wooden assemblies

(e) Wood-Laminate (f) Wood-Fabric

(g) Wood-Paint (h) Wood-Synthetic leather

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