EngineCleaningAndVolcanicAsh Intern

R A P P O R T D E S S T A G E T E C H N I Q U E

I N T E R N S H I P T E C H N I C A L R E P O R T

ENR0090-D Ce document est la proprit de la socit Turbomeca. Il ne peut tre communiqu ou reproduit sans son autorisation Le texte original de ce cahier des charges, crit en franais, fera fo i en cas dinterprtat ion et/ou de lit ige entre les part ies. This document is the property of Turbomeca and may not be copied, used or communicated without Turbomecas authorization In case of misinterpretat ion and/or dispute, the orig inal text of th is specificat ion, written in French, will be authoritative as between the parties.

M E T T E U R / F R O M : U N H E L K A R V A I B H A V

CLEANING, WASHING AND RINSING OF TURBOSHAFT ENGINES

COMPARISON OF TURBOMECA PROCEDURES,

CUSTOMER STUDIES

AND

THE PROBLEM OF VOLCANIC ASH

R A P P O R T D E S T A G E T E C H N I Q U E INTERNSHIP TECHNICAL REPORT


CONTENTS 1 Purpose __________________________________________________ 6 2 Introduction _______________________________________________ 6 3 Approach towards Analysis __________________________________ 6 4 Turboshaft Engines_________________________________________ 7

4.1 Basic Architecture ________________________________________________________ 7 4.2 Operation ________________________________________________________________ 8 4.3 Categories _______________________________________________________________ 9 4.4 Arrius __________________________________________________________________ 10 4.5 Arriel___________________________________________________________________ 10 4.6 Makila __________________________________________________________________ 11 4.7 Comparative Study _______________________________________________________ 12 4.7.1 Engine Application___________________________________________________ 12 4.7.2 Performance Parameters______________________________________________ 13 4.7.3 Physical Parameters _________________________________________________ 14 4.7.4 Engine Architecture__________________________________________________ 14 4.7.5 Cleaning Related Parameters __________________________________________ 16

5 Cleaning, Washing and Rinsing Turbomeca Procedures________ 18 5.1 Nomenclature ___________________________________________________________ 18 5.2 Rinsing_________________________________________________________________ 20 5.2.1 Generic Procedure___________________________________________________ 20 5.2.2 Difference Between Engines___________________________________________ 21 5.2.3 Comments__________________________________________________________ 22 5.2.4 Rinsing Products ____________________________________________________ 22 5.3 Washing ________________________________________________________________ 23 5.3.1 Generic Procedure___________________________________________________ 23 5.3.2 Difference Between Engines___________________________________________ 23 5.3.3 Comments__________________________________________________________ 24 5.3.4 Washing Products ___________________________________________________ 25 5.4 Cleaning________________________________________________________________ 26 5.4.1 Generic Procedure___________________________________________________ 26 5.4.2 Difference Between Engines___________________________________________ 27 5.4.3 Comments__________________________________________________________ 28



5.4.4 Cleaning Products ___________________________________________________ 29 5.5 Frequency ______________________________________________________________ 30 5.5.1 General Cases ______________________________________________________ 30 5.5.2 Specific Cases ______________________________________________________ 31 5.6 Tools___________________________________________________________________ 31 5.7 Products used ___________________________________________________________ 33 5.8 Cautions - Health, Safety, Environment ______________________________________ 35

6 Cleaning, Washing and Rinsing Customer Studies ____________ 36 6.1 Australia________________________________________________________________ 37 6.2 North America ___________________________________________________________ 38 6.3 North Sea _______________________________________________________________ 39 6.4 Asia Pacific _____________________________________________________________ 41 6.5 Summary _______________________________________________________________ 42

7 Cleaning, Washing and Rinsing Experiences Outside Turbomeca 43 7.1 Nomenclature ___________________________________________________________ 43 7.2 Literature Survey_________________________________________________________ 44 7.2.1 Introduction ________________________________________________________ 44 7.2.2 Evolution___________________________________________________________ 44 7.3 Summary _______________________________________________________________ 46

8 Volcanic Ash - Introduction _________________________________ 47 8.1 Fundamentals ___________________________________________________________ 47 8.1.1 Volcanoes __________________________________________________________ 47 8.1.2 Volcanic Eruptions___________________________________________________ 48 8.1.3 Volcanic Ash________________________________________________________ 49 8.2 Volcanic Ash and AVIATION _______________________________________________ 50 8.2.1 Background ________________________________________________________ 50 8.2.2 Effect on Aviation____________________________________________________ 51 8.2.3 Effect on Aircrafts ___________________________________________________ 52 8.2.4 Notifications and Warnings____________________________________________ 55 8.2.5 Fly Zones __________________________________________________________ 56

9 Volcanic Ash and ENGINES _________________________________ 58 9.1 Major Effects ____________________________________________________________ 58 9.2 Ash Ingestion An Estimate _______________________________________________ 59 9.3 Other Contaminants ______________________________________________________ 61



9.3.1 Sand ______________________________________________________________ 61 9.3.2 Chemical Environment _______________________________________________ 62 9.3.3 Comparison With Volcanic ASH________________________________________ 62 9.4 Engine Maintenance ______________________________________________________ 63 9.4.1 Current Procedures __________________________________________________ 63 9.4.2 Service Bulletins ____________________________________________________ 64 9.4.3 Suggestions Engine Cleaning ________________________________________ 66 9.4.4 Suggestions Service Bulletins________________________________________ 67 9.5 Long Term Solutions _____________________________________________________ 69 9.5.1 Filters _____________________________________________________________ 69 9.5.2 Electromagnetic Properties ___________________________________________ 69 9.5.3 Development of Solutions_____________________________________________ 69 9.5.4 Engine Design ______________________________________________________ 70 9.5.5 Summation _________________________________________________________ 70

10 References _______________________________________________ 70



1 PURPOSE The study presented on the topic of Cleaning, Washing and Rinsing of Turboshaft Engines: Comparison of Turbomeca Procedures, Customer Studies and the problem of Volcanic Ash is performed as requirement towards the Internship (Stage) at the TURBOMECA Support Department in Turbomeca, Tarnos under the guidance of M. PEROT Philippe. The study aims to realign the current knowledge on Engine Cleaning and provide solutions for the problem of Volcanic Ash.

Turbomeca documents (Training and Maintenance Manuals) and studies from open literature (research publications and the internet) were the primary resources used for the study. Timely suggestions and advice from the Mentor, Training Centre and Engineers at the Support department in Tarnos were illuminating as well as useful, and I would like to thank them for the same. Lastly, I would like to express my gratitude towards the Turbomeca and the Indian Institute of Technology, Bombay for providing the opportunity and resources to carry out the following study.

2 INTRODUCTION To maintain the operation of engines in variety of conditions proper maintenance is essential. The operations of Rinsing, Washing and Cleaning are one of the primary tasks used in maintainability, in order to prevent corrosion and deterioration of engine, and performance recovery, in order to recover efficiency, torque margin and temperature margins, of Turboshaft Engines.

Rinsing (Rincage), Washing (Lavage) and Cleaning (De-crassage) though seemingly trivial tasks affect the performance as well as the maintenance cost of an Engine very drastically. The operation of Rinsing, Washing and Cleaning becomes even more important to Helicopters due to the specific nature of their operations; such as, near surface operations in sandy, saline or polluted atmosphere, landing/take-off in unpaved (hence, dust-prone) areas, and last but not the least the on-going problem of Volcanic Ash (the Icelandic eruptions of Eyjafjallajokull).

Based on a detailed literature survey and engineering analysis, this document intends to underline the importance of Rinsing, Washing and Cleaning procedures specifically for Helicopter (Turbo-shaft) Engines. Finally, this document presents an overview of some approaches, validation of the current procedures and a few solutions with regards to the protection and maintenance of Turbo-shaft engines affected by the Volcanic Ash.

3 APPROACH TOWARDS ANALYSIS A top-down approach was adopted in the overall analysis wherein the work was divided into the following broad sections, namely,

Comparative analysis of various TURBOMECA Turbo-shaft engines Various aspects of Rinsing, Washing and Cleaning of Turbo-shaft engines

o Validation of the current Turbomeca procedures o Comparison of the current procedures for different engine families

( ranging from MTOW of 2-3 Tonnes to that of 11-12 Tonnes ) o Customer Experiences o Compilation and Survey of other procedures (apart from that of Turbomeca)

Effect of Volcanic Ash on Turbo-shaft Engines Solutions for Performance Recovery and Operations of Engines affected by Volcanic Ash



4 TURBOSHAFT ENGINES Turboshaft engines are the gas-turbine engines that convert the chemical energy in fuel and air into mechanical energy on a shaft. The turbo-shaft engines find application in various industries apart from aviation. The mechanical energy on the shaft can be used for various purposes, such as, helicopter rotors, electric generator and hydraulic pumps.

FIGURE 1: ARRIEL A Free-Turbine Turboshaft Engine

First, basic architecture and operation of a turboshaft engine is described. Thereafter, detailed information is documented for the specific TURBOMECA engines under consideration, and a comparative analysis has been made.

NOTE: Although, this document is focused on application of turbo-shaft engines on Helicopters; it should be borne in mind that the problems (and consequently their solutions) related to Rinsing, Washing and Cleaning of similar nature also arise in land and marine turbines, and that the experience on land and marine turbines could be used for improving the Rinsing, Washing and Cleaning for helicopter applications.

4.1 BASIC ARCHITECTURE

Different types of turbo-shaft engines exist with differing architecture, technology and application, but few basic components are found in all the turboshaft engines. These include:

Air Intake Compressor Section

o Axial Compressor, and/or o Centrifugal Compressor

Combustion Chamber Turbine Section Output Power Shaft Exhaust System



FIGURE 2: Fundamental parts of a free-turbine Turbo-shaft engine

A shaft connects the compressor section to the turbine section; which is required since the turbine section provides the energy to drive the compressor section. The following figure shows the main components of a turboshaft engine. These components are present on all the turboshafts but their position, number and architecture might vary.

4.2 OPERATION

The engine provides power by transforming the energy in the ambient air and fuel into the mechanical energy on the shaft. The process of this conversion consists of the following steps:

FIGURE 3: Main Operating Phases of Gas Turbine Engines Admission

o Ambient air is admitted through the Air Intake Compression

o The ambient air is then compressed by the Compressors in the system o The air is taken to a very high pressure



Combustion o The compressed air is combined with the fuel o The gas mixture is burnt in the Combustion Chamber to produce thermal energy o This also results in a very high temperature o The performance of gas-turbine engines is usually limited by the material properties

of the Combustion chamber Expansion

o The hot gas expands in this section and drives the Turbines o The gas pressure and temperature drops o The thermal energy is converted into shaft mechanical energy

Power transmission o The power is transmitted to the output shaft o Generally, a reduction gearbox is used to reduce the angular speed of the output

shaft

4.3 CATEGORIES

As there are various types of helicopters, there are various types of engines which provide them with power. The turboshaft engines are mainly of two types:

Single shaft turboshaft engines o The compressor-turbine shaft in directly connected to the output shaft o Has a robust and simplistic design o Suitable for single-engine helicopter operation

Free Turbine turboshaft engines o Has two separate rotating assembly, which may or may not operate in the same

direction The first assembly is called the Gas Generator, it is the compressor-

turbine shaft The second assembly is the one that drives the Power Turbine (also

known as the free turbine) and is connected to the output shaft o Found in various configurations, such as

Rear power drive Front power drive

Through an internal/coaxial shaft Through an external shaft

o Offers greater flexibility and can be used for twin-engine operations

Apart from their architecture, the turboshaft engines can also classified by their size, output power, design of intake, etc.

In this document only free-turbine turboshaft engines are considered. The following engines of varying architectures are chosen for analysis, namely:

Arriel 1 S1 Arriel 2 S2 Arrius 2 B2 Makila 2 A

The said engines are chosen since they span the range of modular free turbine turboshaft engine and provide power to various helicopters ranging from a MTOW of 2 to 11 tons.



4.4 ARRIUS

Arrius is a family of free turbine turboshaft engines with an integral reduction gearbox and front power drive with a power output of 357 530 kW. The engine family is specifically designed to power light single and light twin engine helicopters in the 2-3 ton range.

The engine family has the smallest engines of the Turbomeca Turboshaft family of engines, and hence has the least power output. The engine though modular, consists of only two modules, owing to its size and application. In comparison with the other engines it is void of any axial compressor stage, and relies totally on the centrifugal compressor for developing the pressure required for combustion.

The variant Arrius 2 B2 was released in the year 2002, and is used to power the Eurocopter helicopter EC135 with a MTOW of 2910kg.

FIGURE 3: Engine Architecture Arrius 2B 2

4.5 ARRIEL

Arriel is a family of free turbine turboshaft engines with external power transmission shaft and forward power drive and a power output of 478 704 kW. The engine family has produced 9000 engines till date and has flown for more than 30 million hours in over 100 countries. Out of its 28 variants we shall be discussing two, namely, Arriel 1 S1 and Arriel 2 S2.

It is one of the most used engines of the Turbomeca family and was introduced into service as early as 1977. It has been used for over 15 helicopter types in 110 countries and due to continuous evolutions and modification is still being used for a lot of applications.

The variant Arriel 1 S1 powers the twin engine medium lift Sikorsky S76A+, S76A++ and S76C helicopters, and is developed for off-shore missions.



FIGURE 4: Engine Architecture Arriel 1S 1

The variant Arriel 2 S2 was certified in 2005 and powers the twin engine medium lift Sikorsky S76C++ helicopters.

FIGURE 5: Engine Architecture Arriel 2S 2

4.6 MAKILA

Makila is a family of free turbine turboshaft engines with a rear direct power drive and with a power output of 1300 1600 kW. Due to the higher power output, owing to its size and design, the Makila family is used to power the heavier helicopters. Another, salient feature of Makila engines is the rear power drive allowing engine installation in front of the rotor and drastically reducing the intake losses. The variant Makila 2 A certified in 2004, powers the military helicopter Eurocopter EC 725 and its civil variant Eurocopter EC 225.



FIGURE 6: Engine Architecture Makila 2A

4.7 COMPARATIVE STUDY

This section enlists a comparative study of variety of parameters of the engines discussed above. The section is divided into five parts, each part comparing parameters of different sub-systems in regard to turboshaft engine.

4.7.1 ENGINE APPLICATION

Firstly, we have an overview of the application of the said engines on various helicopters, in order to have an estimate of performance and capability of the engines.

Arriel 1S 1 Arriel 2S 2 Makila 2A Arrius 2B 2

Helicopters Sikorsky S 76 A+ Sikorsky S76A++ Sikorsky S 76 C

Sikorsky S 76 C++

(twin engine)

EurocopterEC725 EurocopterEC225

(twin engine)

Eurocopter EC 135

(twin engine) MTOW (kg) - 5306 11200 2910 Introduction 1986 2004 2003 2002

TBO 3000 4000 3500 3500

TABLE 1: Applications Comparative Study of free-turbine Turboshafts

We can see that the Makila family powers the heaviest of the aircraft and requirements for the same shall be reflected in its physical and performance parameters.

The value of TBO(in hours) is comparable for all of the engines, and continuous efforts are made in order to increase its value.

All the Type 2 engines are relatively recent and hence use newer technologies and provide better performance.



4.7.2 PERFORMANCE PARAMETERS

Arriel 1S 1 Arriel 2S 2 Makila 2A Arrius 2B 2 MTOP (kW) 575 688 1563 479

AEO MCP (kW) 541 621 1395 439 Power/DryMass 4.29 4.5 5 3.85

Pow/G (Specific Power) 216.4 214.13 219.34 211.05

SFC - 390 280 - EGT ( C ) 600 670 550 700

TBO (hours) 3000 4000 3500 3500

TABLE 2:Performance Parameters Comparative Study of free-turbine Turboshafts NOTE: All the parameters are listed at their respective standard conditions

Owing to its size Makila produces the highest power, over thrice that of the Arrius Power/Dry Mass

o Power output per unit of mass of the engine This parameter indicates the amount of Power produced per unit of dry mass of the engine and has the units of kW/kg

o Ideally, the user would want this parameter to be as high as possible o It is highest for Makila 2A (~5) and lowest for Arrius 2B2 (~3.85) o This metric indicates that As the size of the engine grows the extra weight

required to produce the marginal power reduces" o This result is intuitive since after the basic weight for engine has been

accounted for (which is necessary in all the engines) the extra weight for one stage of compressor would produce enormous increase in output power

o However, care should be taken that the trend observed might not be universal Shall depend heavily on the design of the engines The trend might show a global peak after which adding extra

compressors will not result in increase of Power/Dry Mass ratio Power/G

o Power output per unit of air flow into the engine This parameter indicates the amount of power generated by the engine when the mass flow is 1 kg/s

o Units: kW*s / kg OR kJ/kg o This normalized metric gives a way of comparing efficiency and technology of

various engines o The value of this parameter is in the same range for all the engines indicating

some similarity in design and efficiency SFC

o Specific Fuel Consumption Quantity of fuel necessary to produce one kW of power per unit of time (usually hour)

o Values of SFC are dependent on the engine design which is in turn dictated by the requirement from helicopter. A lower value of SFC is always preferred.

EGT o Exhaust Gas Temperature Indicates the temperature of the exhaust gases o It should be as low as possible for two reasons



Higher temperature indicates more energy can be extracted from the flow, i.e. the engine is performing at lesser efficiency

For environmental reasons (Green engines) o Arrius has the highest EGT of 700 C

4.7.3 PHYSICAL PARAMETERS

Arriel 1 Arriel 2 Makila 2 Arrius 2 Variant S 1 S 2 A B 2

Type Free Turbine Free Turbine Free Turbine Free Turbine Power Drive Forward Forward Rear Forward (IRG)

Modules 5 5 4 2 Dry Mass (kg) 126 138 279 114

1166 1166 2115 1158 465.5 465.5 785 518 Dimension (mm) 609 609 668 690

TABLE 3: Physical Characteristics Comparative Study of free-turbine Turboshafts

All the engines are modular free turbine turboshaft engines Although, all the engines are modular the number of modules vary - wherein Arrius

family has as low as 2 modules and Arriel family has 5 modules Makila 2A

o Is the largest in terms of both the size and weight o Differs in the overall layout as it has a rear power drive: this permits

Engine installation in front of the rotor and Significantly reduces pressure loss due to air intake.

Arrius 2B 2 o Is the smallest and the lightest, which reflects in its capacity and MTOP.

Arriel o Dimensions of Arriel 1S1 are given different on the Turbomeca Site and Training

Manual Different conventions for measuring the length have been observed.

4.7.4 ENGINE ARCHITECTURE

Next, we compare the basic engine architecture of the four engines: Air Intake

o All the engines have an annular air intake o Engines except Arrius have a dynamic intake

Which means that they have a frontal intake Even when the engine is not switched on there is air flow through the

engine Arrius on the other hand due to installation constraints does not have a

frontal intake o G, Air Mass flow (kg/s)

Amount of air introduced into the engine per unit of time Is highest for the Makila engines and least for Arrius



Arriel 1S 1 Arriel 2S 2 Makila 2A Arrius 2B 2

Intake Dynamic, Annular Dynamic, Annular

Dynamic, Annular Annular

G 2.5 2.9 6.36 2.08 Axial Compressor

Stages 1 1 3 Nil Pressure Ratio 1.5 1.6 2.65 Not Applicable

Material Titanium Alloy Titanium Alloy Titanium Alloy Not Applicable Centrifugal Compressor

Pressure Ratio 5.4 5.12 4.25 9.1 Material Titanium Alloy Titanium Alloy Titanium Alloy Titanium Alloy

Diffuser Stages 2 2 2 2 Combustion

Chamber

Geometry Annular Annular Annular Annular Fuel Injection Centrifugal Centrifugal Centrifugal Reverse Flow Max. Temp. 2500 2500 2500 2500

Gas Generator Turbine

Geometry Axial Axial Axial Axial Stages 2 1 2 1

52000 52110 33200 44038 N1 (100%) RPM ACW ACW ACW CW

Power Turbine Geometry Axial Axial Axial Axial

Stages 1 1 2 1 41600 39095 22962 54117 N2 (100%) RPM CW CW ACW ACW

Power Shaft Drive Front Front Rear / Bendix Front NR RPM 6000 6000 22962 5898

TABLE 4: Engine Architecture Comparative Study of free-turbine Turboshafts

Axial Compressor o Is absent in Arrius engine o Makila has a 3 stage axial compressor with a pressure ratio of 2.65

Centrifugal Compressor o Arrius has the highest pressure ratio of 9.1 as whole of the compression is

done by the centrifugal compressor o Both the Axial and Centrifugal compressor are made of Titanium alloys o Two divergent diffuser stages are present after the centrifugal compressor in

order to increase the pressure, decrease the velocity and straighten the flow



o Overall pressure ratio (across both the compressors) is highest for Makila (~11.26) and least for Arriel 1 (~8.1)

Combustion Chamber o Arrius has fuel injection with reverse flow; while Arriel and Makila have

centrifugal fuel injection o This design difference is reflected in various other engine parameters

Size of the engine Turbine Entry Temperature Exhaust gas temperature

o The maximum temperature in the engine is at the Combustion Chamber and is 2500C for all the engines. This is due to the mate rial limitations which are present for all type of engines and limit their design and performance

Gas Generator Turbine o Arriel 1S1 and Makila 2A have two stages of Gas Generator Turbine while

Arriel 2S2 and Arrius 2B2 have single stage Gas Generator Turbine This is one of the main difference in the architecture of Arriel 1S1 and

2S2 o Due to the velocity vector triangles Arrius gas generator turbine moves in CW

(seen from behind) while for the rest of engines it moves in ACW direction o N1 denotes the rotation speed of Gas Generator section is highest for Arriel

and least for Makila

Power Turbine o Makila being the largest engine has two power turbine stages o Arrius has the highest power turbine speed while Makila has the least

Power Shaft Drive o Speed of the power shaft drive is very high for Makila 2A, this is because of the

fact that the Makila has a rear direct power drive and no reduction gear box o After reduction gearbox the rotation speed of the engine rotors is comparable

for various helicopters and is in the range of 5000-7000 RPM

4.7.5 CLEANING RELATED PARAMETERS

Since, the main focus of this study is to analyze Cleaning procedures of the said engines; we shall see in brief some parameters related to the engine cleaning. The operation of Cleaning is covered in more detail in further sections.

Arriel 1S 1 Arriel 2S 2 Makila 2A Arrius 2B 2 In-built Washing

System No No Yes Yes

Intake Protections

Sand Filter/EAP/Vortex filter/Barrier filter (Optional)

Barrier Filters/ EAP (optional) Inlet Grid

Related Problems

Sand Accumulation in Hollow Shaft and Cleaning of Turbine Section

Cleaning of Turbine Section

TABLE 5: Cleaning Parameters Comparative Study of free-turbine Turboshafts



Washing System o An inbuilt washing/cleaning manifold exists for the engines Makila and

Arrius 2B2 o Arriel on the other hand has washing systems based on the helicopter,

details of which can be found in the Aircraft Maintenance Manual

Intake Protections o For the Arrius engines an Inlet Grid is present in order to protect the engines

from Foreign Object Damage o Makila and Arriel engines have an option of installing Sand Filters or Barrier

Filters to protect the engine and filter the incoming air flow. o These measures are particularly important and sometimes necessary for

flights in sand-laden or volcanic ash affected atmosphere.

Cleaning Related Problems o Cleaning, Washing and Rinsing are scheduled maintenance task to recover

performance of the engine, but at times they are used in case some specific problem arises

o Arriel engines consist of a hollow shaft which might get accumulated with sand or dirt depending on operating conditions and can cause vibration. To restore the performance cleaning of hollow shaft is to be performed. However, it should be noted that this is not a Line 1 maintenance task.

o Makila engines because of their length might encounter some problems in cleaning of aft stages of the compressor and turbine stages

o Apart from this cleaning operation is used in order to recover T4.5 margin and/or Torque margin based on Power Assurance Check

Now, with the basic knowledge of turboshaft engines, we move on to the analysis of Cleaning, Washing and Rinsing for Turboshaft Engines.



5 CLEANING, WASHING AND RINSING TURBOMECA PROCEDURES The procedures of Cleaning, Washing and Rinsing are some of the most important and effective tasks for performance recovery of engines. The tasks are mandatory for all sorts of gas turbine engines, land-based or aviation, turbojet or turbofan, and so on. In this section, we shall be concentrating on the specific procedures for Turboshaft engines specified by Turbomeca, followed by their comparison and analysis with external Cleaning, Washing and Rinsing procedures in the next section. Furthermore, the cleaning of engines is performed in all levels of maintenance, albeit with varied sophistication and technique; here we shall be specifically focusing on procedures specified for 1st Line Maintenance.

Cleaning, Washing and Rinsing are very broad and generic terms, hence, numerous definitions and interpretations can be derived, making the technical communication and any further discussion not just confusing but at times misleading. Thus, at the outset, we shall get introduced to the nomenclature and definitions of the seemingly-trivial but nonetheless important operations of Cleaning, Washing and Rinsing in context of turboshaft engines.

Figure 7: Typical Equipment for Compressor Cleaning

This section is heavily derived from the information obtained from Turbomeca Maintenance Manuals and Technical Specifications, and from the vast amount of data in these publications relevant information has been extracted, analyzed and compiled. In this section, firstly we see the existing Turbomeca procedures for Rinsing, Washing and Cleaning, respectively. For each of the process a generic description is provided followed by detailed comparison of the process for the three turboshaft engines, namely, Arriel 2S2, Arrius 2B2 and Makila 2A. Each section concludes with comments on ambiguities in the current procedures and suggestions for improvements.

Lastly, all the information related to operations of Cleaning, Washing and Rinsing, i.e. details about necessary Cleaning Products, Safety, Frequencies, Tools and Equipments, is compiled.

With all this information, we shall be equipped with ample background and clarity of jargon to understand the evolution, comparison and analysis of the Cleaning, Washing and Rinsing procedures apart from that of Turbomeca, which are covered in the next section.

5.1 NOMENCLATURE

Cleaning, Washing and Rinsing are words that are so similar that without having a formal technique definition it is difficult if not impossible to carry forward any analysis. The Oxford dictionary defines the three processes as follows



Cleaning getting rid of dirt, impurities and extraneous substances Washing cleaning with water Rinsing washing quickly with water and no soap

One can quite easily see that the generic definitions of these processes are not enough and hence in context of maintenance of engines we define them as follows

Cleaning Operation to clean the engine and remove corrosive deposits using an aqueous solution of concentrated cleaning product (15 to 25%).

Washing Operation to remove corrosive, crystallized salt deposits by an aqueous solution of weakly concentrating cleaning product (2 to 5%)

o Washing for engine running, operation carried out with the engine running o Washing during ventilation/Cranking, operation carried out with the engine

shutdown (with the starter-generator). Rinsing Operation to remove salt deposits using only water (and an anti-freeze if

necessary)

Similarities exist between the technical definitions and the dictionary meanings, but some additional conditions are imposed on each operation differentiating it from its generic description. Some of the differences between the processes are listed as follows:

Cleaning Washing Rinsing Tools Pressure Generator-Nozzle Y Y Y Washing System Y Y Y Products Required Distilled Water Y Y Y Chemicals Y Y N Percentage of Chemicals ~20 ~2 0 Periodicity Daily - Y Y Weekly Y Y Y Performance Recovery Y Y Y Effluent Removed Salt - Y Y Dirt Y - - Procedure Engine Running N Y Y Cranking/Ventilation Y Y Y

Table 6: Comparison of Cleaning, Washing and Rinsing

The above table lists some of the main parameters of interest in the operations related to engine cleaning. In the next sections, we shall see the same parameters in more detail and comparison of the processes for engines of varying architecture.



5.2 RINSING

Rinsing is the process of removing salty deposits in the gas path of an engine using only water (and anti-freeze products depending on the ambient temperature). It is the most basic of the task of cleaning, washing and rinsing; and hence is usually recommended to be done daily after the last flight of the day (EDF).The task usually can be performed either with the engine running or by cranking. Rinsing by cranking is recommended as it is more efficient, but operators might prefer rinsing with the engine running as it is less time-consuming.

5.2.1 GENERIC PROCEDURE

Procedure for Rinsing is specific to each engine, but there are a few common tasks that are performed in rinsing of all engines; the specific numeric parameters (amount of fluid, time required, etc.) usually vary. The procedure of Rinsing can be divided into the following basic steps:

Preparation of Rinsing mixture o Quantity of mixture o Percentage of Constituents ( Demineralised Water and Anti-Icing Agent) o Homogenization

Aircraft Settings o Blanking of Bleed Valve o Closing all the aircraft manufacturer bleed valve

Tool Settings o Connection of the tool o Pressure/Flow settings of the tool

Injection of Rinsing Mixture o Cranking

Number of times Amount of time Flow speed

o Engine Running N1 specification Amount of time Flow Speed

Removal of Equipment o Of tools o Of blanks on valves

Drying of the engine o Time o Procedure o Exceptions

Post-maintenance Procedure o Internal Protection o External Protection

The factors listed in italics above are the specific numerical parameters which differ from engine to engine and are based on size of the engine, number of compressor stages and properties of the engine washing system.



5.2.2 DIFFERENCE BETWEEN ENGINES

Now we tabulate the differences between the specified procedures for Rinsing for the three engines:

Arriel 2S2 Makila 2A Arrius 2B2 Rinsing Mixture

Quantity Necessary 7 litre 3.5 litre Anti-icer not mentioned Demineralised Water Not Mentioned Consumables

Anti-Icer Percentage Not Mentioned As per CCT_00800_C As per CCT_00800_C

Homogenization Not Mentioned Mentioned Mentioned Aircraft Settings

Manufacturer Air Bleeds Mentioned Mentioned Not Mentioned

Tools Settings Flow Speed 2-3 l/min 2-3 l/min Based on the Tool

Washing System Aircraft Based Present in Engine Present in Engine

Injection Engine Running Listed in MM Listed in MM Listed in MM

Cranking Not Listed in MM Listed in MM Listed in MM Drying

Time (seconds) 30 300 300 Not listed Internal Protection Internal Protection Additional

Provisions External Protection External Protection

Table 7: Comparison of Rinsing Procedure

As can be seen from the comparison, lot of differences exists in the numerical parameters related to Rinsing for various engines:

Quantity of Rinsing Mixture o Is least for Arrius and highest for Makila o Directly depends on the size of the engine

Settings of the Tools o Depending on the engine size, design of the tool and amount of flow

required differing flow speeds are specified for the engines Drying of the Engine

o Amount of time required for drying Arriel Engine is 30 seconds o Reason for the same is not known

Fluid Injection o Rinsing by Cranking (Ventilation) is not listed for Arriel engine



In the table, it can be seen that a lot of parameters are not clearly specified in the Maintenance Manuals; hence, next we list a few comments about the procedure and suggestions for the same.

5.2.3 COMMENTS

Due to various reasons such as translation, communication and human factor, any procedure is bound to have some ambiguities. Since, the procedures are used by customers in 1st Line maintenance it is of utmost importance, for safety of both the engine and the customer, that the procedures be verified and be made as clear and succinct as possible. This verification of procedures should be done not only for technical details but also for semantics (wordings) and clarity. Listed below are some such points in the procedure which might be confusing and can lead to an improper execution of the maintenance task:

Consumables o The products required for rinsing are not mentioned in consumables in

procedures of Arrius 2B2 and Arriel 2S2 o Although, they are mentioned separately elsewhere in the

procedure/Maintenance Manual Arriel 2S2

o Rinsing during Cranking not mentioned in the Maintenance Manual. This should be included

o Quantity and Percentage of Rinsing Mixture not mentioned in the Maintenance Manual

o Time for drying is drastically less. This might be a printing mistake. Makila 2A

o "CAUTION" for monitoring T4.5 mentions cooling the engine naturally, while in other engines ventilation can be used

Arrius 2B2 o Not mentioned in the procedure to close the aircraft manufacturer bleeds o Not mentioned in the procedure to monitor N1 drop

5.2.4 RINSING PRODUCTS

Rinsing means washing engine without any chemicals, yet based on ambient temperature following anti-freeze products must be used:

5.2.4.1 DESIGNATION

Anti-freeze product Water quality Distilled water Validated products

(recommended) Isopropyl alcohol Demineralised water Pure methanol

(AIR 3651) Products authorized for use

(replacement) 44/56 or 50/50 methanol/water

Minimum quality of water

Table 8: Rinsing Products



5.3 WASHING

Washing involves a desalting operation to remove Corrosive, Crystallized salt deposits by an aqueous solution of weakly concentrated cleaning product (2-5%). The procedure can be carried out in two ways, namely During Engine Running and During Ventilation/Cranking.


The generic procedure for Washing is similar to that of Rinsing, except for the fact that Cleaning Products to the tune of 2 to 5% are used while Engine Washing, while only distilled/demineralised water is used for Engine Rinsing.


Now we tabulate the differences between the specified procedures for Washing for the three engines:

Arriel 2S2 Makila 2A Arrius 2B2 Quantity Necessary 7 litre 3.5 litre

Washing Product Washing Product Not Mentioned Demineralised Water Demineralised Water Consumables

Anti-Icer Anti-Icer Percentage Ambiguity in % As per CCT_00800_C As per CCT_00800_C

Homogenization Mentioned Mentioned Mentioned Aircraft Settings


Tools Settings Flow Speed 2-3 l/min 2-3 l/min Based on the Tool

Washing System Aircraft Based Present in Engine Present in Engine Injection

Engine Running Listed in MM Listed in MM Listed in MM N1 68% Ground Idle Ground Idle

N1 drop 15% 10% Not Mentioned Cranking Listed in MM Listed in MM Listed in MM

2 ventilations of 20 seconds

One or more ventilations of

15 seconds

One or more ventilations of

15 seconds

1 rinsing of 15 seconds no rinsing no rinsing Drying

Time (seconds) 30(engine running) 300 (during ventilation) 300 300 Internal Protection Internal Protection Additional

Provisions Not listed for

Engine Running External Protection External Protection Table 10: Comparison of Washing Procedure



As mentioned earlier the procedures of Rinsing and Washing have a lot of similarity, in fact except for the difference in Washing Mixture and the procedure of Mixture Injection the methods are identical. For some engines, Rinsing hence is not defined separately and integrated into the procedures of Cleaning and Washing.

Quantity of Rinsing Mixture Settings of the Tools During Engine Running

o Value of N1 A minimum N1 has to be maintained for proper flow of air and

washing fluid during engine washing The value of N1 is engine specific Furthermore, a drop(10 15%) in this value of N1 can be

tolerated during the washing procedure During Cranking

o Number of ventilations Arriel - Two ventilations of 20 seconds each are specified Makila and Arrius One or more ventilation of 15 seconds

o Rinsing Literature indicates that it is a nice practice to rinse out the

chemicals after washing the engine This has been specified in Maintenance Manual for Arriel but not

Makila and Arrius Drying

o Arriel engines have different engine running time for drying based on the type of Washing

Engine running 30 seconds Ventilation 300 seconds

o Makila and Arrius on the other hand have same engine running time for drying of 300 seconds

5.3.3 COMMENTS

Listed below are some points and ambiguities in the procedure which might be confusing and can lead to an improper execution of the maintenance task:

Consumables o The products required for rinsing are not mentioned in consumables in

procedures of Arrius 2B2 and Arriel 2S2 o Although, they are mentioned separately elsewhere in the

procedure/Maintenance Manual Soaking

o CCT advises soaking of the engine with washing fluid for some time o But, in effect none of the engines Maintenance Manuals specify soaking

of the engine with washing fluid Arriel

o Ambiguity in the table listing Percentage of washing mixture o Ambiguity in what is meant by double the quantity of anti-icing

Volume of anti-freeze product can be doubled Percentage of anti-freeze product can be doubled

o Ventilation time is given as 20 seconds



This should be checked with starter generator limitation written in Aircraft Manual

o Note to Start injection at 10% N1 and continue till it drops below 10% not written. This should be included; otherwise there can be accumulation of cleaning products on the engine.

o Additional Procedures not mentioned Makila

o Number of Ventilations should be specified more clearly Arrius

o Number of Ventilations should be specified more clearly o Blanking of Aircraft Manufacturers Bleed not mentioned

5.3.4 WASHING PRODUCTS

Washing helps in quick removal of corrosive effluents. To achieve this certain chemicals are required. These chemicals should be tested and approved by the engine manufacturer before use, since they might have negative effects on the engine. TURBOMECA qualified washing products are tabulated as follows:

Cleaning product Anti-freeze product Water quality

ARDROX 6367 (Turboclean 2)

TURCOJET WASH K3 Validated products

(recommended) ZOK 27

Products authorized for use

(replacement) TURCO 6783-50

Isopropyl alcohol Distilled water Demineralised

water

Table 11: Washing Products

For proper and effective washing, it is also imperative to have proper concentration of the washing product, based on the following table

T0 Anti-freeze product

(*) % v/v

Cleaning product % v/v

Water % v/v

T0 5C (41F) 0 2 98 5C T0 -8C

(17.6F) 18 2 80 -8C T0 -24C

(11.2F) 33 2 65

Table 12: Proportion of Washing Mixture (*) If the methanol/water mixture is used, the proportions of anti-freeze product must be doubled.



5.4 CLEANING

Cleaning process is done in order to remove dirt and dust particles, insects and oil which have entered into the engine air path with the help of a degreasing liquid. This task is usually required to be performed weekly, but special circumstances may increase the frequency of the operation. In contrast to Rinsing and Washing this task can only be performed with the dry crank (ventilation) and is more time-consuming. Nevertheless, it is the most effective of all he three tasks and can fully recover engine performance, hence, is also suggested in case of failure in Power Assurance Check (negative Torque or T4.5 margin).


The generic procedure for cleaning is listed below; it is different mainly in the fact that it can be performed during ventilation (with dry crank) and requires soaking of the cleaning mixture for a long period of time (~20 minutes). The procedure of cleaning is concluded by that of rinsing.

Preparation of Rinsing mixture o Quantity of mixture o Percentage of Constituents ( Demineralised Water and Anti-Icing Agent) o Homogenization

Aircraft Settings o Blanking of Bleed Valve o Closing all the aircraft manufacturer bleed valve

Tool Settings o Connection of the tool o Pressure/Flow settings of the tool

Injection of Rinsing Mixture o Cranking

Number of times Amount of time Flow speed

o Engine Running N1 specification Amount of time Flow Speed

Soaking o Time of soaking o Required for proper cleaning of dirt

Rinsing o Described in Sec 5.2 o Done after Cleaning o In order to remove cleaning product

Removal of Equipment o Of tools o Of blanks on valves

Drying of the engine o Time o Procedure o Exceptions



Post-maintenance Procedure o Internal Protection o External Protection

The factors listed in italics above are the specific numerical parameters which differ form engine to engine and are based on engine parameters.


Arriel 2S2 Makila 2A Arrius 2B2 Cleaning Mixture

Quantity Necessary 4 litre 3.5 litre Cleaning Product Cleaning Product Not Mentioned

Demineralised Water Demineralised Water Consumables Anti-Icer Anti-Icer

Mentioned - but does not add up to 100%

Percentage Substitute Products - %

Not Mentioned

As per CCT_00800_C As per CCT_00800_C

Homogenization Mentioned Mentioned Mentioned Aircraft Settings


Cooling T4.5 100 C 70 C 70 C

Ventilation Allowed Ambiguity in MM Not Allowed Allowed

Tools Settings Flow Speed Not Mentioned Not Mentioned Based on the Tool

Washing System Aircraft Based Present in Engine Present in Engine

Procedure (Only Cranking)

Ventilations 2 One or More One or Two Soaking Time 10 minutes - twice 20 minutes Nil

Rinsing Not Explicitly Written Yes Yes Cranking Not Listed in MM Listed in MM Listed in MM Drying

Time (seconds) 300 Not Explicitly Written 300 Not listed Internal Protection Internal Protection Additional

Provisions External Protection External Protection

Table 13: Comparison of Cleaning Procedure



The following differences occur in the procedures of the three engines: Quantity of Rinsing Mixture

o Is least for Arrius and highest for Makila depending on the size Flow Speed

o Not mentioned for Arriel and Makila engines hence cannot be compared Drying of the Engine

o Is 300 seconds for all three engines o For Makila engines it is not explicitly written

Cooling Temperature (T4.5) o Arriel engines need to be cooled to 100C while th e Makila and the Arrius

engines need to be cooled to 70C Cooling through Ventilation

o Not allowed for Makila 2A o Allowed for Makila 1, Arriel and Arrius

Procedure for Cleaning o Number of ventilations are dependent on the Customer in Makila and Arrius o For Arriel, two ventilations are specified

Soaking o Two 10 minute soakings for Arriel Engine o One 20 minute soaking for Makila o No soaking specified for Arrius

Next we list a few ambiguities present in the procedure and suggestions for the same.

5.4.3 COMMENTS

Listed below are some comments about the procedure: Makila

o Quantity of Cleaning Product is 4 litres This is quite less in comparison with rinsing and washing

o Number of Crankings Should be specified clearly in the Maintenance Manual

o Drying of the engine Not written explicitly in the Maintenance Manual It is mentioned to Rinse the engine which also includes drying Nevertheless, should be mentioned explicitly so as to avoid any

confusion o Chapter on Cleaning Products The clause Refer to the specificities of the

engine should be removed Arriel

o Percentage of Cleaning Products Mentioned percentage doesnt add uo to 100 % For Substitute Products (Replacement/approved products) the

percentage of cleaning products are different as compared to Recommended Products This has not been mentioned

o Ambiguity/Mistake in a Note written about cooling the engine with ventilation NOTE: For a T0 of 15C (59F), it takes 50 minutes to decrease the

temperature to 100C (212F) or 25 minutes to decre ase the temperature to 100C (212F) if you do two ventilations of 30 seco nds, with 1 minute between them.



Two values of time (25 min and 50 min) given for same procedure Arrius

o Not mentioned to close aircraft manufacturers bleed valve o The process described for cleaning starts with the heading of Engine

Protection instead of Engine Cleaning

5.4.4 CLEANING PRODUCTS

5.4.4.1 DESIGNATION

The products approved or authorized for cleaning of engines are tabulated below. As far as possible only recommended products must be used, only in rare cases replacement products should be used.

Cleaning product Anti-freeze product Water quality ARDROX 6367 (Turboclean 2) ARDROX 6368 ready to use

(Turboclean 2 RTU) (**) TURCOJET WASH K3 ZOK 27(**)

Validated products (recommended)

RMC-G21(**)

Isopropyl alcohol Distilled water Demineralised

water

TURCO 4217 TURCO 5884 TURCO 6783 series ARDROX 6334 AL 333 SOLVEX ICE 113

Products authorized for use (replacement)

SINCLAIR S (SOCOMOR)

Pure methanol (AIR 3651)

Methanol/water 44/56 or 50/50

Minimum quality of water

Table 14: Cleaning Products

5.4.4.2 PROPORTION OF THE MIXTURE

For proper and effective washing, it is also imperative to have proper concentration of the washing product, based on the following table. It should be noted that for replacement products the percentages in cleaning mixture are different.

T0 Anti-freeze product (*) % v/v Cleaning product

% v/v Water % v/v

T0>5C (41F) 0 20 80

5C>T0>-8C (17.6F) 15 20 65

-8C> T0>-24C (11.2F) 30 20 50 Table 15: Proportion of Cleaning Mixture



The proportion of mixture for replacement products are listed as follows: For the replacement products :

o Cleaning product at 50% v/v: SOLVEX ICE 113 o Cleaning product at 25% v/v: AL 333 o Cleaning product at 20%v/v: Turco 6783-50 o Cleaning product at 10% v/v: ARDROX 6334, Turco 6783-3 o Cleaning product at 15% v/v: SINCLAIR S o Cleaning product at 5% v/v: TURCO 4217, TURCO 5884 o Ready to use cleaning product: Turco 6783-10.

Following points should be further noted in regards to proportion of the mixture: If the 44/56 or 50/50 methanol/water mixture is used, the proportions of

anti-freeze product must be doubled (*) Some products are RTU (Ready To Use) and do not require any water

(distilled or demineralised) (**) o This applies to ZOK 27 which also comes in a ready to use form:

ZOK 27 RTU, Ardrox 6368 and RMC-G21, o The proportions of the product are therefore

100% of the product for T0>5C, 15% anti-freeze + 85% product for 5C>T0>-8C and 30% anti-freeze + 70% product for -8C> T0>-24C.

5.5 FREQUENCY

Frequency of performing operations of Cleaning, Washing and Rinsing highly depend on the surroundings and operating conditions of the engine. Hence, it is advised that the operators based on performance decide the frequency of these operations. The frequencies suggested in the Maintenance Manual are the least required for given operating conditions; they should be increased based on environment, on-condition monitoring and performance deterioration:

5.5.1 GENERAL CASES

Operation Saline or corrosive atmosphere Polluted atmosphere

Rinsing Daily (after the last flight of the day) None

Washing Daily (after the last flight of the day) Daily

(after the last flight of the day) Cleaning See engine specifications (Makila aero: weekly, etc.)

See engine specifications (Makila aero: weekly, etc.)

Internal protection Before engine storage Before engine storage

External protection Before engine storage weekly Before engine storage

Table 16: Frequency of Cleaning Procedures in General Cases



5.5.2 SPECIFIC CASES

5.5.2.1 CLEANING

Drop in performance Before 72-hour downtime At the start of periodic inspections Before engine storage After ingestion of foreign bodies.

5.5.2.2 WASHING OR CLEANING (ACCORDING TO CONDITION OF THE ENGINE) After use of extinguishers on a hot engine After use of extinguishers on a cold engine

Apart form the frequencies mentioned above, specialized cleaning procedure can be suggested for performance recovery of the engines.

5.6 TOOLS

Tools play a major part in cleaning, as they Maintain the required flow speed. Maintain the amount of fluid flow Dictate the optimum droplet sizes of cleaning mixture Provide correct path for flow of cleaning mixture

Hence, for proper cleaning, it is mandatory that only Turbomeca approved tools at specified settings are used. Furthermore, the Tools (specifically Pressure Generator) should be checked and inspected regularly with specific equipment that whether they are providing required performance or not. The following table lists the Tools (with their respective part numbers) required for cleaning, washing and rinsing operations:

Arriel 2S2 Makila 2A Arrius 2B2

Pressure Generator Tank OT 20 0010 TM0188G002 OT 71 0050 8818480000

OT 0057 TM0188G001

Compressor Washing Unit N.A. Attached to Engine Attached to

Engine

Equipped Flow Limiter OT 20 0020 8819505000 N.A. N.A.

Bleed valve Blanking union

OT 20 0030 8816517000 N.A. N.A.

Table 17: List of Required Tools

Few tools are required for cleaning, washing and rinsing of engines which include:



Spray Equipment o Pressure Generator Tank o Nozzle o Below is the table of various parts that are present in a generic Pressure Generator

Tank (The Symbols correspond to the illustration provided in Figure X)

Figure 8: Pressure Generator Table 18: Pressure Generator, Arriel 2S2

Flow Limiter o To limit the flow rate of cleaning mixture from the pressure generator tank

Bleed Valve Blanking Union o To close the flap of bleed valve when connected to an external air supply

Compressor Washing Unit o Dictates the flow path of cleaning mixture o Usually has a quick connect option where nozzle pipe from pressure generator can

be connected, and cleaning can be carried out easily o Provides an optimum path for flow of the cleaning mixture

Figure 9: Compressor Washing Unit for Makila 2A



5.7 PRODUCTS USED

The products pertaining to each of the operations have been already listed with the respective processes. Here, we give an overview of the same.

The products used for Cleaning, Washing and Rinsing are divided into two categories: Validated products: products validated by the CVI that can be used in rinsing,

washing, cleaning and protection operations. Products authorized for use: products authorized by the CVI for use if the validated

products cannot be used.

The CVI is abbreviation for Consumable Validation Committee which validates and authorizes the chemical products which can be used for Cleaning, Washing and Rinsing. Without its approval, use of chemicals is not allowed.

While using the products, proper care must be taken to protect self and the engine. Also, the percentages of product should be correctly and properly added, doing otherwise might lead to negative effects. Some products, especially the Ready-to-Use products and Replacement products are required to be added in different percentages. The ambient temperature also influences the concentration of the products.

As various Chemical products are recommended and approved it is the choice of the operator to choose one from them. Though, Turbomeca makes no distinction between the recommended cleaning products following parameters can be used while choosing the most-suited product by a helicopter operator:

Cost o Of Purchasing o Of Disposal

Availability o Based on region

Effectiveness o Based on previous experience

Environmental Friendly Boiling Point

o Higher boiling point of product is advantageous for cleaning o Since, the engine temperature rises very rapidly once it is turned on it may

cause evaporation of the cleaning mixture o This can result in an incomplete or ineffective cleaning

While estimating the cost of cleaning product the cost of disposal should also be accounted for. If the cleaning product is environmental friendly the cost of disposal will be lesser, and hence it is advantageous to have the same. Also while choosing the cleaning products amount of surfactants and boiling point of the cleaning product is an important factor. It is better to have cleaning mixture with higher boiling point for proper cleaning. If the boiling point of cleaning mixture it shall evaporate very quickly once the engine is started and will not be able to cool aft stages of compressor and turbine.

Apart from chemicals the primary consumable required for engine cleaning is water. The quality of water is very important, and hence only recommended or approved water should be used. The Validated (recommended) water quality for use is that of:



Distilled Water o Appearance: clear, limpid, colourless, with no deposits or materials in

suspension o Conductivity at 25C : 5 S/cm maximum o pH: 5 7.5

Demineralised water o Appearance: clear, limpid, colourless, with no deposits or materials in

suspension. o Conductivity at 25C : 10 S/cm maximum. o pH: 5 7.5.

The Authorised (replacement) water quality for use is listed below. It should be used only in rare and exceptional circumstances. The characteristics required for replacement water are as follows:

Minimum Quality Water o Appearance: clear, limpid, colourless, with no deposits or materials in

suspension o Particles remaining after evaporation at 110C: ma ximum of 175 ppm o Chloride content: 15 ppm maximum o Sulphate content: 10 ppm maximum o Sodium content: 10 ppm maximum o Conductivity at 25C (optional): 400 S/cm maximum o pH: 6 8.5. o Hardness: 18F maximum

Note: 1F = 4 ppm of Ca 2+ = 2.4 ppm of Mg 2+ = 10 ppm of CaCO3

Irrespective of the supply source of this water, the above conditions must be guaranteed over time. The criteria specified for inspection of quality of water is based on ISO 3696 standards, and they should be referred in case of any confusion. The risk of contamination increases from distilled water to demineralised water and becomes significant if the minimum quality of water is used. Nevertheless, it remains acceptable if the water quality criteria are met.

If the water properties are sub-standard the water instead of cleaning can cause various deposits and contamination of the engine. Following problems can occur in case minimum water quality is not met:

Blocking of the combustion chamber, which obstructs the air accesses in the chamber and causes poor combustion,

Presence of deposits on the turbine blade, which become coked during use and cause a change in flow,

Corrosion of the turbines and compressors caused by too great a quantity of chloride, sulphate and alkaline ions in the liquid,

Corrosion of the compressors and the bearings by stagnant water if the drying is poorly carried out.

Finally, it should be duly noted that the tap or drinking water should not be used for Engine cleaning purposes. Drinking water is a definition that deals with food hygiene and is not same as the criteria required for rinsing, washing or cleaning operations. It may contain large quantities of minerals (chlorides, sulphates, sodium, etc.) that can corrode or lay deposits on the engine.



5.8 CAUTIONS - HEALTH, SAFETY, ENVIRONMENT

While doing any type of maintenance, let alone Cleaning, Washing and Rinsing proper care must be taken to product oneself as well as the engine. Due to the use of chemicals it is necessary that proper equipment is used and care taken while doing operations of engine cleaning. Following must be specially noted:

Health and safety of the Operators: Do not breathe in cleaning product vapours. Work in a well-ventilated area. Never let the cleaning or protection products come into contact with the skin. Protect the hands with synthetic rubber gloves and the face with a screen or goggles.

Cleaning and protection products can be toxic, refer to the safety data sheets for the products used and implement the necessary precautions (wearing PPE, suitable storage conditions, etc.). Consult the supplier for any problems with or questions about the products.

Care of the Engines Use only distilled or demineralised water Use the recommended cleaning products. Other cleaning products cannot be used

without the agreement of TURBOMECA. Likewise, use the recommended anti-freeze products. Other anti-freeze products cannot

be used without the agreement of TURBOMECA. The supply time of Starter generator should comply with limitations provided in Aircraft

Flight Manual For treatments carried out during ventilation, ensure that the temperature T4.5 is less than

or equal to 70C for Makila and Arrius, and 100C f or Arriel.

Notes for proper Cleaning Cleaning Mixture

The mixture should be properly homogenized before use Proper percentages of chemicals should be added based on ambient

temperature and data provided in Maintenance Manual While using Ready-to-Use products care should be taken of not to mix them

with water Air Path

All the valves which could be affected should be closed Aircraft manufactures valves should be blanked

As far as possible Cleaning should be done with Ventilation (Dry Crank) Standard practices provided in Maintenance Manuals should be followed Value of N1 should be monitored

Injection should be started only when N1 reaches above 10% Injection should be stopped when N1 reaches below 10% While engine running N1 should not drop by more than 10% Prevents accumulation of cleaning product and Ensures proper action of cleaning mixture



6 CLEANING, WASHING AND RINSING CUSTOMER STUDIES Maintenance of engines due to variety of reasons, at times, might not be as smooth as desired and both Customers and the Service Providers have to work together in order to find out the solution and eliminate the problem. The problems in maintenance might appear due to either discrepancies in the Maintenance procedures (ambiguities or errors in Maintenance Manuals) or due to negligence on the Customers side (usage of incorrect tools, unqualified material) or due to extraneous factors (such as environmental conditions). To maintain the quality of the Maintenance and Support and avoid such undesirable circumstances, various measures are adopted which include

Proper and timely Training of Customer and Maintenance Engineers On-site Field Representative from the OEM to monitor the maintenance and for

troubleshooting Interaction of Customers(Engine Users) and Engineers(Designers and Manufacturers) for

proper communication of requirements and problems through Symposiums Continuous validation and verification of all the maintenance documents, specifically those

related to 1st Line Maintenance Improvement and simplification of the maintenance procedures to the best extent possible

without compromising the primary goal of safe and accurate maintenance

In the past, there have been times where the procedures specified for Engine Cleaning have to be monitored, modified and tailored specific to the customer in order to eliminate problems associated with Engine Cleaning and for proper Performance Recovery. Some such studies are described in this section.

Figure 10: Evolution of Procedure through Troubleshooting

When, such problems arise the engine user reports the problem to the Support department through the respective Field Representative. First, an attempt to troubleshoot the problem on-site is made without affecting the operations of the customer by monitoring the procedure, tools and equipments. If this does not yield solutions, detailed studies are carried out by Field Representatives and Service Engineers which might require some engines to be grounded. Based on the finding of the studies, solutions are proposed which might be in the form of explanation and corrections of mistake in maintenance procedures which the customer might be unknowingly making OR specifying Customer tailored maintenance procedures usually due to the environmental conditions or the operating regime of the Customers fleet. The solutions proposed are monitored for sufficient period in order to ensure that the problem is solved.


ENR0090-D Ce document est la proprit de la socit Turbomeca. Il ne peut tre communiqu ou reproduit sans son autorisation Le texte original de ce cahier des charges, crit en franais, fera fo i en cas dinterprtat ion et/ou de lit ige entre les part ies. This document is the property of Turbomeca and may not be copied, used or communicated without Turbomecas authorization In case of misin

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