special report – military aviation fuel filtration technology

Military Aviation Fuel Filtration Technology

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

Published by Global Business Media

Safety in Aviation Through Filtration and Sensing Technology

Surabaya – An Isolated Incident?

The Cautionary Tale of Flight BA 777 from Beijing, China to London, Heathrow in January 2008

Fuel Contamination, Aircraft Safety and Filtration

Biomass Contamination in New Zealand

Hard Truths About Energy: the Paradigm Shift

Sponsored by

Hard Truths About Energy: Hard Truths About Energy: Hard Truths About Energy: Hard Truths About Energy:

Biomass Contamination in New ZealandBiomass Contamination in New ZealandBiomass Contamination in New Zealand

SPECIAL REPORT: MILITARY AVIATION FUEL FILTRATION TECHNOLOGY


Global Business Media Limited 62 The Street Ashtead Surrey KT21 1AT United Kingdom

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Business Development DirectorMarie-Anne Brooks

EditorMary Dub

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Contents

Foreword 2Mary Dub, Editor

Safety in Aviation Through Filtration and Sensing Technology 3Faudi Aviation GmbH

Who We AreOur StrengthsContamination of FuelWhat is Meant by Clean Dry Fuel?The Most Common ContaminantsHow Does Fuel Get Contaminated?Mode of OperationOperationSignal OutputCalibrationThe AFGUARD® is Certifi ed For Use in Hazardous Areas

Surabaya – An Isolated Incident? 7Faudi Aviation Sensor, GmbH

Pilots Safely Land Airbus After Engine FailureFAUDI Aviation GmbH is Proud to Announce the Launch of the New DPGUARD®

The Cautionary Tale of Flight BA 777 from Beijing, China to London, Heathrow in January 2008 9Don McBarnet, Staff Writer

Simultaneous Power Failure of Both Engines Within 8 secondsThe Reduction in Engine Power was Caused by Ice Crystals in the FuelThe Level of Water in PPM Were Standard But Still Too High Causing Ice Crystals Blocking Fuel FlowThe Safety RecommendationsThe Role of Filtration of Water in Fuel of High Importance

Fuel Contamination, Aircraft Safety and Filtration 11Marushka Dubova, Defence Correspondent

The Nature of the SludgeThe Conundrum of Anti-Icing Additives

Biomass Contamination in New Zealand 13Meredith Llewellyn, Lead Contributor

The Fuel Filter Bypass by Black Sludge/Film

Hard Truths About Energy: the Paradigm Shift 14Don McBarnet, Staff Writer

SASOL Green FuelsHoneywell and ‘Syngas’

References 15

WWW.DEFENCEINDUSTRYREPORTS.COM | 1

Military Aviation Fuel Filtration Technology

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


Safety in Aviation Through Filtration and Sensing Technology

Surabaya – An Isolated Incident?

The Cautionary Tale of Flight BA 777 from Beijing, China to London, Heathrow in January 2008

Fuel Contamination, Aircraft Safety and Filtration

Biomass Contamination in New Zealand

Hard Truths About Energy: the Paradigm Shift

Sponsored by

Hard Truths About Energy: Hard Truths About Energy: Hard Truths About Energy: Hard Truths About Energy:

Biomass Contamination in New ZealandBiomass Contamination in New ZealandBiomass Contamination in New Zealand

Foreword

Fuel fi ltration systems for military and civilian

purposes are a fast changing and high

technology fi eld. The opening piece of this Special

Report traces the background and technology

of an organisation specialising in every type of

fi ltration and separation problem encountered in

the refuelling of both civil and military aircraft. It

goes on to describe the meaning of clean dry fuel,

examines some of the contaminants and looks at

a sensing measurement system which monitors

the quality of jet fuels, and gives an insight into its

mode of operation. This system has gone into full

production and is being used extensively by fuel

handling plants.

The second part of the Report describes the engine failure of an Airbus fl ying from Surabaya in Indonesia, which was forced to make an emergency landing at Hong Kong International Airport, and asks – How can this happen? It postulates that, had the refuelling vehicles and dispensers been equipped with an effective sensor system, this near-disaster could have been avoided.

In the third piece, the AAIB (Air Accident Investigation Board) report on the crash landing at Heathrow of BA 777 from Beijing in January 2008 is examined. This illustrates what an important issue this field is for aircraft security. According to the AAIB, the precipitating factor for the crash landing was ice crystals in the fuel causing reduced fuel fl ow to the engine.

As the fourth piece of this Report shows, the filtration of civilian and military aviation fuel is a

complex business. For example, the removal of soluble water and the addition of surfactants and additives to prevent freezing can catch fuel engineers in a double bind. The additives and fi lters to remove contaminants and prevent sludge and gels forming can themselves form sludges that contaminate the fuel.

Filtration systems do not just have to cope with water and chemicals. There are other substances that can change the lubricity of fuel. Organic compounds and biomass can create similar sudden and apparently unexplained changes in military and civilian aviation fuel. The fi fth article uses an illustration on this from the Civil Aviation Authority in New Zealand.

But what of the future? This is looked at in the fi nal piece. With United States defense forces one of the highest users of petroleum products, sustainable energy sources, that is security of supply and stable market prices, are the new paradigm for the Department of Defense. With research backing from DARPA (the Defense Advanced Research Projects Agency) and independent research from oil companies, new aviation fuel products are entering the market with the hope that they will be more environmentally friendly and less polluting. Whether oil companies will succeed in achieving their goal in reducing the consumption of petroleum products and delivering high quality uncontaminated military and civilian aviation fuels is an issue that we will all watch with interest.

Mary DubEditor


2 | WWW.DEFENCEINDUSTRYREPORTS.COM

Mary Dub has covered the defence fi eld in the United States and the UK as a television broadcaster, journalist and conference manager. Focused by a Masters in War Studies from King’s College, London, she annotates and highlights the interplay of armies, governments and industry.

this field is for aircraft security. According to the AAIB, the precipitating factor for the crash landing was ice crystals in the fuel causing reduced fuel fl ow to the engine.

As the fourth piece of this Report shows, the filtration of civilian and military aviation fuel is a

and civilian aviation fuels is an issue that we will all watch with interest.

Mary DubEditor

Mary Dub has covered the defence fi eld in the United States and the UK as a television broadcaster, journalist and conference manager. Focused by a Masters in War Studies from King’s College, London, she annotates and highlights the interplay of armies, governments and industry.

of soluble water and the addition of surfactants and additives to prevent freezing can catch fuel engineers in a double bind. The additives and fi lters to remove contaminants and prevent sludge and gels forming can themselves form sludges that contaminate the fuel.

Filtration systems do not just have to cope with water and chemicals. There are other substances that can change the lubricity of fuel. Organic compounds and biomass can create similar sudden and apparently unexplained changes in military and civilian aviation fuel. The fi fth article uses an illustration on this from the Civil Aviation Authority in New Zealand.

But what of the future? This is looked at in the fi nal piece. With United States defense forces one of the highest users of petroleum products, sustainable energy sources, that is security of supply and stable market prices, are the new paradigm for the Department of Defense. With research backing from DARPA (the Defense Advanced Research Projects Agency) and independent research from oil companies, new aviation fuel products are entering the market with the hope that they will be more environmentally friendly and less polluting. Whether oil companies will succeed in achieving their goal in reducing the consumption of petroleum products



Safety in Aviation Through Filtration and Sensing TechnologyFaudi Aviation GmbH

PERHAPS IT is a little known fact that aircraft safety depends largely on the cleanliness

of fuel, with contaminated aviation fuel being one of the main causes of critical situations. In view of this, an ever-growing number of oil companies who refuel both civil and military aircraft have come to rely on the advanced aviation fuel fi ltration systems and components offered by FAUDI Aviation GmbH. The long established German enterprise and its product solutions meet all national and international standards, including the latest editions of API, EI and military standards.

The FAUDI Aviation motto “quality guarantees safety” is imbued in the everyday culture of this small to medium-sized company. The aim of FAUDI Aviation is to contribute to the end-users security. FAUDI Aviation wants them to feel save during the entire process chain until the fuel reached the aircraft. Clean and dry Aviation Fuel makes for safe fl ying.

The FAUDI Company was founded in 1938 by Fritz Faudi and has been continuously involved in the fi ltration and separation of aviation fuels, industrial liquids and gases. FAUDI deserves his world-wide customer-base and is well known in the fi eld of aviation fuel fi ltration. With over 70

years’ experience and having state-of-the-art facilities, FAUDI Aviation offers highly effi cient and cost effective solutions for a range of fi ltration and separation problems.

In order to fi nd a remedy to those problems, FAUDI rely on an extremely motivated and highly experienced workforce of engineers, technicians and designers who enable the Company to carry out projects meeting all customer requirements and standards both national and international.

Who We AreWith a workforce of 50 people, FAUDI Aviation is in a position to assist with whatever fi ltration or separation problems customers may require. FAUDI Aviation also benefi ts from having one of the largest, most modern civil Aviation Fuel Test Rigs in Europe enabling continued product development and dynamic testing under controlled conditions of filter elements and systems.

Our Strengths- Customer-orientation- Quality dedicated - Delivery in time- Specifi cation know-how



The transport of fuel

from the refi nery to the

aircraft offers many

opportunities for various

types of contaminants to

enter the fuel system.

(EI Approvals, Military Approvals etc.)- Total quality management (TQM) - Service orientation- Competitive prices- Trainings and Seminars

Contamination of FuelThe safety of aircraft depends upon the cleanliness of its fuel. Uncontaminated aviation fuel is taken for granted. Blocked fuel lines are virtually unknown and have rarely been blamed for crashes.

What is Meant by Clean Dry Fuel?1. Fuel free from particle and water contamination2. Fuel having a clean and bright appearance

The Most Common Contaminants1. Water (dissolved water, free water)2. Solids (rust, dirt)3. Microorganisms4. Surfactants

How Does Fuel Get Contaminated?The transport of fuel from the refinery to the aircraft offers many opportunities for various types of contaminants to enter the fuel system. Tank trucks, barges, tank wagons and pipelines are the most common means of transporting fuel from the refi nery to the terminal storage facilities. Finally, the aircraft is fuelled by a refueller truck from airport storage or by hydrant cart from a hydrant system. Each time the fuel is transported or stored, contamination may occur even if precautionary measures have been taken. The removal of dirt and water from jet fuel supply is a continuous battle up to the point where fuel

is burnt in the aircraft engine / turbine. FAUDI Aviation high quality fi lters are fi ghting a primary defence against dirt and water contamination. “Prevention is better than cure.” There are fi lter water separators, microfi lters, at every transfer point from the refi nery to the aircraft. This fi ltering process ensures that fuel is free from dirt and undissolved water which could freeze and block the supply system. It also protects parts from dirt, corrosion and the growth of micro-organisms.

Because water absorbent polymer from monitor elements may migrate downstream, they are no longer allowed for use in military applications and were reduced to 1 year use for civil applications conforming to JIG bulletins in 2006. Knowing that Monitor vessels are available, Faudi propose to all military customers a replacement, free-of-charge, of 2” monitors by 2” microfi lters. The guaranteed lifetime of these fi lters increase to three years, due to the control function of the AFGUARD®, which is a new sensing device.

Continuous measurement of free water in jet fuel during the whole process, from the refi nery to the aircraft, is needed. Sensing technology allows control of the whole process in terms of free water content. As mentioned above, monitors (water absorbing cartridges) are no longer used for military applications, denying the last opportunity to preserve the aircraft from free water. Until now, sample controls have been carried out at the beginning. Technology now enables monitoring of the whole refuelling process and to introduce relevant accessories where free water becomes evident.

The FAUDI Aviation AFGUARD® is a sensing measurement system which monitors the quality of jet fuels. The AFGUARD® is an in-situ sensor able to detect the content of free water in jet fuel. The principle of measuring can be described as refraction index bases IR scattered light effect.

Mode of OperationA precisely defined, constant IR-light beam penetrates the process medium. Scattered light from particles (undissolved liquids like free water or gas bubbles) in the medium is detected by photo diodes. It is also possible to determine a water slug in jet fuel.

The AFGUARD® can be used perfectly to detect the functionality of Filter Water Separators or to

1 2

3 4



measure the water absorbing performance of Filter Monitors. This can be done by measuring the level of free water detected by AFGUARD® sensors, placed at the vessel inlet and outlet. Free water will be detected and, with AFGUARD® in place, the monitors are under constant surveillance to ensure their proper function. This could result in extended service life for FAUDI Aviation Elements, provided that the indicated differential pressure range is respected.

The AFGUARD® permits either a complete monitoring or just control of water concentration limits along the refuelling process. Normally, the customer would switch the AFGUARD® with the on-board computer of the refuelling truck or with every interface capable of reading a linear analogue output signal from 4 to 20 mA.

The AFGUARD® can be added to by several types of accessories such as dry-break-coupling, intrinsically safe barriers, on-site displays, data loggers etc.

OperationClean FuelPulsed IR light – (Transmitter A) leaves the optics under defi ned refraction index, passing through the jet fuel until the mirror is reached, then refl ected back to the optics where the signal intensity is being measured. The difference between transmitted and received light intensity will be handled for internal adjustment, for example, if there is some debris on the optics or the mirror caused by dirt in the jet fuel.Self check of electronicsSo long as there is not a drop of free water in the measuring zone, there will be no scattered light.

Fuel with Free WaterFree water in jet fuel as fi ne dispersed second phase will be detected as scattered light by receiver C. During the whole process the self checking functionality of the electronics is ongoing.

Only Water (Water Slug)If there is a pure water phase, the refraction index will change. This results in another angle of light beam leaving the optics (A). Under this principle it is easy to differentiate between jet fuel and water.

Signal OutputThe signal output of the AFGUARD® is 4 to 20 mA as a worldwide standard.

The AFGUARD®

permits either a

complete monitoring

or just control of water

concentration limits along

the refuelling process.

Clean fuel Fuel with free water Only water

A: lightsourceB: refl ected signal

A: lightsourceC: scattered signal

A: lightsource



The AFGUARD® is

destined to become

the sensor technology

that will replace other

means of chemical

detection in the future,

because it works with

much more accuracy and

is the most cost effective

in its applications.

In addition, the AFGUARD® gives out a lower and upper signal.

Signal Output < 3.5 mA Self Check – Fail Safe (Electronics)4 to 20 mA Measuring range 0 to 50 ppm or 0 to 100 ppm> 20.5 mA Water slug, Gas phases, AVGAS

CalibrationEvery sensing device needs to be calibrated prior to use. Therefore the AFGUARD® leaves the factory pre calibrated (commonly to Jet A1). The 4 to 20 mA signal output relates to the calibrated measurement range and is strictly linear. FAUDI Aviation recommends a recalibration on a yearly basis. To optimize the accuracy of measurement FAUDI has developed a calibration set for on-site calibration.

The AFGUARD® is Certifi ed For Use in Hazardous AreasStadtallendorf, August 2009.After undergoing test and development phases, the AFGUARD® has gone into full production and is being implemented at large fuel handling plants. We know that it will show successfully what the future of aviation fuelling needs. Topping off our research is the fact that we received the hazardous area certifi cation for zone 0/1 and zone 2, qualifying it for use in all hazardous areas world wide. This most important certifi cation shows that AFGUARD® fulfi ls the requirements according to the EI Model Code of Safe Practice Part 15 (EI 15) as specifi ed by the Energy Institute.

This area code covers installations handling flammable fluids and is a well-established, internationally accepted publication that provides methodologies for hazardous area classifi cation around equipment storing or handling fl ammable fl uids in the production, distribution and retail

sectors and should be applied by process safety practitioners involved in hazardous area classifi cation.

The AFGUARD® is destined to become the sensor technology that will replace other means of chemical detection in the future, because it works with much more accuracy and is the most cost effective in its applications.

As mentioned above, the FAUDI AFGUARD® is the perfect device to get visibility of water content in jet fuel along the whole process of refuelling. It is the only sensing tool being manufactured and approved for use in EX areas. Therefore with the AFGUARD®, FAUDI Aviation contributes to more safety in the aviation business for every customer.

More information on FAUDI Aviation can be found on the internet at www.faudi-aviation.com.

Contact details:FAUDI Aviation Sensor GmbHAttn. Mr. Matthias AdenPhone: +49 (0) 6428 4465 – 212Fax: +49 (0) 6428 4465 – 221E-Mail: [email protected]



Surabaya – An Isolated Incident?Faudi Aviation GmbH

FORTUNATELY, NO victims were reported on this incident as the crew were able to

make a successful emergency landing at Hong Kong airport. Nevertheless, some people were injured when they left the aircraft on the emergency evacuating. The investigation revealed that on the refuelling at Surabaya airport, a monitor element had collapsed unnoticed and thus, Super Absorbent Material was released into the fuel system of the Airbus. This contamination affected both engines so that the thrust decreased to 74% of engine no. 1 and 17% of engine no. 2.To see the complete investigation report use following link in your browser:http://www.unpl.eu/upload/pdf/A330%20Cathay%20Accident%20Bulletin%201%202011.pdf

For us, as manufacturer of fi lter systems for aircraft refuelling, we ask ourselves the question – How could this happen? Usually, refuelling vehicles and dispensers are not equipped with

a sensor system which is able to recognise such cases. Thus, no automatic interruption of the refuelling procedure can take place. Our experience shows that often the refuelling crew do not have the necessary knowledge. In addition, low payments and often a high fluctuation do not increase the motivation of the staff in many countries. It is clear to us that these circumstances can be changed, but not immediately. It remains for us to use automatic systems which immediately interrupt the refuelling procedure in an emergency. In this case, the flow rate was much less than the maximum possible fl ow rate of the monitor vessel during refuelling. A well known piston differential pressure gauge between entrance and exit of the vessel does not indicate the actual differential pressure related to the actual fl ow rate. Therefore an immediate rise of the (real) differential pressure cannot be noticed by the service people. As mentioned in the investigation report:

Pilots Safely Land Airbus After Engine Failure

Two pilots saved the lives of more than 300 passengers by safely landing an Airbus after experiencing engine failure upon its descent to Hong Kong.

Eight people were injured after Cathay Pacifi c fl ight CX780 from Surabaya in Indonesia made its emergency landing at Hong Kong International Airport.

The two pilots, both Australian, lost the use of the left hand engine shortly after the Cathay Pacifi c fl ight CX780 from Indonesia reached cruising altitude after taking off for the four hour 40 minute fl ight.

As an Airbus is able to fl y and land safely on one engine provided if in range of an alternative airport, it continued towards Hong Kong with 322 passengers and crew.

However upon descent, the second engine repeatedly cut out, meaning the plane effectively glided at high speed towards the airport as the pilots struggled to keep it on course. As the plane was making its fi nal approach over the sea, they managed to get enough thrust in the right hand engine to carry it safely to the runway.

Landing at a high speed, the pilots then managed to employ reverse thrust as well as other braking devices to bring the plane to a stop, setting the tyres on fi re as they did so but bringing the aircraft to a safe standstill. Eight people were injured during the incident, but the majority were caused by people hurting themselves as they jumped down the emergency slides to the ground.

“It was an amazing piece of piloting in extremely testing circumstances,” a pilot colleague said. “One engine was shut down completely and the other was going on and off. They effectively landed the plane on half an engine.”

13 Apr 2010 by Simon Parry in Hong Kong for “The Telegraph“ (Text shortened)



“The recording and monitoring of the weekly differential pressure of the dispensers was not performed properly. The differential pressure reading, which was taken under low fl ow rates during refuelling operation, may not have correctly indicated the condition of the fi lter monitors“. In such cases the monitor elements can quickly reach their maximum capacity and block. Thus the real differential pressure cannot be seen on the piston differential pressure gauge. For this reason, a collapsing of the elements, due to exceeding the defi ned bursting pressure is quite possible. In order to prevent such cases in the future, FAUDI Aviation developed a control unit named DPGUARD® which is able to monitor the real differential pressure, depending on the actual fl ow rate, and to switch-off the refuelling if necessary.

FAUDI Aviation GmbH is Proud to Announce the Launch of the New DPGUARD®

The DPGUARD® has been designed to give out corrected differential pressure values for all types of filter used in aviation refuelling, bringing more safety aspects into refuelling operations worldwide.

The DPGUARD® is a self-learning system, consisting of a fully automated touch screen operated minicomputer, integrated in a hard disk IP 65 Box (for wall mounting). It catches electronic signals from differential pressure sensors and related electronic fl ow signals to mathematically correct and calculate the related differential pressure functionality and give out corrected differential pressure values related to maximal / rated fl ow. There is no need to preconfi gure special types of elements such as Monitors, Coalescers, Micro fi lters, Clay – canisters etc.

It fully automatically detects the differential pressure behaviour of the elements in use and gives out the most exact corrected differential pressure curve ever – closest to reality without testing at test rig.

The differential pressure curve is always related to the actual differential pressure behaviour of the elements in use. The mathematical functionality is independent of manufacturer or type of element. There is no need for calibration or adjustment for special types of fi lter element – this is applied by the fully automated detection algorithm behind the DPGUARD®.

The DPGUARD® only needs to be confi gured to handle incoming signals from differential pressure sensors across the elements and related flow signals. In addition, the user is asked to adjust warning and alarm levels to be informed if corrected differential pressure values are going to exceed predefi ned levels.

The investigation revealed

that on the refuelling

at Surabaya airport, a

monitor element had

collapsed unnoticed and

thus, Super Absorbent

Material was released

into the fuel system

of the Airbus.



These warnings or alarms can be used to address digital output or relays to automatically initiate relevant actions.

Due to the functionality of in -built data logger, the DPGUARD® is able to identify pressure increase or losses in differential pressure across the filter elements (e.g. pressure loss caused by ruptured filter elements) to automatically address digital output or relays to stop the fuelling process instantly without necessary human intervention. All stored real and calculated differential pressure values together with status (ready, warning, alarm level) gives the highest level of documentation ever.

In addition to DPGUARD®´s main function to calculate corrected differential pressure values, the DPGUARD® can also be used to remind about time or throughput-related end criteria of fi lter elements. This could be helpful if lifetime related filter exchange should be carried out e.g. for Monitor fi lters (1 year lifetime). It also fulfils the ATA 103 requirement of recorded throughput of elements at the time of inspection or change out.

For an instant overview of filter behaviour, the DPGUARD® provides the stored corrected differential pressure curve as a graph to display visually the behaviour of installed fi lter elements.

DPGUARD® has a very wide range of connectivity to be integrated in every known system via current (0 /4 … 20 mA), voltage (0 to 10 V), LAN, WLAN, Ethernet, CAN-BUS or other types of bus systems.

Ingress protection is IP 65 to be installed in safe area locations.

The DPGUARD® has

been designed to give

out corrected differential

pressure values for

all types of fi lter used

in aviation refuelling,

bringing more safety

aspects into refuelling

operations worldwide.



The Cautionary Tale of Flight BA 777 from Beijing, China to London, Heathrow in January 2008Don McBarnet, Staff Writer

Simultaneous Power Failure of Both Engines Within 8 secondsThe Air Accident Investigation Report describes what happened:“Whilst on approach to London (Heathrow) from Beijing, China, at 720 feet agl, the right engine of G-YMMM ceased responding to auto throttle commands for increased power and instead the power reduced to 1.03 Engine Pressure Ratio (EPR). Seven seconds later the left engine power reduced to 1.02 EPR. This reduction led to a loss of airspeed and the aircraft touching down some 330 m short of the paved surface of Runway 27L at London Heathrow. The investigation identifi ed that the reduction in thrust was due to restricted fuel fl ow to both engines.”1

The Reduction in Engine Power was Caused by Ice Crystals in the FuelThe ice crystals in the fuel impeded the fl ow of fuel in both engines such that they were unable to deliver the thrust required to maintain fl ight speed.

“9. At 720 ft agl the right engine suffered an uncommanded reduction in engine power to 1.03 EPR and seven seconds later the left engine suffered an uncommanded reduction in engine power to 1.02 EPR.

10. The right engine fuel fl ow reduced to 6,000 pph and the left engine fuel fl ow reduced to 5,000 pph, levels above those required by an engine at fl ight idle.”2 After extensive investigations, the Air Accident Investigation Board reported on what they saw as the probable causes of the crash:“The investigation identified the following probable causal factors that led to the fuel fl ow restrictions:1) Accreted ice from within the fuel system released, causing a restriction to the engine fuel fl ow at the face of the Fuel Oil Heat Exchanger (FOHE), on both of the engines.2) Ice had formed within the fuel system, from water that occurred naturally in the fuel, whilst the aircraft operated with low fuel fl ows over a long period and the localised fuel temperatures were in an area described as the ‘sticky range’ (around -12 degrees C)3) The FOHE, although compliant with the applicable certifi cation requirements, was shown to be susceptible to restriction when presented with soft ice in a high concentration, with a fuel temperature that is below 10°C and a fuel fl ow above fl ight idle.4) Certification requirements, with which the aircraft and engine fuel systems had to comply, did not take account of this phenomenon as the risk was unrecognised at that time.”3

“As the fi nal approach started I became aware that there was no power… Suddenly, there was nothing from any of the engines, and the plane started to glide.”

John Coward, the Senior First Offi cer who was piloting the plane at the time of the incident.

The incident happened on January 17 2008 when John Coward, the Senior First Offi cer, brought the Boeing jet carrying 136 passengers from Beijing into a crash landing short of the Heathrow runway at 12.42 on that wintry January day injuring 47 people.

If anyone was to doubt the importance of fuel fi ltration systems for aircraft safety, they should read the Air Accident Board’s report on the causes of the incident at Heathrow.

Daily Mirror

If anyone was to doubt the

importance of fuel fi ltration

systems for aircraft safety,

they should read the Air

Accident Board’s report

on the causes of the

incident at Heathrow.



The Level of Water in PPM Were Standard But Still Too High Causing Ice Crystals Blocking Fuel FlowThe highly detailed report notes that the type of fuel used on the 5,000 mi fl ight met the detailed specifi cations of the engine manufacturers:“65. The fuel onboard G-YMMM was consistent with Jet A-1 and met the Defence Standard 91-91 and ASTM D1655.66. The fuel sampled from G-YMMM contained 35 to 40 ppm of water, which was similar to that found on other aircraft that had fl own similar routes.67. The fuel had not, at any time during the fl ight, cooled to a temperature at which it would suffer from fuel waxing.”4

So what had gone wrong to cause the power failure so unexpectedly in both of the two engines at about the same time? Jet A1 fuel to be used in winter has high specifi cations. According to ExxonMobil Jet A-1 must have a freeze point of -47 ºC or below5. Only Jet B for fl ying in winter over Canada or military aviation fuel has higher specifi cations. It will have been checked and fi ltered several times on refueling and within the plane on fl ight; however, on this occasion an unforeseen event of crystal formation in the FOHE occurred unexpectedly. The fi ltration systems and the fuel management system were not adequate for the demands made on them during this fl ight from China. The AAIB board investigations resulted in new safety recommendations by the Board. The outcome of the fl ight and the AAIB recommendations were so serious that airplane and engine manufacturers instigated further immediate research on the behavior of water in Jet A1 fuel during fl ight.

The Safety RecommendationsAs a result of the incident, the AAIB issued a number of recommendations. Boeing and the manufacturers of the Trent 800 engines were asked to introduce “interim measures”, “to reduce the risk of ice formed from water in aviation turbine fuel causing a restriction in the fuel feed system.”6 The Federal Aviation Administration and the European Aviation Safety Agency were asked to review certifi cation requirements so that “aircraft and engine fuel systems are tolerant to the potential build up and sudden release of ice in the fuel feed systems.” The same two bodies were asked to mandate design changes on Boeing and the engine manufacturers “to prevent ice from causing a restriction to the fuel fl ow at the fuel oil heat exchanger”. The further use of anti-ice additives in aviation turbine fuel on civil aircraft were to be considered and, most importantly, given the unexpected and unknown behavior of the ice crystals in the fuel, further joint research was called for.

“Research is also required to establish how ice accumulates in a fuel system and to establish the factors that may cause it to be released in a suffi cient concentration to restrict the fuel flow. The results of this research can then be used to further develop the industry guidance on fuel system design, materials, and the development of test procedures for aircraft fuel systems.”7

The Role of Filtration of Water in Fuel of High ImportanceSo three years after this incident, where luckily no one was killed, the reduction and monitoring of water in aviation fuel for both civilian and military use is at the top of the safety and research agenda and is being actively reviewed and followed up by international bodies. The daily routine fi ltration and monitoring of civil and military aviation fuel had become an exercise of high importance.

The reduction and

monitoring of water in

aviation fuel for both

civilian and military use is

at the top of the safety and

research agenda.



Fuel Contamination, Aircraft Safety and FiltrationMarushka Dubova, Defence Correspondent

THE SPECIFICATIONS for civil and military aviation fuel are stringent and

monitored by frequent checks by suppliers and users on transfer, fuelling and during use. Military aviation fuels tend to be of a higher specification than civilian fuels because of their use in more extreme circumstances for combat and sustained activities outside routine hub to hub fl ights. According to Shell, JP-4, the military equivalent of Jet B (with the addition of corrosion inhibitor and anti-icing additives) is rarely used now. It has been replaced by JP-8, which is the military equivalent of Jet A-1 with the addition of corrosion inhibitor and anti-icing additives; it meets the requirements of the U.S. Military Specifi cation MIL-T-83188D. (The UK also have a specifi cation for this grade namely DEF STAN 91-87 AVTUR/FSII (formerly DERD 2453). NATO Code F-34. JP-5 is a high fl ash point kerosene for use in aircraft carriers (the UK Military specifi cation for this grade is DEF STAN 91-86 AVCAT/FSII formerly DERD 2452).

As was demonstrated by the incident with BA 777, anti-icing additives are potentially of high value to aviation fuel. But the anti-icing additives have their own associated risks as the military research conducted for the Department of Defense on the incidence of contamination by “an apple jelly like substance” reveals. These sludge or “apple jelly” like formations in the fuel in the airplane fuel tank or in storage can increase maintenance costs and impede fuel fl ow. In a report for the Defense Energy Support Center (DESC) J. Andrew Waynick and Steven R. Westbrook reported on their extensive research work on the issue on the nature of this “apple jelly” type substance or “contaminated water bottoms”8 that was found in fuel storage tanks and onboard fuel tanks in military aircraft.

The Nature of the Sludge“This work has demonstrated that apple jelly is a complex mixture. It begins with water and DiEGME (diethylene glycol mono-methyl ether). This mixture reacts with its environment, extracting and dissolving compounds from the materials with which it comes in contact.” DIEGME is a Fuel System Ice Inhibitor (FSII) additive used in military aircraft fuel. It is added to JP-8 and JP-5 jet fuels at concentrations of 0.1% to 0.15%9. However, DIEGME separates from the jet fuel and collects in concentrations high enough to cause FTTP (fuel tank topcoat peeling). Such coating failures have lead to additional cost, requiring unscheduled maintenance, decreased safety, and decreased mission readiness and overall capability.10

So civil and military fuel engineers have to balance the gains of using FSII to inhibit ice crystal formation with the risk of “apple jelly” or “contaminated water bottom” sludge slowing down fuel flow to engines in flight. Worse for fi ltration specialists, the defense fuel researchers found the presence of sodium in the apple jelly. This sodium an additional contaminant may have originated from the fuel fi ltration systems used to reduce the presence of contaminants, the ultimate Catch-22.

“We know that the majority of the sodium comes from the water-adsorbing fi lters. They are the only source suffi ciently concentrated in sodium to provide the sodium levels observed in apple jelly, especially the thick apple jelly. The relative amounts contributed by any other source are impossible to ascertain. Still, some conclusions are possible. As an example, thin apple jelly tends to be lower in sodium. This probably means it has had less exposure to water-adsorbing fi lters. Hence, it also has little or no thickener so its viscosity is low.”

IATA: Jointly Operated Systems

“Fuel should be clear, bright and visually free from solid matter and

undissolved water at ambient temperature. For guidance on contamination

limits for into-plane fuelling, refer to IATA Guidance Material for Aviation

Turbine Fuels Specifi cations, 5th Edition, January 2004 (Part III).”

So civil and military fuel

engineers have to balance

the gains of using FSII to

inhibit ice crystal formation

with the risk of “apple

jelly” or “contaminated

water bottom” sludge

slowing down fuel fl ow to

engines in fl ight.



The Conundrum of Anti-Icing AdditivesTheir research throws up a list of related problems, which reveal how important fuel filtration is. They detail the complexity of the issue:

“The only effective way to eliminate this problem contaminant (whether you call it apple jelly or contaminated water bottoms) is to eliminate either the DiEGME, or the water, or both. In fact, simply eliminating the water may not solve all problems since the DiEGME remains a potentially damaging compound if it is not properly mixed into the fuel.”

The other conundrum that their research indicates is the higher level of prevalence of the apple jelly in the United States than in Europe or Pacific regions. This, their field research indicates, is because of different forms of storage and treatment of military aviation fuels in Europe, which favour lower levels of water and DiEGME.For example:“� In Europe, JP-8 is additive immediately prior to

shipment to the bases so there is less chance of water/DiEGME mixtures forming.

� In Europe, JP-8 is stored in fi xed-roof, cut-and-cover tanks, which reduces the amount of water in the fuel system.

� NATO tank design provides more effective removal of water/FSII from tank sumps.”11

The other conundrum

that their research

indicates is the higher

level of prevalence of the

apple jelly in the United

States than in Europe

or Pacifi c regions.



Biomass Contamination in New ZealandMeredith Llewellyn, Lead Contributor

MEETING THE standards set by IATA and Defence Standard 91-91 are a continuing

challenge. The biomass incident reported by the Civil Aviation Authority in New Zealand in 2004 is a good illustration of the challenge to fi ltration systems from the presence of biomass sludge. This illustrates how the presence of any water at all in fuel can lead to serious problems.

“In February 2004, the CAA received notifi cation that some aircraft were experiencing fuel fi lter bypass indications on medium-large transport aircraft using Jet A1 fuel. Subsequent inspections found that the fi lters contained a black sludge/film. Inspection of other aircraft found similar results to varying degrees... consequently, a NOTAM was issued on 23 February 2004 advising aircraft operators to monitor Jet A-1 aircraft fuel fi lters with extra vigilance.”

The Fuel Filter Bypass by Black Sludge/FilmAccording to the CAA website, when the sludge starts to block the filter, differential pressure increases, potentially exceeding a preset limit. A warning is given that the fi lter is becoming blocked. At a preset level the sludge will bypass the fi lter so that fuel can still be supplied to the engine. Research indicated that the sludge was organic in nature and was there because of the presence of soluble or other water in the fuel. Research revealed that the sludge was complex:

“Initial indications are that the black material in the fi lters was largely inorganic in nature and consisted primarily of the elements sulphur, iron, sodium, and calcium. Analysis of the fuel tank samples indicated that the microbiological (fungi and bacteria) contamination was very slight. One sample showed a ‘very heavy’

concentration of yeast. A further fuel tank sample was independently tested and found to contain copper, sodium and iron.”12

Biocides are periodically permitted to deal with the biomass problem under military regulations.

“Biocides are permitted by engine and airframe manufacturers for intermittent use during maintenance turnaround. The aircraft are refilled and fully dosed and, as a general rule, will fly on the treated fuel until it is fully used up. Fuel System Icing Inhibitor may also serve to inhibit fungal and bacterial growth in aircraft fuel systems, but may not do so reliably. As an example, it is known that fuels containing FSII, which have not been stored or handled properly, are susceptible to microbiological contamination.”13

“F.1 The visual appearance of the product is a good indication of contamination

and remains a key requirement for fuel throughout the distribution system. However,

interpretation of the appearance requirement can lead to problems due to the subjective

nature of the visual assessment. Therefore, a quantitative limit has been established

for particulate contamination. A maximum particulate contamination of 1.0 mg/l, when

tested to IP 423/ ASTM D 5452, shall apply at point of manufacture only.

F.2 Fuels containing visual particulate or with particulate levels greater than 1.0 mg/l will

require additional handling procedures, such as extended settling and/or fi ltration.”

DEFENCE STANDARD 91-91 ISSUE 5

The biomass incident

reported by the Civil

Aviation Authority in

New Zealand in 2004

is a good illustration

of the challenge to

fi ltration systems

from the presence of

biomass sludge.



Hard Truths About Energy: the Paradigm ShiftDon McBarnet, Staff Writer

IN 2007 the National Petroleum Council published a report on American energy

policy. It was a wide ranging and trenchant review which, according to the executive summary, “provides insights on energy market dynamics as well as advice on an integrated set of actions needed immediately to ensure adequate and reliable supplies of energy, while assuring continued expansion of prosperity including economic growth, global securi t y, and environmental responsibility”.14 The Department of Defense walked up to the plate and took the challenge as the largest single user of petroleum products in the world. The Defense Advanced Research Projects Agency (DARPA) is working on Vulcan, a program to design, build and demonstrate a full-scale constant volume combustion (CVC) power generation turbine engine. CVC technologies have the potential to signifi cantly decrease the fuel consumption of gas turbine engines.

SASOL Green FuelsHowever, in parallel to attempts to improve the fuel effi ciency of engines, infl uential work has been done to develop other sources of fuel. Sasol of South Africa is nearing approval of a 100% synthetic jet fuel. It is still going through the process of approval by QinetiQ for the Aviation Fuels Committee (AFC), a joint civil/military body that advises the UK Ministry of Defense on aviation fuel and development of the specifi cation.15

Honeywell and ‘Syngas’Honeywell, according to its web site, has demonstrated success with its renewable jet fuels:

“Originally developed under a U.S. Defense Advanced Research Projects Agency (DARPA) contract, UOP’s Renewable Jet Fuel process produces high-quali ty, renewable jet fuel that performs just like petroleum fuels. Made from non-food, second-generation feedstock like camelina, jatropha and algae, Honeywell Green Jet Fuel meets or exceeds all critical specifi cations for fl ight. At a 50-percent blend, it can be a drop-in replacement, requiring no changes to fleet technology or the fuel storage and delivery infrastructure.”

And Honeywell says that USAF F-15s and Thunderbirds have flown with these fuels in April and May 2011. In addition, serious research is being devoted to coal liquefaction using the Fischer-Tropsch (F-T) synthesizing process developed in Germany during the 1920s to make so-called “syngas.”

These new fuels are being developed in parallel with efforts to reduce contaminants in aviation fuel like sulphur a known environmental pollutant.16 And while the future looks promising for less polluting green fuels, new technologies are emerging in the fi ltration fi eld with Ultraclear’s attapulgite granules that are claimed to have a “large, highly active surface area that absorbs oil soluble surfactants, organometallic compounds such as copper-complexes, and particulate matter”.17

The Defense Advanced

Research Projects

Agency (DARPA) is

working on Vulcan, a

program to design, build

and demonstrate a full-

scale constant volume

combustion (CVC) power

generation turbine engine.



References:1 Aircraft Accident Report No: 1/2010 (EW/C2008/01/01)

2 Aircraft Accident Report No: 1/2010 (EW/C2008/01/01) p.166

3 Aircraft Accident Report No: 1/2010 (EW/C2008/01/01)


5 http://www.exxonmobil.com/AviationGlobal/ProductsServices/product_descriptions.asp

6 4.2 Safety Recommendation 2008-047: Aircraft Accident Report No: 1/2010 (EW/C2008/01/01)


8 Apple Jelly contaminant in Military Aviation fuel Sponsored by: Defense Energy Support Center (DESC) Product Technology and Standardization Division

9 DIEGME RESISTANT FUEL TANK COATING Michael E. Spicer & Uttara Mazumdar* Air Force Research Laboratory Coatings Technology Integration Offi ce (CTIO) 2700 D St., Bldg. 1661 Wright Patterson AFB, OH 45433 University of Dayton Research Institute 300 College Park Dayton, OH 45469-0146



12 Civil Aviation Authority of New Zealand

13 www.casa.gov.au/airworth/awb/28/003.pdf

14 Facing the Hard Truths about Energy –A Comprehensive View to 2030 of Global Oil and Natural Gas (2007)

15 Flightglobal: Jeffrey Decker Coal - jet fuel of the future?

16 QinetiQ for the European Aviation Safety Agency (EASA)

17 Ultraclear website

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resource for senior military and

defence industry professionals.

• Up to the minute Industry and Technology News and other content available to

all site users on a free of charge, open access basis.

• Qualified signed up members are able to access premium content Special

Reports and interact with their peers using a variety of advanced online

networking tools.

• Designed to help users identify new technical solutions, understand the

implications of different technical choices and select the best solutions

available.

• Thought Leadership - Advice and guidance from internationally recognised

defence industry key opinion leaders

• Peer Input - Contributions from senior military personnel and defence industry

professionals

• Independent Editorial Content - Expert and authoritative analysis from award

winning journalists and leading industry commentators

• Unbiased Supplier Provided Content

• Designed to facilitate debate

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special report – military aviation fuel filtration technology

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