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Dear Director,

After reading the final KNKT draft report KNKT.13.09.24.04 for the accident involving aircraft

PK-KFC I have following information to show the report was not conducted properly as all

information available was not used to create the report.

I feel the person who did the investigation left out key information to show the procedures

were wrong for our school and the procedure of leaning the aircraft was the only reason the

accident happened. The following information shows that the procedures used by this school

are in fact in accordance with the aircraft manufacturer and engine manufacturer approved

limitations and procedures.

Here is a list of the issues I have with the report.

Issue 1- Page 4. The Cessna Pilot Hand Book required rich mixture on takeoff except for the elevation more than 3,000 feet. Issue 1 Answer- In section 4 of the Cessna 152 operating manual page 4-14 under normal procedures for takeoff it states It is important to check full-throttle engine operation early in the takeoff run. Any sign of rough engine operation or sluggish engine acceleration is good cause for discontinuing the takeoff. If this occurs, you are justified in making a thorough full-throttle static runup before another takeoff is attempted. The engine should run smoothly and turn approximately 2280 to 2380 RPM with carburetor heat off and mixture leaned to maximum RPM. See Figure 1. The engine at maximum power can only produce 2280 to 2380 RPM. We had constant engine

roughness before each takeoff since the use of MOGAS began. This is found in the aircraft

maintenance documents and journey logs which justifies the pilot to lean the mixture for

maximum RPM before attempting a second takeoff.

In the Cessna POH in section 4 for Fuel Saving Procedures for Flight Training Operations paragraph 3 it states 3. Lean the mixture for maximum RPM during all operations at any altitude, including those below 3000 feet, when using 75% or less power. See Figure 2 The Lycoming Operators Manual for the Lycoming O-235 states that at 2800 RPM the engine

will produce 100% BHP and will only produce 75% BHP at 2500 RPM. These tests are conducted

at the standard temperature of 15C which will give higher performance numbers than at the

temperature/dew point at the time of the accident which was 25C/21C 1013 hpa and a

density altitude of 3334 at the indicated altitude of 1500 MSL. At sea level the weather was

reported at 28C/24C 1013 hpa and a density altitude of 2042 MSL. The weather information

was not included in the report from the KNKT. I have added the weather to this report for 12

September 2013 as figure 4.

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With a density altitude of 2042 MSL at takeoff, the airplane in the temperature of 28C could

only produce 70% BHP and well below the 75% bhp for leaning the aircraft

Issue 2 - Page 4 The investigation did not find the record of the performance record before and after the AVGAS to MOGAS. Issue 2 Answer All aircraft were repeatedly grounded for rough running engines beginning 09 June 2013. The conditions became worse and worse. Instructors and students began to complain to maintenance about the issue of the fuel. Maintenance informed the Principal that the fuel was causing the plugs to continuously foul. The response from the Principal was If someone wants to use Avgas they can pay for it. Here is a list of maintenance discrepancies by aircraft. This list was not included in the report to show there was a history of engine issues with all aircraft in the flight school.

PK-KFA:

On June9, June 10, June 11 and 12 the aircraft was squawked for loss of power. The cause of

the loss of power was the sparkplugs had deposits on them and needed to be cleaned. On 12

June the aircraft also had high oil temperatures.

On August 1 the aircraft was grounded for high oil temperatures and we removed and replaced

the Oil Cooler as we thought that may be the issue. PK-KFA continued to have high oil

temperatures after the new oil cooler was installed, but not in the red.

PK-KFB

On 30 August the aircraft was squawked for a rough running engine and the plugs were

cleaned.

On 11 September the aircraft was squawked for rough engine and the spark plugs were

removed and cleaned. The message I received via text from the instructor pilot was as follows

e have a problem with Charlieclmbing no more than 200 fpm and with full throttle in straight

and level no more than 2200 RPMcan we use alfa even if it is not dispatched? See Figure 8.

The constant removing and cleaning of the plugs caused the #1 cylinder plug hole to become

unserviceable and the aircraft was grounded until the heli-coil kit arrived to fix the aircraft. It

was down for 3 weeks.

PF-KFC

On 7 September the aircraft was grounded for loss of power and the Sparkplugs were cleaned.

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On 11 September the aircraft was squawked for loss of 200 RPM during the run up.

Maintenance replaced 2 sparkplugs and cleaned the others due to deposits on the sparkplugs.

On 12 September PK-KFC went down due to engine failure which was caused by detonation.

PK-KFF

On 28 July PK-KFF was grounded for right magneto dropping to many RPM during the run up

prior to take off. The mechanics replaced 4 spark plugs due to residue on them.

Issue 3 Page 10 Item m. There were no evident of engine performance record before and after changed the AVGAS to MOGAS. Issue 3 Answer As seen above from the maintenance reports from all of the aircraft performance was lost and several reports of power lost in flight. PK-KFC was grounded twice in the preceding five days due to engine roughness. Issue 4 Page 10 Item 5 The takeoff Fuel Mixture policy taken by management was differed with the Pilot Operating Handbook for Cessna 152 Issue 4 Answer - In the POH it states Lean the mixture for maximum RPM during all operations at any altitude, including those below 3000 feet, when using 75% or less power. This is the same POH that is in the aircraft now and is the same POH that the investigator used for his report. See figures 2, 5, 6, 7 Issue 5 No mention of the age of the fuel was mentioned in the report. Issue 5 Answer - See figure 7. Fuel was delivered to FlyBest Flight Academy was 24 April 2013. When I told the KNKT investigator on 5 November about the information I found he said he tested the fuel and found it to be of good quality. I told him that the fuel could not be good since Shell Global states that the fuel can only be stored for a maximum of three weeks. I explained to him that, at the time I thought the fuel was delivered in beginning of June and he said No the fuel can be stored up to 3 months. I asked him if he smelled and felt the fuel and he replied No. I asked him how the fuel can still be good if it was 4 months old at the time of the accident and he had no reply. After further investigation on my part I found the fuel was delivered on 24 April 2013. There is no way to track the lot number on the fuel drums and the Principal stated that fuel takes 2 weeks for delivery. If the fuel was produced in mid-April then the fuel at the time of the accident was 24 weeks old which is 1200% to 800% over the recommended fuel storage time of Shell and 200% over the storage time quoted by the KNKT investigator. No attempt to find out the date of manufacture was done for the fuel. In the report from Shell Global, Appendix C, MOGAS is not designed to be stored for long periods. Within the automotive world MOGAS is generally burned within a few weeks of production so storage stability is not a concern. However, if kept for longer periods, MOGAS can form sticky lacquers and gums that have the potential to result in fuel injector or carburetor malfunctions.

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The composition of Avgas is much more tightly controlled, allowing fuel to be kept for months without deterioration significant in aviation as it is not uncommon for an aircraft to be in a hangar for several months with fuel remaining in the tank. I have attached letters from the instructors stating what they found during the preflight inspections of all the aircraft. Appendix D. E. F. H. Issue 6 Page 13 Section 5 The accident pilot seem to be not really understanding the risk of lean the mixture below 3000 feet. Issue 6 Answer - The Instructor pilot had over 1000 hours in type at the time of the accident and over 2100 hours of total time. The instructor is fully aware of the results from improper leaning procedures. The instructor has flown for more than two years on small piston aircraft using MOGAS. See Appendix H. All of the instructors are aware of such results and if any of the instructors had felt this procedure was outside a safe operation then they would have expressed their disagreement with such procedures. Synopsis

During the initial part of our internal investigation that began on the 12th of September I stated to the head of maintenance and the Principal I want a component test on the fuel. It does not smell right or feel right. I want to make sure we do not have contaminated fuel. No report was ever conducted or no results were ever posted. During the investigation by the insurance company the investigator noticed that there was no

scoring or scratches on the inside of the number 2 cylinder, see Figure 3, which was caused due

to the fact that the engine stopped running instantly after the detonation happened and did

not happen during the climb or over a long period of time. The loss of power was reported the

day before as noted above. In the report from the Light Aircraft Association it states If on the

other hand the fuel vaporizes from some hot spot or low pressure area in the fuel system but

does not become entrapped, a stream of vapor bubbles will enter the carburetor along with the

fuel, causing raised EGTs, lean running and reduced power, which in the typical fixed pitch

propeller installation is evidenced by a loss in indicated rpm and possibly puffs of white smoke in

the exhaust. The procedure of leaning of the engine was not the issue of the detonation or

engine failure of the engine. The procedure of leaning the engine has been in place since the

school started operating in January and none of these symptoms began until June when we

began using the MOGAS.

Lidia Roset, the instructor of the flight where the engine failed, said that when the engine

began to lose power she added mixture rich. The engine did not fail. When she applied full

throttle the engine instantly stopped. This was caused by partial vapor lock of the carburetor.

When she added full power as instructed to do by the Emergency checklist during an engine

failure it further leaned the engine as more air was added to the fuel to air mixture. Without an

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Exhaust Gas Temperature gauge on the aircraft Lidia Roset was unable to tell the EGT of the

engine and therefore followed the emergency checklist perfectly. The partial vapor lock with

the addition of throttle caused the detonation.

Every aircraft was noted to have a reduction in performance later as the fuel was continued to

be used. All the pilots and maintenance noticed the fuel was sticky and had a funny smell to it

as of June.

Maintenance said that when the MOGAS fuel drums arrived they had corrosion and looked very

old and faded.

Since we started using the MOGAS we have replaced a total of 12 Sparkplugs due to deposits

on the sparkplugs. Since September 13th 2013 when we returned to using straight Avgas we

have not had to replace any sparkplugs.

All of the symptoms stated above are from old fuel and started in June when using the old

MOGAS we have in stock. All the squawks are from the aircraft journey logbooks and Flight

Schedule Pro maintenance discrepancies. Every symptom associated with old fuel is present in

the historical data of the aircraft and it all started in June through September using both mixed

MOGAS/AVGAS and straight MOGAS. The mixing of AVGAS into the fuel we have now cannot

be done as we cannot prove that it will make the fuel safe for use. According to the

information we have this practice will not fix the issue as the report from the Light Aircraft

Association states Assuming that your aircraft is cleared for use with both unleaded Mogas and

with Avgas 100LL, there is no problem with mixing fuel of both types in your tank. Note

however that even with just a small proportion of Mogas in the tank, the vapour pressure of the

mixture will be almost as high as that of pure Mogas, so all running on a mixture containing

Mogas must be carried out observing the operating limitations for unleaded Mogas alone.

Prior to the use of the MOGAS we had no indication of abnormal engine operations. There

were several other instances where the maintenance was alerted to a rough running engine

and they cleaned the sparkplugs after the use of the MOGAS began. Almost every flight we had

to clear the magnetos due to a rough running engine to remove deposits from the sparkplugs.

When I asked the principal how long it took for fuel to arrive from the time it was ordered she

said it takes about a week. I cannot verify the date of manufacture of the fuel we have

received so far.

When I asked the maintenance engineers why we kept using the fuel when it was thought to be

the cause of these issues I was told that they had notified you several times about the fuel

being an issue and they were told it was too expensive to use AVGAS and that if they wished to

use such fuel someone else would have to pay for it.

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Since we have switched back to pure AVGAS we have had only one issue of power loss from an

aircraft and that was during flight when power was reduced below 2000 RPM during a day with

very high humidity which caused the carburetor to develop carburetor icing. No student pilots

or instructors have had to clear the magnetos to burn any deposits off the spark plugs since we

have changed to pure AVGAS.

Considering that the fuel was received on 24 April, see figure 7, and can only be stored only a

few weeks, according to Shell Global, see figure 1, before it goes bad I cannot allow the MOGAS

we have in stock to be used in the aircraft no matter what we mix it with. There will be no way

to guarantee the safety of flight with such fuel in the aircraft. The following reports give every

indication we have seen in our aircraft since we first started using the fuel in April.

Conclusion

With this knowledge and the research I have given to you by Light Aircraft Aviation group, see

figure 1, and Shell Oil Company, see figure 2, and the Civil Aviation Authority of the UK See

Appendix B stating that the fuel should not be used above 20C due to the volatility being

higher, and the chance of vapor lock happening as well as carburetor icing, the symptoms of old

fuel, and the fact that the fuel we have in stock was received in April 2013, I sent an email to

the Principal, Appendix G, on 25 October 2013 with a report stating that FlyBest cannot use

MOGAS anymore , even the MOGAS we have in stock and a different solution needs to be

found, see appendix G. I received no response from the Principal. On 3 December I resent the

same email and report and on the 5th of December I received the response I fwd to Capt Budhi.

I am already busy with yearly report and budgeting things. See appendix H.

The argument of financial savings for the company using MOGAS instead of using AVGAS

weighs heavily towards AVGAS. During the months of January until June we never had an

aircraft down or squawked for engine issues. Between June 9th and 12 September we lost a

total of 99 flying days due to aircraft on the ground for engine roughness issues. That is a loss

of around 400 flight hours. The cost of 12 sparkplugs of $29.83 each or, a total of around $358

and around 400 man hours due to the use of the MOGAS and the loss of an aircraft reducing

our fleet by 20% is not efficient and is actually very expensive.

This counter report is submitted to you for your reference.

Denis Boissonneault

Chief Flight Instructor

FlyBest Flight Academy

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Appendix A - Figures *1 See Appendix B - Light Aircraft Association Report

*2 See Appendix C Shell Global Technical Aritcles

Appendix D - Raymond Duquesnays letter about aircraft performance.

Appendix E - Stefano Marras letter about aircraft performance.

Appendix F - Lidia Rosets Letter l about aircraft performance.

Appendix G - Email to Karin Item about MOGAS usage.

Appendix H Email response from Karin Item about MOGAS usage.

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Appendix A

Figure 1

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Figure 2

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Figure 2 Continued

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Figure 3

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Figure 4

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Figure 5

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Figure 6

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Figure 7

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Figure 8.

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Appendix B

OPERATING INFORMATION UNLEADED MOGAS Issue 6. dated: 26th May 2009 This information is only applicable to LAA aircraft and only those airframe/engine combinations specifically cleared by the LAA for use with unleaded fuel. This document is to be attached as an addendum to the Flight Manual or Pilots Notes of the aircraft concerned or, in the absence of these, stapled within the airframe logbook. 1. Obtaining and Storing Mogas It is essential that the type of unleaded fuel used is to BS EN 228 and is the 95 RON Premium Unleaded type. Check the markings at the fuel pump. LAA have not investigated the older BS7070 specification fuel, which is sometimes seen at the pumps although it is now superseded. On no account use Four Star Lead Replacement Fuel which may be adequate for gentle road-going use but is not suitable for aircraft, in which the engine has to run continuously at high power setting. It is always preferable to buy Mogas for aircraft use from a supply at an airfield or a garage with a reasonably high turnover and from a reputable supplier. We have come across problems in the past with cut-price supermarket fuel of poor quality. In recent years, due to pressures from the Green lobby to use bio-fuel, some petrol supplied through the forecourts has had varying amounts of alcohol added to it. The proportion of alcohol added is gradually increasing over time and the number of outlets supplying alcohol laced petrol is also increasing. Alcohol in the fuel can damage the rubber components in the fuel system, and also cause problems through progressively absorbing water which can suddenly come out of solution later, flood the water trap and fuel sump and stop the engine in flight. CAP 747, Appendix 8, General Concession 5 makes it mandatory to check that unleaded Mogas fuel does not contain alcohol before it is used in any group A aeroplane. The test method for detecting alcohol in petrol as described in the CAA Safety Sense leaflet 4b is not sensitive to alcohol levels of 5% or less, the current maximum level likely to be found, therefore a test kit has been developed that enables the detection of alcohol down to around 1%. Alcohol detection test kits are available from Airworld UK Ltd.

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Always store fuel in suitable clean containers. CAA requires that fuel containers may be either metal, of up to 23 litres capacity and fitted with a secure leak-proof cap (Jerry can) labelled Petroleum Spirit, highly inflammable or if plastic, it must be made for the purpose (complex regulations refer) and of no more than 5 litres capacity. We are advised that the Road Traffic regulations normally applicable to carriage of petrol by road do not apply if the fuel is being carried for recreational purposes. No more than four containers, which must be made specifically for the carriage of petrol and have a maximum capacity of 20 litres each, may be carried. If fuel is kept only for leisure purposes, we understand that up to 270 litres may be stored in one premises before having to apply to the County Council Petroleum Officer for a license. Nevertheless if more than 15 litres is stored then there is a legal obligation to inform the Petroleum Officer who must inspect and approve the premises. He will require the fuel store to be adequate for the job and to be equipped with a suitable nearby 6 Kg dry powder fire extinguisher. On the other hand, there is no requirement to contact the Petroleum Officer if the fuel is stored in the fuel tank of the aircraft itself. Nevertheless you should use common sense and also consider the implications regarding buildings insurance etc. Apart from the obvious safety considerations, due to the short shelf life of Mogas fuel you are advised not to store large quantities. You are far better off purchasing small quantities of fuel as and when required, which will ensure that you always use fresh fuel blended appropriately for the time of year see section 7 below. 1. Records of Purchase Find a reasonably substantial envelope and write the aircrafts registration and the year on it. Each time you buy unleaded fuel for your aircraft put the receipt in the envelope. At the start of the next year, treat yourself to a new envelope and put the old one into store for at least a further year. After that year has elapsed you can then throw the old one away. The above procedure has been agreed by the CAA to meet the intent of the Airworthiness Notices. 1. Quality Checks Despite the lack of aviation-type quality control measures, over the years that four-star Mogas was being used in aircraft there were few reports of problems due to contaminated fuel from garage forecourts. It is likely that this record will continue to improve due to more stringent standards of underground tank installations and special tank connections to preclude the possibility of the underground storage tanks being filled with the wrong type of fuel. Nevertheless this is no excuse for lesser vigilance on the part of the pilot, and all Mogas fuel

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should be poured into the aircraft via a fine-mesh or chamois leather filter, and carefully sampled in the normal way. Watch out for flakes of paint in the fuel from the insides of metal Jerry cans. (When fuelling and de-fuelling, guard against flash fires by electrically grounding the tank, funnel and can before transferring the fuel, and avoid a brimming funnel. If the stream of fuel from the source encounters the fuel in the receiver inside a closed container, the fuel/air mixture will almost certainly be too saturated to cause a fire should a spark occur. If, on the other hand, the fuel stream encounters a brimming funnel in free air then the petrol vapour in the vicinity may well be in the critical region where the tiniest spark will cause a flash fire). If the aircraft has been standing for 24 hours or longer, check that the fuel has not become contaminated with water before flight. It is generally preferable to keep tanks full whenever possible to minimise water condensation the only exception being in hot weather when there may be a risk of the fuel becoming heat soaked and causing vapourisation problems see section 7 below. Only use fresh supplies of fuel and after a period of protracted storage, drain out any old fuel from the tank before filling up with fresh. Over a long period of time the fuel in the tank will evaporate away the more volatile fractions through the tank vents, leaving a residue of low-volatility fuel which will cause poor starting, reduced performance and possibly engine damage through detonation or over-heating. When in storage, Mogas fuel has a much greater tendency to form gum deposits than Avgas, so it has a much more limited shelf life of just a few weeks. Avgas on the other hand can be kept in sealed drums for several years. Gum deposits can block carburettor jets and cause moving parts to stick. Even if your engine appears to start and run well on last seasons fuel, you should drain it off and replace with fresh. Mogas fuel is also blended differently in the summer to that in the winter, to promote easy starting and driveability. Using summer fuel in winter may cause difficulty in starting, while using winter fuel in summer will increase the likelihood of vapour problems (see section 7. below) 1. In Use Except as described below, you should find no difference in operation when you transfer from four-star to unleaded, except perhaps a slight change in the colour of the grey exhaust pipe deposits and less tendency toward plug fouling. 1. Operating Limitations Unleaded Mogas fuel is restricted by CAP 747, Appendix 8, General Concessions 4 and 5 to operation with a fuel not exceeding 20 C and an altitude not exceeding 6000 ft. These additional limitations must be displayed in the cockpit using a suitable placard (see section 6 below).

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Special steps may be needed to prevent the fuel tank temperature exceeding 20 C, especially during summer. Avoid letting the aircraft heat soak in the sun for long periods before flight, especially if the part containing the tank is painted a dark colour. On a hot sunny day, avoid parking the fuelled-up aircraft on dark tarmac surfaces. Consider instead filling the tank with cold fuel shortly before take-off, or better still, leave in the cool of morning rather than after a prolonged soak in the midday sun. Assuming that your aircraft is cleared for use with both unleaded Mogas and with Avgas 100LL, there is no problem with mixing fuel of both types in your tank. Note however that even with just a small proportion of Mogas in the tank, the vapour pressure of the mixture will be almost as high as that of pure Mogas, so all running on a mixture containing Mogas must be carried out observing the operating limitations for unleaded Mogas alone. 1. Placards A placard must be fitted alongside each fuel filler stating as follows: UNLEADED MOGAS BS EN228, 95 RON A placard must be fitted on the instrument panel, or other location in clear view of the pilot in flight, stating:

USE OF UNLEADED MOGAS (see CAP 747, Appendix 8, General Concessions 4 and 5) -only legal in aircraft specifically approved for the purpose -fuel to be fresh, clean, water and alcohol free -verify take-off power prior to committing to take-off -tank temperature not above 20 C -fly below 6000 ft CARB ICING AND VAPOUR-LOCK MORE LIKELY

Placards as above are available from LAA Engineering, free of charge to LAA members. 1. What about Vapour Lock ? Unleaded Mogas, like the obsolete four-star Mogas fuel, has a much higher vapour pressure than 100LL or 80/87 Avgas. The initial boiling point of the fuel is only slightly above ambient temperature, so it takes only a slight raise in temperature or drop in pressure to make it start to vapourise. This unfortunate property of Mogas makes it much more likely to suffer vapour-lock or vapourisation problems than Avgas, especially in hot weather or at high altitude. Hence the limitations to 20 C and 6000 ft altitude which apply to Mogas use, and the requirement to check that full engine power is available before committing to a take-off. These special power checks should not be rushed, as they also serve to burn off the fuel which may have become

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pre-warmed in the fuel pump and gascolator while the engine has been idling, and drawing fresh, cool fuel through from the tank which will be less likely to cause vapour problems on take-off. When the fuel turns to vapour in the fuel system, this can cause a number of different problems and it is important for Mogas users to understand the implications. If the vapour collects and forms a large bubble which becomes entrapped at a high point or constriction in the fuel pipe, this can form a vapour lock, effectively preventing the passage of fuel to the engine and causing a dead cut similar to what would happen if you were to turn off the fuel cock. If this should occur, FLY THE AEROPLANE, lower the nose, and if sufficient height is available in which to experiment, turn on an auxiliary fuel pump if you are fortunate enough to have one, and select another fuel tank. If the auxiliary fuel pump is already on, you might try turning it off. If on the other hand the fuel vapourises from some hot spot or low pressure area in the fuel system but does not become entrapped, a stream of vapour bubbles will enter the carburettor along with the fuel, causing raised EGTs, lean running and reduced power, which in the typical fixed pitch propeller installation is evidenced by a loss in indicated rpm and possibly puffs of white smoke in the exhaust. With Mogas, when carrying out the special power check prior to committing to take off you should be looking and listening not only for signs of uneven running but also an rpm which is less than normal on the tachometer, either during the run-up or during the initial stages of the take-off run. If either of these signs of vapourisation occur, you MUST abandon the take-off as the symptoms may well worsen as the engine heats up, and the power level may fall away to nothing during the climb-out. If vapourisation is suspected in flight, FLY THE AEROPLANE, lower the nose to maintain airspeed, reduce the throttle setting so that the airflow into the engine is reduced to correspond with the enfeebled fuel flow, and richen the mixture control (if fitted) which should at least restore the fuel mixture strength, smooth running and possibly yield a few extra rpm. Since the symptoms may also resemble those associated with carburettor icing, carburettor heat may be required although this may have an adverse effect on fuel vapourisation problems and you will need to experiment to identify the cause of the problem before you can cure it. Vapour problems are most likely to occur in aircraft fitted with engine-driven mechanical fuel pumps, and are rarely experienced with a purely gravity-fed system or those with an electric fuel pump situated at the tank outlet or, better still, submerged in fuel within the tank itself as in modern automotive practise. Unfortunately, in the typical aircraft system the fuel pump is located above the fuel tank, so the fuel pressure on the upstream side of the fuel pump is reduced below atmospheric by the action of the pump sucking up the fuel, making it very vulnerable to fuel vapour formation on the inlet side of the pump, with symptoms as described above. If the engine is fitted with a mechanical pump, bolted to the engine crankcase, then heat conducted into the pump from the engine block will raise the temperature of the pump body significantly and only the flow of cool fuel through the pump keeps the pump temperature

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moderate. When the engine is shut down after a flight, the cooling airflow through the engine compartment ceases along with the flow of cool fuel through a mechanical engine-driven pump. As a result the pump body temperature can rise alarmingly and particularly when using the more volatile Mogas, you may hear the fuel in the pump boiling. You may then notice the engine dripping fuel from the intake drain onto the ground, due to the vapour pressure of the boiling fuel pushing the contents of the carb float chamber past the float valve and into the venturi. To cool the engine compartment after shut-down it may help to open cowling hatches and prop them open to promote convective airflow through the engine compartment. Remember to latch them down before flight though. If the fuel should vapourise within the fuel pump due to elevated pump temperature, the fuel vapour generated inside the pump body cannot escape back into the fuel system upstream, because of the one-way valve on the intake side of the pump. So instead, the vapour expands past the outlet valve of the mechanical pump, in so doing pressurising the fuel in the fuel pipe and carburettor float chamber, causing a so-called pneumatic lock. The vapour pressure of the boiling fuel is enough to push the fuel past the carburettor float valve and the engine suffers a rich cut, with raised fuel pressure indications, rough running and characteristic sporadic black puffs of exhaust smoke. The most likely time this will occur is when the aircraft is flown, landed, parked for a short time and then a second take-off is made. If this should occur in flight, FLY THE AEROPLANE, lower the nose to maintain airspeed, reduce the throttle setting to that appropriate to level flight and attempt to restore smooth running by leaning the mixture. If your aircraft has a mechanical pump with a back-up electric pump connected in parallel, then it is important not to switch the electric pump off too early after take-off, especially with Mogas, as there is a risk that the fuel in the mechanical pump may have been stagnant and vapourised away while running on the electric pump, in which case the engine will stop as soon as the electric pump is switched off. Fuel suppliers provide higher volatility fuel in winter to help cold-starting. Be particularly wary of vapour problems in spring and autumn months when winter fuel is being supplied but ambient temperatures may be moderately high. A simple piece of test equipment is available which allows the pilot to test the volatility of his fuel and likelihood of vapour problems during the pre-flight check. This is known as a Hodges volatility tester, and is available at a modest price from Petersen Aviation Inc. in the USA, tel. 001-308-832-2050. 1. Carburettor Icing The greater volatility of Mogas compared to Avgas means that the carburettor throat temperatures are lowered more by the atomisation of Mogas at the jet than occurs with Avgas. Tests by the BGA showed that with the same ambient conditions, the carb throat temperatures

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of a Lycoming 0-360 were typically 7 C lower with winter grade Mogas than Avgas. The result is that when using Mogas, carburettor icing will occur under higher ambient temperature conditions and lower humidity than with Avgas. Take particular care to check the efficiency of any carburettor heating provisions and to watch out for signs of carburettor icing in flight. When using Mogas, use carb heat more frequently and for a longer period than normal especially on days when carburettor icing is likely refer to CAA Safety Sense Leaflet on the subject. Carburettor ice remains a frequent cause of engine failures, which suggest that fitting a proprietary ice detector system to the carburettor may give a useful safety benefit. 1. Chemical Compatibility During the daily check and other routine inspections, pay particular attention to non-metallic fuel pipes, fuel valves etc for signs of leaks due to chemical attack from the fuel. There is a possibility that rubber pipes, seals, gaskets, O-rings, fuel tank sloshing sealants and even the varnish on cork fuel gauge floats may be affected by constituents within unleaded fuel. Standard MS29513 aviation O-rings swell significantly in size when in contact with unleaded Mogas, which may affect the operation of fuel valves, gascolators, fuel filler cap seals etc. All these points should be borne in mind during your pre-flight checks. You should also check filters frequently for signs of contamination either from the fuel or resulting from chemical attack on fuel system components or the fuel tank. Viton rubber is unaffected by unleaded fuel. O-rings of Viton rubber are available from specialist seal suppliers. 1. Continental and Lycoming Engines With these engines, many of which were originally produced many decades ago, there have been a variety of different valve seat and valve materials used over the years, and there is a possibility that some combinations in the field might suffer problems with valve seat recession if deprived of the dry-lubricating effect of tetraethyl lead in leaded fuels. To guard against this possibility it is recommended that all users of Continental and Lycoming engines cleared for unleaded Mogas use should either use a fuel mixture with 10% 100LL in it or run a tankful of 100LL through the engine at least every 75 running hours to lubricate the valves and valve seats. If you have the engine top overhauled or majored, it is recommended that you run the engine on 100LL Avgas for the first 10 hours operation afterward to ensure adequate lead content during the break-in period. Due to the likelihood of 100LL being withdrawn in the not too distant future for environmental reasons, it is recommended that when Continental or Lycoming engines come to be

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overhauled, the cylinder assemblies are replaced with new assemblies known to be compatible with unleaded fuel, which will not require this occasional doping with leaded fuel. Some Marvel-Schebler (latterly, Facet and now Precision Airmotive) carburettors may still be fitted with moulded cellular rubber floats, as introduced by FAA AD 66-05-04 (withdrawn in 1985). Some of these floats have given trouble due to soaking up fuel, loosing buoyancy and dropping in level, causing rich running problems, i.e. flooding carburettor, rough running at idle speed and inconsistent shutdown. Facet Service Bulletin A1-84 refers. While the composite floats are no more likely to absorb unleaded Mogas than they are 100LL fuel, owners should be wary of this problem and if problems are experienced, consider fitting a replacement float (Precision Airmotive Service Information Letter SIL MS-4). Some Bendix NAS-3 carburettors may still be fitted with obsolete synthetic rubber-tipped needle valves, which should have been replaced with a Delrin-tipped needle under Bendix Aircraft Carburettor Service Bulletin ACSB-84. While Bendix advise that their own original neoprene-tipped valves should not cause any trouble if used with unleaded Mogas fuel (and this seems to be confirmed by the LAAs submersion tests) a problem has been reported in the USA with bogus neoprene tipped valves which swelled up when submerged in fuel and caused excessively lean engine running. The bogus valve tips respond equally when submerged in 100LL fuel. Nevertheless, owners should be aware of this potential problem if they suspect that the neoprene-tipped valves are still fitted. 1. Rotax 912, 912S and 914 Engines The Rotax 912, 912S and 914 engines have been designed to run on unleaded Mogas however a vapour return line must be fitted to the fuel system in accordance with Rotax recommendations. If the aircraft is not already fitted with one of these, one must be fitted to a scheme acceptable to LAA Engineering. 1. Rotax 2 Stroke Engines Rotax 2 stroke engines are designed to use unleaded fuel and you should find no difference in operation when you transfer from four-star to unleaded, except perhaps a slight change in the colour of the grey exhaust pipe deposits and less tendency toward plug fouling. Unleaded Mogas, like four-star fuel, has a much higher vapour pressure than 100LL Avgas. Consequently it is much more likely to suffer vapour-lock problems causing engine power failure, especially in hot weather and high altitude. Hence the limitations to 20 degrees C and 6000 ft altitude which apply to Mogas use, and the requirement to check that full engine power is available before committing to a take-off.

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Fuel suppliers provide higher volatility fuel in winter to help cold-starting. Be particularly wary of vapour lock in the autumn months when winter fuel is being supplied but ambient temperatures are still high if we are lucky enough to enjoy an Indian summer. Engines running on unleaded Mogas fuel are more likely to suffer carburettor icing than when running on 100LL. Take particular care to check the efficiency of any carburettor heating provisions and to watch out for signs of carburettor icing in flight. During the daily check and other routine inspections, pay particular attention to non-metallic fuel pipes, fuel valves etc for signs of leaks due to chemical attack from the fuel. Check filters frequently for signs of contamination either from the fuel or resulting from chemical attack on fuel system components or the fuel tank. 1. Jabiru Engines Jabiru warn that although their engines may be operated on 95 UL Mogas provided the compression ratio is not more than 8.3, there is nevertheless an increased risk of detonation when unleaded is used rather than 100LL Mogas. An installation which is marginal with regard to cylinder head cooling may suffer problems with detonation and engine damage when transferred to Mogas fuel. Be particularly wary of any signs of detonation, warped or leaking heads which may be a sign of detonation occurring which, if left unchecked, are likely to result in major engine damage and in-flight engine failure. 1. VW and VW based Engines VW and VW based engines are suitable for 95 UL Mogas use, provided that the engines compression ratio does not exceed 8.0:1 although there is the possibility that engines not fitted with hardened valve seats may suffer from rapid valve seat recession if deprived of the dry-lubricating effect of tetraethyl lead in leaded fuels. To guard against this possibility it is recommended that all users of VW and VW based engines cleared for unleaded Mogas use should either use a fuel mixture with 10% 100LL in it or run a tankful of 100LL through the engine at least every 10 tankfuls to lubricate the valves and valve seats. Checking the compressions by turning the propeller by hand should give an indication if valve seat recession has become excessive, but the valve clearances must be measured at least once every 25 hours and adjusted if the clearance is found to be on or out of limit. Excessive exhaust valve clearance will introduce the possibility of valve burning which may lead to engine failure. If you have the engine top overhauled or majored, it is recommended that you run the engine on 100LL Avgas for the first 10 hours of operation afterward to ensure adequate lead content during the break-in period. Due to the likelihood of 100LL being withdrawn in the not too distant future for environmental reasons, it is recommended that when VW and VW based engines come to be overhauled, the

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cylinder assemblies are replaced with new assemblies known to be compatible with unleaded fuel, which will not require this occasional doping with leaded fuel. 1. If Problems Occur While the foregoing is based on the best information available at the time, ultimately Mogas supply is not as tightly controlled as Avgas and there is therefore more scope for problems of contamination or mis-identity. No guarantee can be given that fuel is of the type specified on the pump, and only by constant vigilance can safety standards be maintained. Remember that the CAA continues to take the view that engine failure is always a possibility in single-engined aircraft. Consequently the pilot has a duty to operate it in such a way that engine failure would not case a hazard either to himself, his passengers or third parties on the ground. If engine problems occur which appear to relate to fuel type or fuel contamination, contact the CAA as described in the Airworthiness Notices along with copies of the appropriate fuel receipts. 1. Further Information Much further information about the use of unleaded Mogas is available from the websites of

Petersen Aviation (www.webworksltd.com/webpub/PetersenAviation) and the EAA

(www.eaa.org).

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Appendix C

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The original online document is located at:

http://web-dev2.shell.com/global/products-services/solutions-for-

businesses/aviation/aeroshell/knowledge-centre/technical-talk/the-blue/issue-6-2007.html

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Appendix D

Re: Mogas as used by Flybest Flight Academy When we first started flying the planes here in Batam, we were using Avgas. We found generally, that the planes performed very well, delivering very close to book performance figures. There was never a chronic problem with plug fouling. Only rarely did we have to clear plugs after startup. And at no time was it severe enough that the mechanics needed to pull plugs to clean them. After the switch to Mogas, we all noticed an oily feel to it. I once remarked to the Chief Flight Instructor that it smelled familiar, but couldn't think what the small was, maybe like paint thinner, or toluene . Within the first week, I found I had to clear the plugs after EVERY startup. I began to wonder if this mogas was the same as the mogas in the USA or England. Also, I found we had more contaminants in the fuel whenever we checked the tank contents as required before every flight. Eventually, I was forced to cancel flights because even the plug clearing procedure would no longer get the engine to run smoothly. The mechanics had to manually clean the plugs. I suspect every day. Eventually, this caused us to lose the use of one aircraft, due to repeated removal of the plugs from the engine to clean. Resulting in Murphy's Law reaching out to us... one of the cylinders was found with damaged threads in the spark plug hole, taking a long time for the parts for the repair to reach us, grounding the aircraft. I also started to see what looked like an oily yellow liquid in the fuel samples taken during preflight, forcing us to drain up to half liter of fuel sometimes to get clean fuel from each fuel testing point. Every single engine start, began to require plug clearing in order to run smoothly... And more than once only to run poorly before take-off and force us to cancel another flight while the technicians did their drill....i.e. pull and clean plugs manually. After a while, I noticed the engines starting to not run as smoothly as they used to, occasionally giving little hick-ups while in cruise and other configurations. I guessed at the time it may have been a little water that escaped sumping. When reported to the mechanics, they checked what they could, found nothing wrong and returned aircraft back to service. I fully expect that if we return to mogas, we will definitely lose another aircraft. And this time, we may not be so lucky.

Raymond Duquesnay

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Appendix E

From: Stefano Marras Flight Instructor Date 8 December 2013 To: Denis Boissonneault, Chief Flight Instructor Sunject: Mogas Report Following the request from the Chief Flight Instructor of the Flybest Flight Academy regarding my personal opinion about the quality of the Mogas fuel used during the flight operations I'll state as follow: Since the very first day of the usage of the Mogas in the airplane I personally noticed and notified to the Chief the unusual properties of the fuel. Especially when we were draining the fuel I noticed it was unusually oily and greasy and most of the time it was contaminated with bubbles of a yellow oily substance. Sometimes was necessary to drain the fuel several times in order to eliminate entirely the problem before the flight. After the completion of the draining operations the fuel strainer was most of the time unusually oily: little oily bubbles were present all around the inner part of the strainer causing my concerns (discussed several times with my colleagues) because those bubbles were very persistent to be removed so very likely the same was happening inside the cylinders with potential unsafe outcomes... At the same time of the usage of the mogas I started to notice a change in performance of all the airplanes and, as reported on the journey log, I begun to experience problems during the starting operations, engine run-up operations and magneto checks. They were unusual especially considering how often those kind of problems were rising. After few days from the first flight with the mogas, as reported on the journey log, I experienced a significant loss of power of the engine immediately after takeoff with KFA but the same type of problems showed up later with the same characteristic few weeks later with all the other airplanes with a tendency to get worse. Concluding I like to highlight the fact that in my previous experiences (where I was flying always with Avgas either in Italy and /or in the US) I never experienced similar problems with any airplane that I flew. Stefano Marras

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Appendix F

From: Lidia Roset Soler Flight Instructor Date 8 December 2013

To: Denis Boissonneault, Chief Flight Instructor Sunject: Mogas Report

As I said in September in DGCA meeting, I flew in Greece for almost two years using MOGAS in Cessna

and Pipers airplanes. During all this time in Greece I never had any problem with fuel or airplanes.

The MOGAS used in Greece, was yellow and the smell and the feeling was completely different that the

one in Batam. The Greek company bought every day fresh.

0 MOGAS in a little gas station close to the airport.

The weather in Greece is different than in Batam. Greece has four seasons, during winter and fall the

temperatures are very low, but during spring and summer time the temperatures are very high. In

Thessaloniki around 40 degrees Celsius and the humidity 90 per cent

The first thing that I notice when I came to Batam is the difference between the MOGAS used in Greece

and in Indonesia, not only in the color, smell and texture, as well in the problems that we have in all the

starts, cleaning plugs over and over again

I hope my previous experience with the MOGAS help to clarify things

Lidia Roset Soler

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Appendix G

MOGAS Use.docx

Karin, 25 October, 2013

I thought much about our discussion with regards to the 3 packets of information about the

MOGAS that I gave to you on Tuesday 22 October. Considering that the fuel was received in

June and can only be stored only a few weeks before it goes bad I cannot allow the MOGAS we

have in stock to be used in the aircraft no matter what we mix it with. There will be no way to

guarantee the safety of flight with such fuel in the aircraft. The reports I showed you give every

indication we have seen in our aircraft since we first started using the fuel in June.

PK-KFA:

On June9, June 10, June 11 and 12 the aircraft was squawked for loss of power. The cause of

the loss of power was the sparkplugs had deposits on them and needed to be cleaned. On 12

June the aircraft also had high oil temperatures.

On August 1 the aircraft was grounded for high oil temperatures and we removed and replaced

the Oil Cooler as we thought that may be the issue. PK-KFA continued to have high oil

temperatures after the new oil cooler was installed.

PK-KFB

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On 30 August the aircraft was squawked for a rough running engine and the plugs were

cleaned.

On 11 September the aircraft was squawked for rough engine and the spark plugs were

removed and cleaned.

PF-KFC

On 7 September the aircraft was grounded for loss of power and the Sparkplugs were cleaned.

On 11 September the aircraft was squawked for loss of 200 RPM during the run up.

Maintenance replaced 2 sparkplugs and cleaned the others due to deposits on the sparkplugs.

On 12 September PK-KFC went down due to engine failure which was caused by detonation.

With regards to the accident of PK-KFC and the question of leaning procedures, the density

altitude the time of the accident was 1700 feet. When the engine experienced the detonation

it was at 1500 feet AGL which would have put the aircraft at a density altitude of 3200 feet.

Lycoming recommends leaning the engine above 3000 feet. During the investigation by the

insurance company the investigator noticed that there was no scoring or scratches on the

inside of the number 2 cylinder which was caused due to the fact that the engine stopped

running instantly after the detonation happened and did not happen during the climb or over a

long period of time. The loss of power was reported the day before as noted above. In the

report from the Light Aircraft Association it states If on the other hand the fuel vapourises from

some hot spot or low pressure area in the fuel system but does not become entrapped, a stream

of vapour bubbles will enter the carburettor along with the fuel, causing raised EGTs, lean

running and reduced power, which in the typical fixed pitch propeller installation is evidenced by

a loss in indicated rpm and possibly puffs of white smoke in the exhaust. The procedure of

leaning of the engine was not the issue of the detonation or engine failure of the engine. The

procedure of leaning the engine has been in place since the school started operating in January

and none of these symptoms began until June when we began using the MOGAS.

PK-KFF

On 28 July PK-KFF was grounded for right magneto dropping to many RPM during the run up

prior to take off. The mechanics replaced 4 spark plugs due to residue on them.

Synopsis

Every aircraft was noted to have a reduction in performance later as the fuel was continued to

be used. All the pilots and maintenance noticed the fuel was sticky and had a funny smell to it

when we first started using the MOGAS fuel from the first day of use.

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Maintenance said that when the MOGAS fuel drums arrived they had corrosion and looked very

old and faded.

Since we started using the MOGAS we have replaced a total of 12 Sparkplugs due to deposits

on the sparkplugs.

All of the symptoms stated above are from old fuel and started when we started using the

MOGAS we have in stock. All the squawks are from the aircraft journey logbooks and Flight

Schedule Pro maintenance discrepancies. Every symptom associated with old fuel is present in

the historical data of the aircraft and it all started in June through September using both mixed

MOGAS/AVGAS and straight MOGAS. The mixing of AVGAS into the fuel we have now cannot

be done as we cannot prove that it will make the fuel safe for use. According to the

information we have this practice will not fix the issue as the report from the Light Aircraft

Association states Assuming that your aircraft is cleared for use with both unleaded Mogas and

with Avgas 100LL, there is no problem with mixing fuel of both types in your tank. Note

however that even with just a small proportion of Mogas in the tank, the vapour pressure of the

mixture will be almost as high as that of pure Mogas, so all running on a mixture containing

Mogas must be carried out observing the operating limitations for unleaded Mogas alone.

Prior to the use of the MOGAS we had no indication of abnormal engine operations. There

were several other instances where the maintenance was alerted to a rough running engine

and they cleaned the sparkplugs after the use of the MOGAS began. Almost every flight we had

to clear the magnetos due to a rough running engine to remove deposits from the sparkplugs.

When I asked you how long it took for fuel to arrive from the time it was ordered you said it

takes about a week. If you want to test the fuel and the results take another week that will put

the use of fuel to only one week until we have to dispose of it due to the end of its shelf life of 2

to 3 weeks. I cannot verify the date of manufacture of the fuel we have received so far.

When I asked the maintenance engineers why we kept using the fuel when it was thought to be

the cause of these issues I was told that they had notified you several times about the fuel

being an issue and they were told it was too expensive to use AVGAS and that if they wished to

use such fuel someone else would have to pay for it.

Since we have switched back to pure AVGAS we have had only one issue of power loss from an

aircraft and that was during flight when power was reduced below 2000 RPM during a day with

very high humidity which caused the carburetor to develop carburetor icing. No student pilots

or instructors have had to clear the magnetos to burn any deposits off the spark plugs since we

have changed to pure AVGAS.

Conclusion

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With this knowledge and the research I have given to you by Light Aircraft Aviation group *1

and Shell Oil Company *2 and the Civil Aviation Authority of the UK *3 stating that the fuel

should not be used above 20C due to the volatility being higher, and the chance of vapor lock

happening as well as carburetor icing, the symptoms of old fuel, and the fact that the fuel we

have in stock was received in June, we cannot use of the MOGAS we have in stock and a

different solution needs to be found.

The argument of financial savings for the company using MOGAS instead of using AVGAS

weighs heavily towards AVGAS. During the months of January until we started using the

MOGAS we never had an aircraft down or squawked for engine issues. Since we have started

using MOGAS and a mix of AVGAS and MOGAS we have lost a total of 99 flying days due to

aircraft on the ground. That is a loss of around 400 flight hours. The cost of 12 sparkplugs of

$29.83 each or, a total of around $358 and around 400 man hours due to the use of the MOGAS

and the loss of an aircraft reducing our fleet by 20% is not efficient and is actually very

expensive.

As the Chief Flight Instructor here at Flybest Flight Academy I cannot allow the use of MOGAS

fuel in our aircraft since it is an obvious risk to the safety of our students and instructors. The

fuel MOGAS may be usable to other climates with cooler temperatures and faster delivery

times but it cannot be done so here.

I hope you can understand why I have taken this position with regards to the use of the MOGAS fuel. I have the responsibility to the students, staff and company to prevent anything that has to do with safety from affecting the outcome of any flight or training the students will receive here at FlyBest. I do understand the concept of saving costs and being as efficient as possible. Sincerely, Denis R. Boissonneault Chief Flight Instructor FlyBest Flight Academy

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Appendix H