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E10 Mogas From 1st September 2021, the government mandated that all regular grade unleaded petrol must contain up to 10% ethanol, rather than up to 5% as previously. In the autumn of 2021, most filling stations around the UK re-marked their E5 petrol pumps to show that they now supply E10 specification fuel, and started receiving tanker-loads blended with up to 10 percent ethanol content. For the automotive world this means reduced carbon dioxide emissions, which is better for the environment, and, arguably in terms of eco-desirability, a small further reduction in the reliance on fossil fuel. The automotive industry had been preparing for this change, and people with road vehicles registered after 2002 should be able to switch to E10 without noticing any difference. Unfortunately, the additional ethanol content is bad news for aviation users if we were to ignore the change and start putting E10 in our aircraft regardless. Ethanol is a powerful chemical solvent which can attack components including rubberised gaskets and fuel pipes, older lacquered carburettor floats and composite or plastic components in some newer fuel systems. The doubling of the concentration of ethanol in E10 compared to E5 makes it much more likely that problems will be experienced if these parts are not designed to be ethanol-proof. Ethanol also has an affinity for absorbing water, which over time can then become acidic, attacking metal components in the fuel system and engine. Even if there was a practical way to do so in the volumes of fuel we use in our aircraft, we cannot safely remove the ethanol content from the fuel because the ethanol acts as an octane enhancer, so the washed-out fuel would be left with a reduced octane value, likely to cause detonation problems. Another issue is that ethanol-blended fuel has a lower energy density than petrol, so to develop full power from our engines using an E10 fuel, we may need to richen the fuel/air mixture, for example using a bigger carburettor jet size. Owners of Rotax and Jabiru engines are probably already aware that many of these engines are supplied as being able to use E10 fuel – though with Jabiru engines, in particular, it’s far from straightforward because some of the earlier engines require cylinder head modifications and reduced compression ratio if they are to avoid detonation issues when using any form of Mogas. Jabiru also say that Mogas of any type should not be used in commercial flight schools and only at the owners own risk. Even with a supposedly E10-compatable engine, the chemical compatibility problems with fuel system components are such that the LAA does not at present approve the use of E10 Mogas in any LAA amateur-built or vintage aircraft. For factory-built microlights and factory-built gyroplanes, where LAA is not the approving authority but only renews the CAA’s Permits to Fly, owners need to refer to the TADS for the types for details of the approved fuel types, and monitor the service bulletins from the approved manufacturers for news of any updates. Where we need to be particularly careful in reading-across from (hopefully) a trouble-free transition to E10 in automotive use is the big difference between our petrol cars and the way our aircraft engines are configured. Our cars generally have submerged fuel pumps in their petrol tanks and a sealed fuel system. In our aircraft we have an open-vented tank and usually a fuel pump several feet away, often mounted in a hot area of the engine bay near to the engine exhaust, dragging the fuel through a fairly convoluted pipework system, a filter and fuel selector – all features encouraging a vapour lock - and then to make matters worse we want to climb up to altitude and operate in reduced atmospheric pressure. Modern petrol cars have a fuel injection systems rather than carburettors, a circulating fuel system designed to purge any vapour forming in the fuel line, and an ECU that monitors the engine’s parameters constantly and adjusts the fuel mixture strength and ignition timing to prevent damage to the engine – and if all else fails and the engine should ‘pink’, we can hear it from the driver’s seat and drop a gear to lighten the load. Because of the much higher background noise level in our aircraft, detonation cannot be heard and the pilot’s first indication of a problem may be when the first piston crown disintegrates, or a valve head departs its stem. In conclusion - E10 is presently not approved for use in any LAA aircraft. ‘Hoping for the best’ and using E10 fuel in your aircraft regardless could risk ruining the fuel system components, fibreglass tanks falling to bits, engine failure through contamination of the fuel or ruptured fuel pump diaphragms etc, or more serious engine damage. For most of our engines, UL91 Avgas is the best choice, but 97 octane E5 Super Unleaded remains an alternative to the now-obsolete E5 spec Mogas.

Continuing Airworthiness Information One of the key strengths of the LAA's system is that we can monitor the fleet centrally and keep track of airworthiness incidents from around the world. Where necessary, we can then let our owners know, to help them keep flying safely. A full listing of Airworthiness Alerts, Technical Service Bulletins and Mandatory Technical Directives can be found below: ALERTS, TECHNICAL SERVICE BULLETINS & MANDATORY TECHNICAL DIRECTIVES

< Back LAA Alert for some models of Rotax Engines 1 Mar 2025 LAA Alert A-02-2025 has been published on the LAA website (and is also attached), highlighting a recent service bulletin published by Rotax regarding the inspection and/or replacement of the crankcase and/or gearbox housing on affected engines. Rotax has identified a potential manufacturing issue affecting the hardness values of the crankcase and/or gearbox housing materials in certain engines. These components may not meet the required specifications for material hardness, which could lead to reduced component durability and/or potential oil leakage. Rotax regards this bulletin as mandatory. A-02-2025 - Rotax Crankcase .pdf Download PDF • 220KB Next Previous

Light Aviation Magazine 2023 Click on the links below to open each issue of Light Aviation Magazine from 2023 January 2023 April 2023 July 2023 October 2023 February 2023 May 2023 August 2023 November 2023 March 2023 June 2023 September 2023 December 2023

Light Aviation Magazine 2016 Click on the links below to open each issue of Light Aviation Magazine from 2016 January 2016 April 2016 July 2016 October 2016 February 2016 May 2016 August 2016 November 2016 March 2016 June 2016 September 2016 December 2016

Over the years this has led to several commercially successful kitplanes (Europa, Streak Shadow, Sherwood Ranger), as well as designs that have been released for plans-building (Flitzer, Isaacs Fury, FRED) and a whole range of fascinating on-off personal aircraft – the Acro Advanced, Bonsall Mustang, Mickleburgh Sparrow to name just a few. There will always be LAA’ers keen on the ‘retro’ look, but with ever-increasing fuel costs we foresee a greater emphasis in future on aircraft exploring higher efficiency, alternative powerplants (electric?) and renewable materials. High hangarage fees mean that aircraft enthusiasts are more than ever interested in folding or de-riggable aircraft that can be kept at home. Using the information provided by clicking the links below, the LAA hopes to stimulate interest in light aircraft design, help potential designers through the process and encourage the development of high quality designs. With the decline in UK manufacturing over the recent decades, it seems more than ever important to keep alive a thread of creativity and enthusiasm for design and development. For some, the ability to bring a personal design from first concept to a flying prototype provides the ultimate source of satisfaction within the LAA scene. Designing Aircraft Since its formation in 1948, one of the stated aims of the LAA has been to encourage the designing and building of new types of light aircraft. For our own purposes, we in LAA Engineering have been producing a series of Excel spreadsheets to use as tools in the verification of calculations in the many aircraft design submissions we deal with. The spreadsheets have been designed to carry out the various calculations that are necessary during the design of light aircraft. Some of them have been written against specific paragraphs in the design code CS-VLA, whereas others, for example, cover areas related to the development of aircraft undergoing flight testing. In addition, simple spreadsheets for straightforward mathematical calculations have been written. It is for information and educational purposes that these spreadsheets are now available to LAA members on the LAA web site. Use the buttons below for more information on each design stage: Preliminary Design Detail Design Certification/Approval

< Back Grass Roots Fly-In Slots and Tickets now available! 26 Jul 2023 Not long to go now!! Details on slot bookings, entrance tickets, camping, exhibitor information, trophies and awards, opening times, other attractions etc are now available Fly-in details can be found here . Next Previous

< Back New LAA Inspector - Tom Bootyman 20 Jun 2024 We are pleased to welcome Tom Bootyman as an LAA Inspector. Tom attended an Assessment Day at LAA HQ at the start of June. Tom is a serial aircraft builder/maintainer/repairer, also with several years’ experience as an engineer with a global aerobatic team. He has experience building and repairing Zenair and Vans RV types, along with working on many aerobatic aircraft. He is also an experienced aircraft painter. Tom has a love and devotion to all things aviation, so he is always open to requests for information, advice and Permit inspections. He is based at Netherthorpe (Sheffield), but willing to travel. Next Previous

< Back Engineering updates in October 11 Nov 2025 The following documents have been issued/updated in the Engineering 'Info Library' during October. Continuing airworthiness information : Alert A-11-2025 - Eurostar control system rose joints Alert A-12-2025 - Aeroprakt windscreens TADS: Evektor Eurostar Vans RV-9/-9A Propeller type lists PTL/1 : Murphy Renegade 912 (new) Murphy Renegade Spirit (new) Vans RV-6 (up-issued) Next Previous

< Back New LAA Inspector - Andrew Williams 31 Mar 2025 We are pleased to welcome Andrew Williams as a new LAA Inspector, having attended an LAA Inspector Assessment Day at Turweston recently. Andrew has been involved with aircraft maintenance for approximately 36 years. Types he has worked on include Rolls-Royce Dart and Pratt & Whitney PT6-powered passenger and freighter aircraft, followed by working on short-to-medium range jet aircraft. For the last 10 years, Andrew has been involved with general aviation single and twin-engined aircraft, carrying out maintenance and certification. He holds a CAA approval to perform Airworthiness Reviews in order to issue Airworthiness Review Certificates. His qualifications include: CAA Part 66 Licence, inc. Full Group 3 and a BCAR Sec L Licence. In the LAA ‘world,’ Andrew has a share in a Jodel 1050. Congratulations Andrew. Welcome to the team! Next Previous

< Back New LAA Inspector - Ben Davis 27 Nov 2025 We are pleased to welcome Ben Davis as a new LAA Inspector, having attended an LAA Inspector Assessment Day at Turweston recently. Ben has been an aircraft owner for about twenty years and has become something of a fan of the (mighty) Alpi Pioneer series. He’s owned several and flown several more. Ben has also refurbished and upgraded a number of Pioneers with new avionics, autopilots, and instruments. Along the way, he has owned and improved a Europa and a few other types, but he always seems to find his way back to a Pioneer! Ben also enjoys staring out of the front window of little biz jets. With a background in electronics, moving into avionics was a natural step for him. Ben is a Rotax iRMT (Line & Heavy), a BMAA Inspector, and now also an LAA Inspector, combining his technical background with years of hands-on experience. Ben is based at Finmere, just a short hop from LAA HQ, and is always happy to help other owners with maintenance, upgrades, or just a good aviation chat. You can find him sharing projects and flying adventures on social media as @benfly79. Next Previous