97 Octane Super Unleaded Since the replacement of regular E5 Mogas at the pumps by E10, for the time being at least, Mogas users have an alternative option in the form of 97 RON Super Unleaded fuels. 97 RON Super Unleaded fuel supplied by garage forecourts is NOT necessarily ethanol-free, but its ethanol content will be capped at a maximum of 5%. 97 RON E5 Super Unleaded fuel can be used under the LAA process for E5 Mogas, as before. There’s currently no legal requirement for ethanol to be present in super unleaded petrol and in fact, quite a few members have reported that their tests have shown Super Unleaded fuel to be ethanol-free in their areas. Esso reports that “Synergy Supreme+ 99 is actually ethanol free (except, due to technical supply reasons, in Devon, Cornwall, North Wales, North England and Scotland). Legislation requires us to place E5 labels on pumps that dispense unleaded petrol with ‘up to 5% ethanol’, including those that contain no ethanol, which is why we display them on our Synergy Supreme+ 99 pumps”. Shell, BP, Tesco and other fuel suppliers don’t commit to such detail, merely stating their fuels “may contain up to 5% ethanol”. Of course, many LAA members have been using Mogas of one sort or another for many years. For many airstrip users, the prospect of having to go to an airfield to fill up with Avgas would seem at best very off-putting, and at worst totally impractical for their style of operation. Hopefully Super Unleaded will continue to be an option using the LAA’s E5 procedure. Where 97 octane E5 super unleaded can be found that’s ethanol-free, it can be used in the broader range of LAA aircraft with engines eligible for use with E0 unleaded fuel. But it is important that Mogas users take on board the fact that unlike with aviation fuels, automotive fuel specifications generally only describe the properties of the fuel blend, in terms of octane rating and other characteristics, they don’t specify the chemical make-up of the fuel. Apart from specifying broad maxima and minima for those components that the powers-that-be wish to either encourage or discourage, the specifications leave to the fuel supplier the choice of how to blend the fuel to achieve the described properties. In some cases it’s the relatively small amounts of additives that cause compatibility issues, rather than the main components of the fuel that cause the problems – and the mix of additives may vary from one batch to the next. With Mogas of any type, what you get from the pump one week may be different to what you get the week after, or got the week before. The fact that your fuel system pump diaphragms, seals, composite tanks and so on might have been unaffected by Mogas up till now does not guarantee that they will be OK with the blend that the next tanker-load brings to your garage forecourt. Unfortunately there is no simple answer to this, and the only way to mitigate this problem is by constant vigilance, and thoughtful adaption of your maintenance schedule to check for signs of problems developing before they create a safety issue – more frequent checking of filters, changing of fuel lines etc. Signs to watch out for are swelling of rubber components like diaphragms, fuel valve seals and O rings, fuel pipes hardening or developing surface cracks, fuel tank sealants wrinkling or detaching from the internal surfaces of fuel tanks. Varnishes on cork floats may go gummy, or plastic carburettor floats absorb fuel and lose buoyancy, causing a rich mixture and rough running. Watch out for discolouration of the fuel you take out as fuel samples, which may imply something dissolving somewhere in the system, and for corrosion in the bases of your carb float bowls and gascolator. Avoid letting Mogas go stale in your fuel system – drain it out before a long period of disuse. Don’t leave the tanks empty for a long period – better to fill them with Avgas which will reduce condensation, and also, particularly with plastic tanks, prevent the tank’s internals drying out which can cause problems with shrinkage, and in extreme cases, the tanks splitting open. O rings and other rubber parts are best kept submerged in fuel continuously. We’ve seen cases where composite aircraft skins have rippled apparently due to exposure to the vapours created by the break-down products in stale Mogas, after being left unattended over a single winter. Mogas is blended with the expectation that in a car it will be used within a few weeks of being supplied, so it doesn’t need to be as stable over a long period of time as an aviation fuel. If a composite or plastic fuel tank is built into your aircraft, consider carefully whether you want to run the risk of having to replace it should the tank deteriorate with Mogas exposure, with all that that implies. With an integral tank in a wet-wing Jabiru aircraft, the answer should be certainly not – but even with the embedded polyethylene fuel tank in a Europa’s fuselage, changing the fuel tank is not an operation for the faint-hearted, involving cutting out quite large parts of the fibreglass cockpit module to release the tank, and then scarfing them back again afterwards in-situ. The Europa kit was first produced in the era of four-star Mogas, a very different blend to what we find at the pumps today. Ethanol-proof rubber hoses are available. In particular SAE J30/R9 or the European equivalent DIN 7339 D3 are automotive hose standards that are widely available from auto factors, and should be used in preference to the older SAEJ30/R6 standard hose which is more permeable to fuel vapour and will more quickly harden and crack, particularly using fuel containing ethanol. The SAE spec J30/R14 is a lower pressure, more pliable version for carburettor systems. Watch out for cheap imitations – the real McCoy should come from a reputable manufacturer, be marked with the SAE number along its length and will likely cost at least £10 a metre. What can we do to help the situation ? It may be that off-the-shelf drop-in-the-tank additives can be used to mitigate some of the problems with mogas fuel, in particular, stabilisers and anti-corrosion products, just as they are routinely in the marine and race-car world. Not knowing what’s in them, we recommending steering clear of any additives that claim to boost the fuel’s octane. Definitely avoid additives that claim to actively enhance an engine’s power or fuel economy, other than just to restore proper performance by giving the carburettor jets and orifices an occasional clean-up. For most aircraft engines UL91 Avgas remains the ideal fuel, in that it is a tightly-controlled aviation-grade fuel of a guaranteed composition, blended for long-term stability and optimal volatility for aviation use. As it is in effect the familiar 100LL Avgas but supplied without its tetraethyl lead, any fuel system designed for 100LL Avgas will be unaffected by using UL91 fuel, or, if circumstances demand, by a mix of 100LL and UL91. Despite a pervasive mis-conception, UL91 fuel is NOT Mogas and suffers from none of the issues associated with Mogas use in aircraft. A list of engines suitable for use with UL91 fuel can be downloaded from the ‘operating and maintaining an LAA Aircraft’ page of the LAA’s new website. Moves are afoot to increase the number of airfields supplying UL91 fuel, with full LAA backing.

< Back MTD-04-2025 upissued to Issue 2 - Rans Control Linkage Rod End Connector Safety Washers 18 Nov 2025 MTD-04-2025 Issue 2 - Rans Control Linkage Rod End Connector Safety Washers MTD-04-2025 Issue 1 was recently published to mandate the replacement of all plastic control linkage rod end connector washers with metal washers . It has become apparent that the washers specified in this MTD are not suitable to replace the plastic washers due to their dimensions. MTD-04-2025 Issue 2 has been raised in order to amend the specification of the metal washers that must used to replace plastic washers. Therefore, MTD-04-2025 Issue 2 supersedes Issue 1. Issue 1 of this MTD is now cancelled. Please refer to the attached MTD document for full details and compliance instructions, which can also be found on the LAA website HERE . MTD-04-2025 - Rans Rod End Washers - Issue 2 .pdf Download PDF • 293KB Next Previous

< Back Replica De Havilland DH71 Tiger Moth Racer takes to the air 23 Dec 2024 Steve Jones’ replica DH71 Tiger Moth Racer made a highly successful maiden flight on 26th November, piloted by Steve himself. The immaculate monoplane, appropriately registered G-ECDX, is a full-size recreation of one of only two examples built by de Havilland in 1927. Of all wood construction, and fitted with a modified DH Gipsy 1 engine, the original DH71s were created to publicise their new Gipsy engine before releasing it onto the market to power their already successful DH60 Moth biplane. An exercise in light weight and streamlining to maximise speed, the DH71 was also significant in developing construction techniques that de Havilland used to good effect in later designs. The original DH71 achieved 186mph around a 65 mile closed circuit course, its Gipsy 1 engine souped-up from 85 to 130 horsepower for racing. The replica project was largely built by Ron Souch in the 1990s, under PFA supervision, using drawings produced by Ron’s friend Ben Price, a former aircraft draughtsman who put forward the idea as his retirement project. None of the original construction drawings had survived, so the design had to be recreated based on a three-view, photographs, press articles and intimate knowledge of de Havilland’s standard design techniques – and then checked against modern design code requirements. Most challenging part of the design were the details of the internally bungee-sprung wheels, as on the original. The project was paused for several years after issues came to light with the stressing of the wing spars and undercarriage. Steve Jones, looking for a hangar-mate for his scratch-built Comper Swift project, purchased the DH71 in 2016. Steve quickly got things moving again by commissioning re-designs of some of the original components, stripping off the fabric covering, re-sparring the wings and finishing the aircraft off to the same high standard as its original construction. The final examination of the assembled aircraft by LAA HQ’s design staff in November, when ground runs of the modified engine and its very coarse pitch Hercules propeller were demonstrated, took place over three decades after the project’s inception. When Steve’s replica DH71 first lifted off from Sywell’s grass runway, it was a sight not seen in Britain for 95 years. Big congratulations to all involved, especially to Ron and Ben for initiating it, and Steve’s perseverance and skill in finishing all the last details to such a high standard. Honourable mentions also to John Tempest for the re-design work and Ben Cox for inspecting it, this was truly a team effort. Sadly, Ron Souch is no longer with us to see the Racer fly. https://video.wixstatic.com/video/62c8d3_cf3ab2cf7a524a2d953fd5a8f08ed411/480p/mp4/file.mp4 Steve describes his aircraft experience as starting as an aircraft engineering apprentice at CSE Kidlington, in the late 1970s. He towed gliders at Husbands Bosworth, in Chipmunks, at age 19, and joined the Tiger Club in the late 1970s, becoming a flying instructor at Staverton 1981. As he describes it, he somehow (?) ended up flying BA 747s for 20 plus years. His remarkable flying career has involved air racing, aerobatic competition and display flying, Redbull competitions and record setting in the Rolls Royce electric powered ‘Spirit of Innovation’ aircraft. Next Previous

< Back MTD-05-2025 Issue 2 published - Eurofox Rudder Pedals 5 Dec 2025 MTD-05-2025 Issue 2 has been published to provide further information on the situation as it develops and asking Owners and Inspectors to report back. The inspection schedule in unchanged from Issue 1. Therefore, Issue 2 does not require you or your Inspector to do anything different. If your aircraft has already been inspected to MTD-05-2025 Issue 1, then the next time an inspection in accordance with the MTD is due, you Inspector should reference Issue 2 in their logbook entry. LAA is continuing to work towards achieving a permanent solution via a modification to the rudder pedal/torque tube design. MTD-05-2025 Issue 2 is attached below and can be found on the website HERE . MTD-05-2025 - Eurofox Rudder Pedal Cracking Issue 2 .pdf Download PDF • 574KB Next Previous

< Back LAA host British Young Pilots 19 Feb 2026 The LAA is happy to support British Young Pilot's Weekend Club at LAA HQ, Turweston Aerodrome. More details about these events can be found below: BYP .png Download PNG • 2.87MB Weekend Club Turweston .pdf Download PDF • 688KB Next Previous

< Back Engineering updates in December 2 Jan 2025 The following documents have been issued/updated in the Engineering 'Info Library' during December. Continuing airworthiness information: Mandatory Technical Directive 07-2024 - Eurofox trim cables Alert 03-2024 - Eurostar trim cables Alert 04-2024 - Loose Rotax engines Alert 05-2024 - Rotax 900 series engines - blocked oil spray nozzle Technical Leaflets: TL 2.22 'non-type specific MPDs' TADS : Sling 4 TSi Wishing all our members a very Happy New Year. Next Previous

< Back Alert A-09-2025 - Hairline Cracking in Woodcomp Klassic Propeller Blades 19 Aug 2025 Alert A-09-2025 - Hairline Cracking in Woodcomp Klassic Propeller Blades LAA Alert A-09-2025 has been published on the LAA website (and is also attached), highlighting reports of Woodcomp Klassic blades found with hairline cracks in the blade’s surfaces, running chordwise, usually outboard of about 30% radius. The Alert described actions for Owners to take if such cracks are found and to contact LAA Engineering. A-09-2025 - Woodcomp Klassic Propeller Blades issue 1 .pdf Download PDF • 205KB Next Previous

< Back LAA Open Day - Saturday 1st June 2024 9 May 2024 Flying in? PPR is needed. Contact: [email protected] Browse through our Flea Market table Meet LAA staff and Board Members Talk by Lucy Wootton our Chief Inspector on "How I got into flying" Instructors available to answer any questions you may have Browse through our retail shop for LAA merchandise, including charts, log books and clothing. A selection of LAA magazines available for free! Tea and coffee served in our members area and also a catering van will be available on-site for food and refreshments,. Next Previous

< Back The New Permit Revalidation System - Step-by-Step Guide 9 Apr 2025 The new LAA Permit to Fly revalidation system will go live on 15th April 2025. This streamlined, fully online process offers an easier and faster way for aircraft Owners and Inspectors to handle Permit to Fly revalidations. Watch this video for a step-by-step guide on how to complete the online Permit Revalidation process, both as an Owner and as an Inspector. https://www.youtube.com/watch?v=rOGRQ89dOA8 There are a few key considerations to ensure your revalidation under the new system goes smoothly: Please make sure you know your username and password before applying for your aircraft’s revalidation. If you have forgotten your login details, please contact the LAA Office. All aircraft using the new system for the first time will require a check flight no older than 3 months at the time you submit the revalidation application. This is in order to provide a baseline for the online system. The 3-year check flight schedule will then apply subsequently to most aircraft types. Some aircraft will still require a check flight at every revalidation, these are: Aircraft cleared for glider tugging in their Operating Limitations document. Aircraft cleared for Night/IFR. Aircraft which have flown less than 12 hours since the previous revalidation inspection. You will not have to submit your CFS-1 Check Flight Schedule when applying through the new system. However, a CFS-1 will need to be completed for each check flight and stored with the aircraft’s documentation, so that it is available when needed. We encourage you submit your revalidation application through the new online system, as processing time is expected to be faster than an ‘old-style’ revalidation. If you still wish to make an ‘old-style’ application up until 15th May 2025, all 3 forms must be submitted by this date and you will only transition to the 3-year check flight schedule after your first revalidation through the new system. Note: The option to apply for revalidation in ‘My Aircraft Data’ on the LAA website may appear shortly before the go-live date on 15th April 2025 as our IT infrastructure is updated. However, we will only be able to process applications received on or after the official go-live date. A handy list of 'Frequently Asked Questions' is available below: 20240409 - Permit Revalidation Process FAQs V1.0 .pdf Download PDF • 175KB 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

< Back MTD-04-2025 Issue 3 - Rans Control Linkage Rod End Connector Safety Washers 4 Dec 2025 MTD-04-2025 upissued to Issue 3 to amend the specification of the metal washers that must used to replace plastic washers. MTD-04-2025 Issue 3 is published in order to amend the specification of the metal washers that must be used to replace plastic washers. Therefore, MTD-04-2025 Issue 3 supersedes Issue 1 and 2. Issue 1 and 2 of this MTD are now cancelled. Please refer to the attached MTD document for full details and compliance instructions, which can also be found on the LAA website HERE . MTD-04-2025 - Rans Rod End Washers - Issue 3 .pdf Download PDF • 130KB Next Previous

< Back AGM The awards ceremony will start at 11.30 a.m. Registration for entry into the AGM will be open at 10.45. For more details, please see link below. https://www.lightaircraftassociation.co.uk/agm2025 Next Previous