Modifying & Repairing Aircraft One of the main features of the LAA system is that modifications and repairs can be approved with significantly reduced costs compared with aircraft on Certificates of Airworthiness, where applicants would need to deal with the CAA or EASA. Since the engineering team are all ‘little aircraft’ experts, it is usually a straight-forward job to approve many types of change. Of course, with many of our members being so creative, sometimes the job takes a little more time and thought to approve! View current mod/repair application queue Modifcation Type Description Further Details Application Form Application Fee Category Changes Applications to change an aircraft’s category from a microlight to a ‘Group A’ aircraft (and vice versa) are allocated a modification number to record the change. If an engine or propeller change is required at the same time, then an application must be made as noted above. N/A LAA/ MOD 10 £206 Engine & Propeller Changes These are treated as Prototype or Repeat modifications, unless they appear on the PTL list for the type. Technical Leaflet TL 3.02 LAA/MOD 4 and LAA/MOD 5 * See below Avionics Installations These are not considered modifications, but in order to fulfil their legal obligations, owners are required to keep LAA up-to-date should radio details alter. A special system exists for the approval of radio changes that is separate from other modifications. Technical Leaflet TL 3.03 LAA/MOD 7 No charge for radio/transponder installations, but a £31 fee is chargeable for certified ADS-B Out applications STCs Where a change has previously been approved by means of a Supplemental Type Certificate (STC), LAA Engineering then only needs to investigate any installation/compatibility issues rather than the change itself. N/A LAA/MOD 13 £52 The Trivial Change Sometimes a change is so trivial that no application is required and there is no need to inform the Engineering department. Technical Leaflet TL 3.10 N/A N/A Manufacturers' Modifications Kit manufacturers and plans suppliers often have long lists of optional modifications that can be fitted and during the lifetime of a type product improvements are introduced. Generally, LAA-accepted optional items are listed on the TADS for the type. N/A N/A N/A The Standard Modification This is a modification that is very well defined and is applicable to a particular aircraft or engine type or types. Members may nominate new Standard Modifications using form LAA/MOD 9; however, LAA Engineering may choose to convert popular Repeat modifications into Standard Modifications. Technical Leaflet TL 3.06 LAA/MOD 1 Variable, see individual mods for details The Repeat Modification A modification that has already been approved on one aircraft as a Prototype modification. Note that a Repeat modification must identically replicate the original Prototype modification including fasteners and positions of parts and should generally be on the same aircraft type as the original. Technical Leaflet TL 3.07 and TL 3.17 LAA/MOD 11 * See below The Prototype ("normal") Modification This is a normal modification application made in the usual way and is applicable only to the aircraft for which the application is made. Technical Leaflet TL 3.01 LAA/MOD 2 and LAA/MOD3 * See below * All prototype modifications (including engine and propeller changes) attract a minimum fee of £103 which covers up to two hours' work; all repeat modifications (including engine and propeller changes) attract a minimum fee of £52 which covers up to one hour's work. Thereafter, work is charged at £57/hour in either case. See the relevant Technical Leaflet for the type of modification for further details. To access the Technical Leaflets, MOD forms and Standard Modifications described above, click one of the buttons below: Technical Leaflets on Modifications & Repairs LAA MOD Forms Standard Modifications

Lycoming Lycoming engines in certain specific airframe types have been approved by the CAA for the use of unleaded Mogas, using the process described in CAP747 , See Section 2, Part 4, General Concession 5. This involves purchasing an STC (Supplemental Type Certificate) from either the EAA or Petersen Aviation in the USA and carrying out the actions called for by the STC. The procedures stated in CAP747 may be followed for LAA aircraft but only for aircraft with the exact same engine/airframe combinations quoted on in CAP747.. An LAA inspector must check that the aircraft operator has obtained a copy of CAP747, Section 2, Part 4, GC5 and of the appropriate STC and complied with the actions called for therein, and signed off a suitable logbook entry accordingly before the aircraft may be flown with unleaded Mogas.

We provide a system whereby members can build an aircraft in the comfort of their own home (or wherever they choose) from either a set of plans or from a kit of parts. Every year around 100 newly-constructed aircraft are added to the LAA fleet, with members generally taking around 1 to 4 years to complete their kit projects. A whole range of aircraft is available to build, from single-seaters to four-seaters, aerobatic to amphibian, and WWI replica triplanes to gyroplanes. The LAA is tasked with ensuring that the designs members build meet minimum airworthiness requirements, appropriate to the type. Proposals for accepting other designs of aircraft can be put to the LAA, and a number of such types are accepted each year following a review of their airworthiness, amongst other things. This requires a member to champion the type through the process, arranging for the necessary technical information to be passed to the Engineering department and to build and test the first example. Similarly, it is possible for a member to build an aircraft of their own design. LAA provides support for this (see the Designing aircraft section), but due to limited resources only the most promising/developed designs can be advanced through the system. Building Aircraft One of the founding principles of the LAA is to provide for members wishing to build their own aircraft, either for their own education or to enable them to own an affordable aircraft. Of course, whichever type you choose it is usually possible to customise it to your liking using the LAA’s modification system. So if it’s an elaborate avionics suite that takes your fancy or an automotive engine conversion, there’s a route to investigating whether it’s possible. If you like the idea of building, but feel you lack the skills, then there are courses on various aspects of aircraft building to help bring you up to speed. Your Inspector is also a fantastic mine of information and generally will be your first port of call for technical information. Of course, the LAA also has a pool of full-time engineers who can be contacted for advice. For further information, click the button below for Technical Leaflets covering the Build Process Click here for more information

< Back LAA Alert for Rotax 900 series engines regarding the oil spray nozzle 18 Dec 2024 Inspection and/or Replacement of Oil Spray Nozzle On 16.12.24, Rotax issued a new MANDATORY Service Bulletin SB 912 i-016/SB 915 i-016 / SB 916 i-006 which calls for urgent action for engines of specified models within certain serial number ranges, if the engine has run for less than 200 hours from new, or engines which have been fitted with specific overhaul kits supplied between 01.01.22 and 31.10.24 inclusive. The bulletin concerns problems with a possible full or partial blockage of the oil spray nozzle due to an excessive application of Loctite at the manufacturing stage, when assembling the sprag clutch housing. This can lead to inadequate cooling of the stator assembly, potentially causing loss of electrical power to the engine’s ECU. A-05-2024 Rotax Engine Oil Spray Nozzle .pdf Download PDF • 205KB Next Previous

Ethanol-Free Mogas Please select the appropriate engine type link below where you will find information describing how to obtain clearance for an aircraft to use unleaded Mogas. For Rotax, Jabiru and VW engines, please see the E5 Mogas page. Continental Hirth 2 Stroke Lycoming Related Information Operating Information TL 2.20 Fuel Flow Checking Inspection Checks - Fuel Flow EASA Investigation on MOGAS EASA has issued the Final Report of the Safety Implications of Biofuels in Aviation (SIoBiA) This project was undertaken by the University of Aachen under a research contract to EASA. The Light Aircraft Association was represented during this project by Barr y Plumb, who was a member of the project steering committee. All aspects of t he use of Mogas containing biofuel additives were considered in the research programme and the final report from the project is now publicly available here . This is a summarised version of the SIoBia findings. Placards Cockpit Placard Fuel Filler Placard

Light Aviation Magazine 2020 Click on the links below to open each issue of Light Aviation Magazine from 2020 January 2020 April 2020 July 2020 October 2020 February 2020 May 2020 August 2020 November 2020 March 2020 June 2020 September 2020 December 2020

Light Aviation Magazine 2021 Click on the links below to open each issue of Light Aviation Magazine from 2021 January 2021 April 2021 July 2021 October 2021 February 2021 May 2021 August 2021 November 2021 March 2021 June 2021 September 2021 December 2021

< 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 Alert A-10-2025 - Cracking in E-Props Carbon Propeller Hubs 28 Aug 2025 LAA Alert A-10-2025 - Cracking in E-Props Carbon Propeller Hubs A recent report of a crack appearing on an E-Props carbon composite propeller hub was received by the British Microlight Aircraft Association (BMAA). The crack was in the flange forming the periphery of the circular hub, in the close vicinity of one of the bolts in the outer ring of blade clamping bolts. Alert A-10-2025 shows photographs of the crack discovered and details required actions if cracks are found on LAA aircraft. A-10-2025 is available HERE and shown below. A_10_2025_E_Props_Propeller_Hub_Cracking_Issue_1 .pdf Download PDF • 382KB Next Previous

< Back Engineering updates in April 6 May 2025 The following documents have been issued/updated in the Engineering 'Info Library' during April. Technical leaflets : TL 2.00 - Revalidating your aircraft's Permit to Fly TL 2.33 - Inspector categories for types (new TL) Forms: LAA/AR-REF - Airworthiness review reference guide (crib sheet) (new form) LAA/CFS-1 (fixed wing) - Check flight schedule LAA/PFRC-1 (fixed wing) - Permit flight release certificate Next Previous

< Back LAA Alert issued for Lycoming Engines 28 Nov 2024 The LAA has issued Alert A-02-2024 (link below) to highlight the recent Lycoming Airworthiness Directive regarding connecting rod bushings and connecting rod assemblies. The FAA has issued a new airworthiness directive (AD) for models of Lycoming engines that have an affected part installed and are assembled within the ship date range, as specified in Table 1 to paragraph (c) of this Airworthiness Directive (AD 2024-21-02). The AD comes into effect on 5th December 2024. This AD was prompted by several reports of connecting rod failures which resulted in uncontained engine failure and in-flight shutdowns. The AD requires repetitive oil inspections for bronze metal particulates at each oil change, and if found, additional inspections of the connecting rod bushings for damage, proper fit, movement, and wear, and replacement if necessary. The first oil inspection must take at the next oil change or within 4 months after the AD becomes effective i.e. 5th April 2025, whichever occurs first. As terminating action to the connecting rod bushing inspections, this AD requires replacement of the connecting rod bushings with parts eligible for installation. LAA A-02-2024 - Lycoming Connecting Rod Assemblies .pdf Download PDF • 203KB Next Previous

Night IFR PROCESS SUMMARY LIST OF TYPES PERMIT IFR FEES NIGHT IFR INSPECTORS FAQs POH LITE TEMPLATE (PowerPoint File) NIGHT IFR PILOTS ACCEPTED INSTRUMENTS TL 2.27 - PROCEDURE FOR APPROVAL & TL 2.28 - ASSESSMENT OF AIRCRAFT LAA/MOD15 APPLICATION FORM