Modifications

By Ian Rickard

When I started building my Europa the area that I found most confusing was the whole issue of modifications. So, for all those building in the UK (LAA rules OK), I will try and tell you what I have learnt. I apologise to our non-UK readers who can pass on to areas of greater interest or stay to gloat or sympathise as their situation dictates.

I think the first thing you need to be aware of is that the FACTORY is selling a kit and YOU are building an aircraft to fly under licence from the LAA. These two statements are not synonymous. As you will be aware, the factory does not provide everything to complete the aircraft. The factory is very interested in improving its product and has produced a series of useful modifications, and will continue to do so in future as resources permit. Due to its resources being fully committed, the factory does not become involved in individual modifications.

As a new builder, you study every brochure, Internet site and any aeroplane you can get your eyes (or hands) on. You soon noticed that many contained equipment and modifications that are highly desirable. It also becomes apparent that some of these are quite fundamental and need to be done as part of the initial construction of the aircraft. Even those that could be done retrospectively cry out to be done during the initial build to save the duplication of effort. So, you start looking for information and asking questions.

What you learn from everybody is that these are all modifications (mods) that are subject to LAA approval. The factory cannot help; the LAA cannot help at the present time (despite what the article in Popular Flying says) and the story you hear from other builders is very confusing. If you get the information pack on mods from the LAA, you realise it must have records of all the modifications of which it has been notified. They even ask you to list other aircraft that have that modification, information they possess but which is inaccessible to you. All this is very frustrating. What you really want is access to a list and description of all mods that is as complete as possible. This, with some guidance that the LAA, the Club and other builders can give, would allow you plan your build logically. I will come back to the subject of information at the end of this article.

So what is a mod? The simple and correct answer is that it is anything that you do not build exactly as per the manual AND your inspector says (or insists after you have tried to convince him otherwise) is a mod. In particular, mods are any changes that may affect the structural or aerodynamic properties of the aircraft. The objective of the LAA mods procedure is to allow these to take place in a way that ensures the continued safety of the aircraft (and you).

First, let us start with what is not a modification. In all examples, I will assume that what has been done is “engineered” to the best of your skill and ability.

You build some part not quite by the manual but use some clever improvement you saw on the Internet. Well, if your local inspector is happy to accept it, it is not a mod. If your inspector is not happy, then it is a mod. Your inspector is there to bring his/her knowledge and experience to your build (you and I do not want to fly in anything his/her “nose” says is unsafe). Two examples of this are:
1. the “Top Hat” method of installing the rear and mass balance bulkheads developed by Graham Singleton, and
2. the added flange on the engine cowling developed by the factory.
Both are much easier and stronger than the original. Many items in the Europa price list fall in this category such (e.g. Door locks, F23 moulding, comm. antenna kit, vacuum pump).
If an item is included in the “Component Record Data Sheets” (at the back of your LAA build logbook) you are, in general, free to choose what you use. The CRDS’s covers items such as an oil temperature or pressure gauge, RPM indicator, altimeter, ASI, compass, generator or battery. All you have to do is record it in your LAA build logbook. You must ensure that your inspector is happy, as some changes such as a digital, rather than analogue, altimeter could be seen as a mod. One area to watch out for is engines and propellers. There is a list of the combinations of engines and propellers that are acceptable to the LAA but which is not held by your local inspector. This is an area where we hope we can obtain and publish the information from the LAA. Any engine propeller combination not on the list would be a modification and probably involve you in extensive testing.

So now let’s get on to mods and start with the easy ones:

You add a factory-supplied mod. No problem - as long as your inspector is happy. It is a mod and all you have to do is record the mod number in your LAA build logbook. Europa has some sixty mods listed but most cover upgrading early kits to today’s standards. The only three Europa mods of interest to you, as a new kit builder, are a) Number 33 fuel drains, b) Number 53 long range tank, c) Number 56 speed kit. You will be pleased to hear that two more factory mods are being developed for a) stall warning system and b) hand operated brakes. You will find the available mods listed in the Europa News pricelist.
You add a Europa Club supplied mod. No problem - as long as your inspector is happy. It is a mod and all you have to do is record the mod number in your LAA build logbook. The Club has seven approved mods at present a) capacitance fuel gauge, b) engine cowl fasteners, c) over voltage crowbar unit d) instrument panel, e) seat locker doors, f) autopilot and g) strobe (fin mounted). You will find these mods listed on the Europa Club website. A mod for the outrigger pivot for the Mono is nearing completion.

From here on, life starts to get a bit more complicated you want to add something not specified in the manual, let say a fuel gauge.

If the fuel gauge is sourced from the UK, it should come with documentation on how to install it. This, with little effort, can be submitted to the LAA as a mod. This will obtain approval without comment or complications (despite involving a structural change) but is, in general, a waste of LAA time when it could have been cleared under a procedure similar to a Factory or Club mod. We will ask the LAA about improving this situation.
You want to fit the same fuel gauge but sourced from the US on cost grounds. This will come without documentation. You will, therefore, need to describe exactly how you intend to install the device in your mod application to the LAA. The work involved in doing this will depend on what is involved. In this example of a fuel gauge, it probably involves cutting a hole in the structure above the tank. This could be deemed a major structural change and a “letter of no technical objection” (LONTO) may be required. We will come on to LONTOs in a minute.
At last, we come to the most complex mods with obvious structural or aerodynamic implications. These include the centre tunnel (structural) and creating a tail-dragger (structure, aerodynamics, handling). These really must be treated with the respect they deserve. You will need to submit a mods application to the LAA and this will need to be accompanied by a LONTO from the structural designer of the Europa. In providing this letter he will carry out a structural analysis to ensure that what you propose is safe. This service is provided at a cost varying with the amount of work involved (from £125 to £600). You will minimise the cost of this service by providing the best possible drawings and description of what you propose. In cases such as the tail-dragger or a new engine, the LAA may require you to undertake extensive testing before a Permit to Fly is issued.

At the present time, these complex mods are processed for individual aircraft by the LAA. The club would like to see the most popular mods, such as the centre tunnel of a TriGear, cleared under a procedure similar to a Factory or Club mod. We will ask the LAA about improving this situation.

This leaves us with what I usually call “Un Mods”. You add something minor; let us say tie downs or tip lights to the wings. There could be structural implications but they are very minor if you have used your common sense (or engineering knowledge). Common sense dictates that this obviously is a mod. Unfortunately (or fortunately depending on your point of view), some inspectors treat them as items falling in my category a) above, as not a mod. This is to help, you as the builder, avoid the work and delays with the LAA mods procedure. Unfortunately, it means the LAA has no record of these mods and what it does have is not consistent, due to different inspectors’ interpretation of what is a mod. Equally, builders tend not to talk about them to protect their inspector. This is unfortunate, as some are superb examples of the thought, effort and skill builders have put into their aircraft. You will find some reference to many of these on the e-group and Internet sites.

Finally on this topic, beware of conflicting mods. Cutting a hole in one side of something may be acceptable due to the strength of the other side. Cutting a hole in the opposite side could be justified in a mod application to the LAA on the same basis. Cutting both could be very dangerous.

Your common sense and your local inspector is your best line of defence against this. The next question is what are we doing about it? We want to determine what are the most popular or desirable mods. To achieve this we need to undertake a survey of who has done what and, to some extent, how they did it. We need information from you as a builder, the LAA who have the details in their files, and the factory. We can then make the information available to builders, including on this Web Site.

We will probably separate the information into:

No Modification. So you know what should be OK with your local inspector (e.g. panel mods, baggage area tie downs, etc.).
Widely Used Mods - needing individual approval (e.g. fuel gauges, gascolators, strobes)
Ambitious Mods (e.g. tunnel mods, wingtip mods, autopilot)
Do not attempt if of sound mind (e.g. conventional tail-dragger, ballistic parachute)

[Web Site Editor's note: for the purpose of categorising mods on this site, all mods will be given a 'Rickard Rating' of difficulty as above - No Mod, Simple Mod, Ambitious Mod, or Extreme Mod]

Mods will also be grouped according to their source:

Factory mods
Club mods
Individual mods

We can then work towards removing the need for a mod application (with the associated implications in terms of effort, delay and cost) by:

Approaching the factory - are there mods which they can and will produce or adopt?
Approaching the LAA - requesting that popular modes become club mods given they are documented to ensure consistency

We would like to work towards a situation where all widely used mods are treated like club and factory mods and not on an individual aircraft basis. By using a documented design the need for LAA input would be reduced with a considerable saving in cost and time both to the LAA and the builder. Where the factory feels it is appropriate they may wish to own these mods or they could be documented by and become the property of the Europa Club.

On the problem of Un Mods, I believe this problem will disappear by classifying appropriate items as no modification and documenting others (e.g. cable ducts in wings) as club, factory or individual.