Light Aircraft Association

Does anyone know how I can access to or obtain information on Modifications approved for previous aircraft?

I'm tempted to just chainsaw my KR2 project and sell off the valuable bits due to wholesale unclarity on the required Modifications.

I don't particularly want to modify my aeroplane, and I don't want anything fancy - I just want to build it once, build it right, and get a Permit to Fly at the end.

Various people (existing UK KR2 owners, LAA Engineering) have told me that the original Rand Robinson drawings are unacceptable to build from, and that various modifications need to be incorporated. Sandy Hutton supplied me with a series of sketches of modifications drawn by Mike Whittaker, along with a narrative on the KR2 by Francis D.

Some of the sketches are labelled "KR2/KR2S" (the KR2S being bigger and heavier) and others are labelled "KR2S". After a conversation with Francis about whether or not the "KR2S" mods should apply to my KR2, the outcome was that if I wanted to fly at KR2S AUW I would need them, which I couldn't due to KR2 CofG and the outcome was thus a "No".
It would seem logical that the "KR2/KR2S" sketches would apply as they cover issues such as seat harness mounts and the likes...

The narrative, amongst other things, states a minimum foam density and prescribes 9oz/sq.yd bidirectional glass cloth in lieu of the "Dynel" cloth in the plans.

I have also been advised that the fabric sling seat shown in the plans is unacceptable, and needs to be replaced with something else. I know what is generally done to rectify this by most builders, but I don't know where to obtain a previously approved design to copy.

There are no mentions of the KR2/KR2S in the list of "Standard Modifications" on the LAA site, and again no mention in the "Incorporating a Modification Approved for all Type". My father (an inspector) has searched for relevant mandatory mods and again found no reference to the KR2.

To sum up, I know I need to deviate from the plans and build manual, and I know what I've been told to do. Paperwork wise though - I am lost. Some of these are most definately Major Modifications, and I don't want to spend thousands paying an Engineer to substantiate a suite of Mod Proposals which would appear to have already been done, yet are not on any lists of approved mods.

I genuinely don't have a clue what to do from here. I know what needs to be done on the aeroplane - that's fine and I don't have an issue with that. I just done want to (read "would abandon the project") pay a fortune to have all these Mod applications fleshed out by someone who knows what they're doing, and I don't want to submit a stack of forms and a cheque for £200odd with each form saying "As per Mike Whittaker sketch MW4" or "As per paragraph 2 line 5 of some article Francis Donalson wrote" - which would (quite rightly) go nowhere.

Surely if a modification is prescribed (and they are - they say "Use X material instead of Y", not "Area Z needs some improvement which you will need to design") then it shouldn't need to be submitted as a new Mod with all the backup? If it needs a form and the fee paid then that's one thing but I'd have thought that it was just a formality referencing something already documented at LAA Engineering? Are these Mike Whittaker sketches actually approved as Mods? If so, why aren't they on the afore mentioned lists? Do I just write my name and reg number on the Mod Application and staple the sketch to the back?

There have been some great guides to modifications written in the magazine recently, but they are aimed at new mods desired by the builder and describe the process from scratch. I don't honestly think my project fits that category - as far as I can see I'm trying to include phantom Standard Modifications?

Can anyone offer any advice? My father is as lost as I am. I wish I'd never bothered

I hope this doesn't come across as another anti-LAA Engineering rant - it isn't. Everyone's very busy and no-one there can be expected to know all these types inside out. I just want to be sure that I build an aeroplane, not an ornament.

Thanks Everyone,

Jamie

Jamie,
From the number of completed projects, there must be several other KR2 builders who've already jumped through these hoops. Isn't there a builders / owners network to collate these resources?

Hello Mike,

There is indeed a builders' network, but it is international with very few UK builders who regularly look in. In fact, I know only of Ken Atkinson from NW England who's been on there who definately built his own KR2.

Pete Diffey is on both here and the builders' network, but I'm unsure whether he built his or not. Likewise, Phil Brookman is on there but I know he bought his already completed

A builder who's already been over this would be fantastic - so if anyone knows someone in the UK who built one, please shout!

Guy in my hanger cut up his KR2 and junked the airframe - just selling the engine. Sad sight.

I may well end up doing the same if I can't get this modification faff sorted out

Jamie, you have a PM with a couple of contacts.

Thanks Mike, PM right back at you

Jamie,
The KR2 was one of the most popular aircraft featured in the "New Projects" section of our magazine in the seventies and eighties. The LAA must hold a host of approved modifications for this type. I notice however that quite a few that come up for sale are overweight and hence are sold as "single seater only". There may be many abandoned projects on that issue alone. Colin Hales and Nadine Bruans got around this weight/performance shortcoming by getting approval from the PFA to fit a Jabiru engine in exchange for the VW to their KR2 prior to their flight to Australia - the article on the journey appeared in the March/April 2003 issue of PF.
On the issue of the Europa elevator problem and subsequent modification to correct it, did the PFA came to the rescue to iron out the design solution rather than an individual owner/member submission ?

I'm aware of the Europa elevator mod - I fitted one as neither the owner, nor my dad who was his inspector could fit down the fuselage to install the new parts to the mass balance

I don't know who designed that particular modification, but the gentleman who owned that aircraft was just issued with everything he needed to know.

The Europa is much more popular than the KR2 so it's fair that it gets more attention.

I know of a couple of approved modifications on KR2s - but haven't got the foggiest idea how to retrieve the documentation on these mods. Off hand, I know that Colin changed his engine to the Jabiru, and Ken Atkinson built one with a long tail - I read Willie Wilson's flight test report to PFA Eng on that aircraft.

I'm not interested in finger pointing - I'm just after a copy of the mod sheets someone before me has presumeably submitted to get these Mandatory mods approved.

I just want to copy someone else's already approved Mod Application for the Mods described in the narrative and sketches I've been sent and send them to LAA Engineering for a quick acceptance.

Perhaps I'm searching for something I don't need? I'm in the petrochemical industry and before this had a go at RAF Initial Officer Training. The standard of writing required to pass IOT was exemplary, in that when writing a document, one writes exactly what one means and everything is expressed, not implied just to ensure that there is no wooliness anywhere. In oil & gas (and anywhere else involved in things which can go BANG) everything we produce has a formal document reference number so that it can be clearly referenced.

Is this really just a case of filling out a Mod form for these Mike Whittaker Mods, include Francis' narrative and the sketches and have my Inspector confirm that they have been incorporated?

Even still, I'm still in a grey area with a KR2. I was sent the Mike Whittaker mods, which, according to the narrative, were commissioned by a builder of a KR2S. They cover a variaty of areas, such as wing spars, fuselage longeron tripplers, strengthening of seat belt attachments, extra foam ribs if not using wet wings (which again is something I thought was not allowed in the UK - and if so why mention it?) and more plywood beefing up the tailplane/fin attachment area.

The narrative states that there are areas of the KR2 left wanting, and:

Extract:

9. The airframe of the KR2 was designed by stretching the single seat KR1 with very little increase of material sizes. Consequently the airframe has little or no reserves of strength in the area of the main wing spar and wing attachments. We therefore cannot increase max gross weight for the standard KR2 or KR2S above 900lbs, unless strengthening modifications are made as specified by Mr Whittaker.

I read that as an opportunity to investigate increasing my AUW of my KR2 with new spars and wing attachments as per the sketches - but an email from Francis knocked that one on the head on CofG range grounds. Fine, so I phoned Francis to ask if I needed new spars as per the MW mods.
His answer was: "Yes if you want to fly at higher weights"
I replied saying "But your email just said I couldn't fly at higher weights with a KR2 - so do I need these mods?"
"I suppose not" was the final response.

Again though, this seems to be a complete mods package - I anticipate problems just leaving out the bits I don't fancy and given how marginal on payload the KR2 is, I'm loathed to make new heavier spars when they're intended for an AUW allowance I'm never going to get.

This is a nightmare

It seems that someone somewhere is confused about the differences between a KR2 and a KR2S. I regard them as separate entities and there should, to my mind, be a separate list of mandatory mods for each type. As it is, they're all mashed in together and some kinda apply and some kinda don't - i.e. these are all part of a package of madatory mods but if you're staying at 900lbs AUW some are pointless. On top of these are other issues such as the new seats most UK KR2 examples seem to have etc.

I feel it would clear things up no end if there was just a concise list of everything which needs to be done to build a compliant example of each type - as well as a copy of the pre-approved solution used on another example of type

Jamie,

This is probably hopelessy simplistic, but I'll suggest it anyway.

If you look on G-INFO for aircraft type KR2 then there's 2 pages of aircraft. You probably know this.
Have you realised that for home built aircraft the Manufacturer field on the form is the person who built it. If you work though the list you can compare the owner with the manufacturer. Where they match you then have the name and address of the owner/builder.
I've not gone though the full list but I've already found 4 still owned by their builder.

These people may be worth contacting in connection with your problem, assuming that whatever shortcomings there are in the plans have been resolved on the flying fleet.

UPDATE: Ah! Slight flaw in my plan. Many (but not all) of them have no CofA expiry indicating they are probably still being built. Might still be a source of info and support though.

Jamie,
Be in no doubt that I am sympathetic to your concerns. I would have thought that the LAA would have specified the definitive modification work required in order to achieve permit to fly status when you registered the project. This is especially important when structural components and airworthiness are involved. The "nice to have" ones of a non structural kind can be "weeded" out by the builder. As I understand it, you have to apply to incorporate each mod on an individual basis rather than lump the whole lot together as one package. To have to rework and re-justify existing and approved modifications to type could be construed as an abandonment of support by the engineering dept.

Colin Hales is digging out contact details for a gentleman in Redding who has recently completed a KR2 which Francis D has inspected.

Hopefully I shall have a way forward with my existing airframe

Hi Jamie,

I can sympathise with your plight - I'm building a taylor monoplane and had great difficulties with elevator control cable tensions varying with the range of travel of the elevator when everything was built as per the plans. I have inspected several TM examples which have been flying for years, and all seem to have come up with their own solution to the problem.

Upon asking engineering for a mod that I could do to overcome this problem I was told there wasn't one and that the individual aircraft I had seen were probably signed off by their inspectors on a best practice type basis. My inspector would not accept this route (and I don't blame him) so I had to submit a mod of my own. It was accepted and I now have a control system that works properly. Will this mod be available to other builders? I doubt it. It certainly hasn't appeared on the list of standard mods on the old website.

Ok my mod may not have been suitable to offer as a standard mod, but anyone building a particular type should be able to get the details of any mod that has been done before. This would save engineering and builders both time and money.

Phil Burgess wrote: Ok my mod may not have been suitable to offer as a standard mod, but anyone building a particular type should be able to get the details of any mod that has been done before. This would save engineering and builders both time and money.

Particularly as it states on the Mods section of the website that applications will likely be rejected if there is already an approved mod which serves the same purpose!

It would save folks re-inventing the wheel, less Engineering time and more productive work on aeroplanes.

Of course, it may be the case that an approved mod may be approved on the basis of other differences rendering it unsuitable for a different aircraft - but access to all the mods would allow clarity at least of overall solutions which are approved as a number of Mods.