Light Aircraft Association

Have looked thru the TLs but can't find any that answer my question.

I'm considering an EFIS as primary flight instrument - to provide GPS & Map, ALT, ASI, VSI AI, DI and engine monitoring - Usual sort of stuff. Fitted to a plastic aeroplane with a nosewheel!!

What must I fit as back-up. I'm told that analog ASI and ALT is req'd for Group A, but for microlights it's OK for a combined electronic ASI and ALT (e.g. MGL ASX-1). Is this the case? and is there a route to attempt to pursuade the LAA otherwise - with a properly designed solution for independent electrical supply for the ASX-1 (it only takes 80mA, simple independent PSU supplied from alternator AC)

Also - Is there any requirement for back-up engine instruments?

I know there's still talk and night/IFR on permit planes. If it happens, is there an indication of how things might change as a result.

I appolgise if I've missed the TL that covers this - otherwise advice appreciated.

Best place to check in readable form (unlike the Air Navigation Order) is CS-VLA at

http://www.easa.europa.eu/agency-measur ... _18_RM.pdf

See Page 1-F-1 Section 1301 onwards


LAA have a good guide to it here
http://www.lightaircraftassociation.co. ... 0CSVLA.pdf

Regards
Steve

I too would like an answer to this. A friend has asked me to perform the flight tests for the initial permit issue for a nice little 2-seat VLA and he seems only to have an EFIS with little else by way of "steam-driven" instruments for VFR back-up. The only photo I've seen doesn't show the panel clearly.

As a retired commercial pilot, it seems to me that permit light aircraft should be subject to the same requirements as certified VFR aircraft i.e. a bare minimum of ASI, altimeter and magnetic compass. I've seen CS-VLA 1303 Flight and navigation instruments "The following are required flight and navigational instruments: (a) An airspeed indicator; (b) An altimeter; (c) A magnetic direction indicator" but I can't see any reference to whether this applies to permit aircraft.

What should I do? Decline to carry out the flight tests until suitable back-ups are installed, or just do the flights and hope that the friend (trainee pilot) has researched this topic for himself and satisfies whatever requirements he's discovered? His aircraft is several hundreds of miles away from where I live.

Replies please to [email protected]

I asked this question a few years ago and was told that only mechanical analog instruments were acceptable as a back-up. ASI, ALT and whisky Compass. I bit my tongue at the time as I considered this a case where the rules were written in an age gone by, and needed to be brought kicking and screaming into the 21st Century.

IMO the rule should be an indipendant system from the main system. For example an other electronic instrument with an internal battery backup should be OK. I haven't got details to hand at the moment but I did spot that the recent approval of the Lambert Mission 108 was approved by the LAA with electronic stand-by instruments, so perhaps there is a more pragmatic approach now?
Edit: see the standard panel fit here http://www.lambert-aircraft.com/eng/M108.htm

These days electronic instruments are just as reliable as the old steam ones, yet we have never been asked to provide backups to total traditional panels. Go figure as they say.

Jonathan, when I test flew my own aircraft, 12 years ago , I seem to remember that part of the application process was having to fill in the type of instrumentation , manufacturers part no. and serial numbers of said instruments prior to Permit to Test. I assume that your colleague will have done a similar thing.
But irrespective of the minimum requirements, I would definitely prefer to see conventional ASI/Alt. with pitot/static lines going in and out of them.
And while I'm here , I would just like to point out , in the best POSSIBLE taste [: :] . It does rather bug me when people refer to conventional instrumentation as "the old steam driven instruments". It implies that they are inefficient , unreliable and obsolete. None of which is true ! And conventional instruments don't lose their signal or have the screen "freeze up" on you . Oh and another thing, when you're in the CAA Desert , there ain't any battery shops.
It's a no-brainer surely ! If a glass cockpit B747-400 has conventional stand-by instruments, then surely its good enough for a PtF type recreational homebuild.
God I wish the weather would improve. All I've done is sit at this bloody computer all day.

If a glass cockpit B747-400 has conventional stand-by instruments, then surely its good enough for a PtF type recreational homebuild.

For years many of us have complained that the CAA treated light aircraft with watered down commercial transport rules, many of which are wholly inappropriate. Thank heaven they are moving away from that attitude with the GA Unit so be careful what you wish for Chris.
That said I agree that glass panels should have an analogue compass, airspeed and altimeter because they are pretty well bullet proof and provide all you need to get out of jail free (in VFR) should your wonder panel decide to go pear shaped. I do not understand why some members complain about this obviously sensible safety net.

Brian Hope wrote:

I do not understand why some members complain about this obviously sensible safety net.

Precisely what I'm saying old boy ! If it's good enough for a B747, then it's good enough for a PtF type homebuild .

Ooo, seemed to have touched a nerve there Chris

When I refer to Steam driven instruments, I am using it as shorthand for traditional analogue mechanical instruments. I am not implying anything regarding age, reliability or suitability. Having said that there is no escaping the fact that it is old technology. Nor the fact that many fitted instrument are past their best.

As a person that uses the latest tec every day, I still prefer an analogue pointer on an instrument that does only one job. Digital displays also look so wrong on some aircraft, not that has anything to do with EFIS stand-by instruments.

In my post above I was referring to electronic instruments, not EFIS or other Panels. For these, I agree that a stand-by set should be fitted. I do not agree that they should only be traditional mechanical instruments.

Touched a nerve ? ? No, no, no ,,, and don't forget , it was said in the best POSSIBLE taste
Blimey mate , don't want to get like some of them tetchy prima-donnas one sees on some of them other forums ! !
I certainly know what type of instrumentation I prefer, but if others are happy with their layouts and it satisfies their Inspectors , then what the heck,,, . Especially if they refer to it as conventional instrumentation and not "the old steam type instruments" [see, I'm still laughing]
I guess it is one of the great advantages of the fantastic regime that we are privileged to operate within.
Long live the LAA .
Better go,,I'm starting to get possessed by bloody emoticons.

We have got a little off topic here. The question remains. Can another electronic instrument be used to provide airspeed and altitude information or must it be separate mechanical instruments? I too would like to use something along the lines of the ASX-1.

Paul, none of us here can give a definitive answer, you would need to speak to LAA Engineering for that. However I did post that the Mission 108 had been approved with an electronic Stand-by ALT and ASI. In fact they use a LX BU57. Check out the July 2015 Light Aviation, or the link I gave above.

pbflyer wrote: The question remains. Can another electronic instrument be used to provide airspeed and altitude information or must it be separate mechanical instruments?

As Ian says, the question should really be put to LAA Eng. Dept. They'll give you one answer - The right one ! Forums are fine for what they are , but I've seen too many people ask a question on a forum, and getting so deluged with opinion that they end up needing The Samaritans rather than LAA Engineering.
Ian's opinion regarding instrumentation maybe slightly different to mine, that doesn't make him a bad person and I can't help being a bit traditional in my preferences. [N.B. this is only opinion]
But the first thing LAA Eng. will want to know is, what type of a/c you have in mind and do you intend to fly day/VFR or opt for "the dark side". If it is the latter, then it has been reasonably documented as of late. For day/VFR ,then as stated previously, it is highly likely that your Inspector will be your guiding light and with the advent of common sense and pragmatism, the application of good workmanship and good quality components that come with some sort of certificate of conformity , you'll probably find that you have a surprisingly free rein Paul.
The only thing I will say which is my opinion , but probably fairly unanimous is ; Don't try and second-guess your Inspector though .

Very sensible advice gentlemen. Many thanks for that. I will take it up with my Inspector and the LAA Engineering office and see what they think.