Aerobatics

[GT3]

As I don't have a personal copy of the ANO at home, and it was a few years since I did law at the college. Can anyone tell me what the rules are for practicing aerobatics over built up areas?
In particular small villages and schools.
Cheers

[Loki]

Rule 18 says something like not to be carried out over a congested area of city town or settlement.

Or in controlled airspace




http://www.caa.co.uk/docs/33/CAP393.PDF

[eyeinthesky]

Loki has it right from a law point of view. Small villages and schools do not generally constitute a 'congested area'.

Being a good neighbour might suggest that you should not do aerobatics over any population, but this is difficult in the UK. The (few) times I have done aeros, I have done a few and then moved somewhere else before doing some more.

Of course, it's a good idea to identify the schools so that you can steer to avoid them if everything goes wrong!

Been annoyed by a few aeros in your area recently, GT3?

[GT3]

Not me but the school my mother works at. A local vilager does his aeros twice a week over the villiage and the local school. There is some concern when he "switches off the engine" from the Headmistress as to where it might come down if he doesn't recover it.

[San Expiry]

Suggest to your mother that she gets the little darlings out in the fresh air (perish the thought!) and watch aforementioned aviator. You never know, it migth just inspire a little girl or boy to try it themselves one day.

[throw a dyce]

Part of the H.A.S.E.L checks for Spinning,Stalling and Aerobatics.
H- Height -Sufficient to recover by 3000' agl.
L -Look out- Clearing turns.Location- Clear of cloud,built up areas,controlled airspace and airfields.
This is just off the check list but should be a good indicator of where a pilot should conduct aeros.I think the 3000'agl is incase the engine stops,so you have time to do something about it.

[Human Factor]

I think the 3000'agl is incase the engine stops,so you have time to do something about it.

Historically, it comes from the military. 3000' is the point at which, if you haven't recovered from your spin, you step out and get another aeroplane.

[eyeinthesky]

Another thing:

Quote
he "switches off the engine"
unquote

Unlikely! What is actually happening is that he reduces power (maybe to idle) during the downwards part of the manoeuvre to prevent overspeeding. It is difficult to hear the idling engine of an aircraft which is approaching to land, so impossible from 3000ft or more.

As for the general concerns of the Headmistress... the little treasures have more chance of being run over by a passing tractor than they do of finding their playground full of smouldering aluminium following a failure to recover from an aerobatic manoeuvre.

But I suspect your tongue is firmly lodged in your cheek...

[Flybywyre]

I think you will find that Anotherthing put

switches off the engine

in inverted comma's for a reason

[barit1]

Please keep in mind that many primary training manuvers are not defined as aerobatics, even though the uninformed observer may regard them as such. Stalls (power on & off), lazy eights, chandelles etc. are good practice for any pilot whether 10 hours or 10,000.

The schoolmarm likely thinks anything other than straight & level is "aerobatic".

[BackPacker]

Actually, the engine might really be stopped

I occasionaly fly a Robin DR2, which is cleared for aerobatics (although I'm not). This machine is also cleared for *inverted* (negative g) manouvres, but it does not have an inverted fuel or oil system. Under prologed (more than three seconds, I think) of negative g, the carbs over- or underflow, or whatever. The technical details are beyond me. In any case, no more fuel gets into the cylinders, and the engine stops producing power. As long as you have sufficient forward speed, it will keep on windmilling and as soon as you build up positive g again, the engine will catch up immediately. If you don't have enough forward speed, the engine will stop dead. Easily remedied with the start switch or a dive. It's all a matter of planning.

This may sound very scary (both on the ground since the sound of the engine actually dies away, and as you read this) but it is not. The engine was running properly, so your throttle/mixture/pump/whatever settings were correct. It's just that the fuel doesn't reach the engine for a few seconds, but as soon as that fuel flow is restored, the engine will function as before. Just make sure the manouvres don't last too long or the engine may shock cool. And since the oil system most likely isn't capable of supplying oil under negative g, you might not have enough lubrication anymore after more than a few seconds of this.

So if done properly and carefully, yes the engine may come to a dead stop during certain manouvres, but it's a non-event if you planned it that way.

[barit1]

BackPacker's absolutely right, and stoppage is very typical of carbureted engines. My father taught aero as part of basic & advanced training syllabus in WWII and this was considered normal.

On the R-985 engine there was an optional gravity check valve at the carburetor fuel inlet. If installed, the valve would prevent the carb from flooding, and so several seconds of useful power were available when inverted.

But fuel injection or pressure carburetor can solve all that!

[BackPacker]

I checked my Air Law book and it says a number of things on Aerobatics. No minimum height is specified though, although a minimum of 3000 feet AGL for a non-display-approved aerobat seems very sensible.

Anyway, "No aerobatic manoeuvre may be flown over the congested area of any city, town or settlement". And later on: "The view of the CAA appears to be that any area depicted on the CAA 1:500 000 charts as built-up area qualifies as a congested area. Similarly, any settlement with clearly defined boundaries is also a congested area."

So check if the city/school is listed on the CAA half mil map. Then kindly ask the guy to move over somewhere else.