2.4 fail safe function

[Alan Cantwell]

Its mandatory, and a legality, that, if a model is fitted with a fail safe reciever--ie, a PCM, one, that the recievers fail safe is set to at least throttle shut, i believe that most/all 2.4 recievers have at least a throttle failsafe built in, does anyone know the legalities of not setting the 2.4 recievers, does anyone NOT set them? are we breaking the CAA law if we dont bother?

Edited By Alan C on 25/04/2011 21:53:15

[Alan Cantwell]

would help if i spelt the thread title correctly

[Alan Cantwell]

SO, lets just ask, do you set your fail safe function? come on, be honest

[BB]

Always use mine Alan. I thought the use of, was mandatory if flying at a public display.

 

BB

[Martin Harris - Moderator]

Yes.

 

But I believe that it's only a legal requirement on >7 kg models.

[Phil 9]

Martin that is not quite correct.

 

if the model has a failsafe it must be set whatever size model to at least run the motor at its lowest speed.

 

a model of less than 7 kg can be run with equipment without failsafe but if the option is there it must be used on the throttle at least

Edited By Phil B on 25/04/2011 22:38:38

Edited By Phil B on 25/04/2011 22:52:29

[Phil 9]

wth my dx6i and ar6200 rx on loss of signal the motor will go to minmum throtle but the servos holds last postion.

 

for models over 7kg a true failsafe is needed with servos going to a preset positon.

 

I think the confusion is caused by the manufactures using terms like "smart fail safe" for a system that is not a failsafe

Edited By Phil B on 25/04/2011 22:46:48

[Biggles' Elder Brother - Moderator]

I always set it. Personally I'm not aware the situation is any different between 35MHz and 2.4GHz on this issue. I've always assumed setting the failsafe was a compulsary part of setting up any model.

 

BEB

[mal brewer]

Phil b is quite correct,if the radio in use is fitted with a fail-safe default ,it must be used,irrespective of model size or weight..............................Mal.

[Alan Cantwell]

so we are all agreed it needs to be set, but lets just clarify a few points, yes, its mandatory for any model over 7kg, but its only a legal need to have the throttle shutting, its not a legal need to have all servos go to pre sets,

 

its not mandatory for a fail safe to be fitting to a show/event model, under 7kg, thats up to the show organiser

 

any model, over and above 7kg, if fitted with a failsafe of any sort, that fail safe must be set to at least idle for ic, or off for lekky,

 

but thats not the point of this, do me a favour, next time you see a 2.4 being used at your field, ask for a failsafe demo, i have a big hunch many of them are not set, because the operator has no previous knowledge of a fail safe function, and i think many would be suprised they have one,

[Martin Harris - Moderator]

I'm not disputing the BMFA position on this Phil, but as far as I am [was!] aware it is not a LEGAL requirement unless the model comes under the Air Navigation Order pertaining to > 7 kg models.

 

The current edition of the BMFA handbook makes reference to 2.4 GHz sets having failsafe but all references state "should" and not "must".

 

Having just checked it on the BMFA website and CAP 658, it comes as a surprise to me as they both infer that a failsafe is NOT a legal requirement in any case by the use of the word "should". However, as CAP 658 strongly advises the use it would be foolish to ignore the advice.

 

Edit - Having been interrupted since starting this reply, there have been several posts - one referring to checks on models and I would agree that many people are totally unaware of failsafes - I asked the question of one person on Saturday and got a very blank look as a reply!  As we operate our club to BMFA guidelines, it's certainly part of what anyone checking models ought to be aware of and this is a good reminder to highlight this as other "inspectors" may be missing this!

 

Edited By Martin Harris on 25/04/2011 23:37:50

[Phil 9]

1.2.6 Radio Control Failsafes

Any powered model with a radio control failsafe
device must have that device set so that, as a
minimum, its operation causes the engine/motor to
run at its lowest speed (stopped in the case of
electric powered models) and specifically not to hold
the last position of the engine/motor control
regardless of the other functions of the failsafe. It is
the responsibility of the pilot to demonstrate this
function on request.

this part of the handbook says must

[Biggles' Elder Brother - Moderator]

I shall ask - but nearly all our 2.4 fliers are ex 35 fliers, so there is no excuse for them not knowing about a failsafe really. But I agree, it would be interesting to find out.

 

BEB

[Phil 9]

I would say that alot of them on 2.4 would be set as it is set during binding and the tx (I would imagine) most will have the throttle set to low even if they were not aware it should be.

but maybe more should be done to make people aware. could a fail safe demonstration be a compulsory part of the A test?

 

 

Edited By Phil B on 26/04/2011 00:00:32

[Martin Harris - Moderator]

Please don't think I'm arguing about the wisdom of using failsafe but you're referring to contest rules - not law.

 

Personally, I think that the BMFA should revise the wording to make it compulsory for members to use failsafes correctly where fitted and clarify whether CAP 658 fully reflects the intention or wording of the ANO.

 

Phil - your last point makes a great deal of sense and I'll mention it to our ACE who is a member of the achievent scheme committee.

Edited By Martin Harris on 26/04/2011 00:06:42

[Phil 9]

yes you are right Martin and that was the contest rules sorry.

 

you are correct that it needs clarification but it looks to me like one of those legal anomalies. where it is not the law that you should use it but if you cause an accident because you have not used it then you are responcible

Edited By Phil B on 26/04/2011 00:17:30

[Tom Wright 2]

The thread raises some interesting points , how about a large EP powered glider ,the esc should take care of signal loss ,but if further fail safe is not programed ,there is a strong chance of a long uncontrolled flight into the unknown,may be were possible full up elevator and half rudder deflection would minimise the risk,what do others think?

 

TW2

Edited By tom wright 2 on 26/04/2011 00:33:20

[Phil 9]

 I would imagine a powered glider would come under the same rules of powered models

 

I am not sure what would be the safest option here?

 

Edited By Phil B on 26/04/2011 00:30:22

[Ian Jones]

The breaking the law question is not quite black & white as legal/not legal. It's all in CAP 658 (chapter 5 in this case) which in itself does not make anything legal/illegal however it is a "Guide to Safe Flying". In any assesment of liability CAP 658 is the authoritive document that will be referred to so any deviation from the guidelines would tend support any such case.

 

Hence in the BMFA handbook: "Whilst the recommendations in CAP 658 are not regarded as legal requirements, one of the reasons why it is issued by the CAA is to provide a guide to what would be considered ‘reasonable practice’ in the event of a model flyer being prosecuted by them under the Air Navigation Order. "

 

So the bottom line is that we should all familarise ourselves fully our radio equipment and if it has a failsafe of any type then we must not just accept that it's there; we should actually set it and know what we have set it to.

 

Ian

 

(I tried to lighten up a bit on this with a few smileys but unfortunately when I tried "The area you are attempting to access is forbidden" was displayed instead of the smileys.)

 

 

 

 

[Martin Harris - Moderator]

Tom,

 

That is "covered" in the handbook by an invitation to consider the intent of the recommendation/requirement (interpret as you see fit!) to avoid flyaways:

 

...obviously the ‘setting of throttle’ does not apply. You
should remember that the reason that the CAA
requires failsafes is to prevent flyaways, not to
deliberately crash the model, and you should set the
controls of your model with this in mind. Application
of spoilers, ‘crow’ brakes or even rudder and
elevator to spin the model might be appropriate

 

To add to the confusion, note the use of the words "CAA requires"!

 

Hopefully, we're all in agreement with Ian's last paragraph?

Edited By Martin Harris on 26/04/2011 00:30:06

[Tom Wright 2]

Thanks for that Martin,don't you think in reality that say a 12lbs scale model would crash if any sort of fail safe was employed to prevent a fly away?

 

TW2.

[boggy]

can i come at it from another direction and ask the OP " if its available,why would you not set it" ?

 

surely its going to crash anyway TW2? 

Edited By boggy on 26/04/2011 00:44:20

[Phil 9]

Boggy I think the original point was they are not being set because people are not fully aware of them not because they where ignoring them

[boggy]

thank you phil, i am reasonably new to Rc so have only ever used 2.4.

so if i had converted from 35mhz chances are,being male I would have not read my manual properly and not set it ?

 

that was meant light heartedly not a dig!

[Martin Harris - Moderator]

Tom - not really sure what you're asking but it's unlikely that a model in failsafe would survive unscathed in the event of total lockout. The point is to minimise the chances of interfering with any air traffic (as it should be at least 100 feet above you) by closing a throttle or deploying airbrakes/crow flaps etc.

 

There has been a lot of debate about the positioning of control surfaces in failsafe but I'd consider a stalled airframe crashing on or close to a model flying field to be potentially less hazardous than one disappearing uncontrolled in the direction of habitation, roads or livestock.

Edited By Martin Harris on 26/04/2011 01:14:06