Article 16 Benefits & Failsafe: Cut Throttle a Legal Requirement?

[GaryW]

9 minutes ago, Cuban8 said:

Not forgetting the late, great, Roy Lever's Parachute recovery system on his Merlin radios, if memory serves.

Those of a certain vintage will recall it was a sure fire safety device. 😜

 

 

 

I remember watching Roy on Model Mania many years ago

 

 

 

[leccyflyer]

3 hours ago, GaryW said:

 

That is true Geoff... But i'd rather the engine/motor be dead stick than a spinning engine/prop come out the sky on the end of a model .. as fpr being in gliding range of the patch... strictly speaking if im right we shud all be flying within the perimeter of the flying field rather than in a way where a model wudnt be in gliding range of the patch which if amodel is too far out to make it back to the patch then maybe models are flying too far out to begin with????

It's right there in black and white, entirely in your own words.

[GaryW]

19 minutes ago, leccyflyer said:

It's right there in black and white, entirely in your own words.

 

Please give over & move on ,,,, like a dog with a bone looking to cause row & argument.. It was a question clearly indicated by the question marks not a statement as you claim it to be nor was I stating anything

Edited May 15, 2024 by GaryW

[DocPrinter]

I was hoping this wouldn't happen. I was specifically asing about legal requirements, rather than BMFA guides, or even rules that may not be legally binding. I do however appreciate that the BMFA rules may need to be followed in order to fly under their insurance.

 

@Ron Gray that's excellent, thanks. Almost exactly what I had originally planned. Didn't think it was too far fetched. I do have GPS, barometer, and high spec IMUs on board. It would have air speed sensor but thought that would be vunerable in my learning stages!

[john stones 1 - Moderator]

BMFA offer guidance and publish rules set in place by others.

Failsafe has many answers as seen above, satisfy yourself you do it safely, that's pretty much it.

[Philip Lewis 3]

1 hour ago, john stones 1 - Moderator said:

BMFA offer guidance and publish rules set in place by others.

Failsafe has many answers as seen above, satisfy yourself you do it safely, that's pretty much it.

That is the voice of reason and a perfect summary of the situation.

[GrumpyGnome]

Out of pure curiosity, a couple of questions about this 'loitering' using GPS....

 

Is the idea you pack up your stuff to get closer to the model and re-acquire control? What if you re-acquire control whilst you are driving? 

 

What happens if GPS contact is lost (e.g. battery flat)?

 

What happens if power to the models rotors/propellor is lost (e.g. battery pack flat)? Will the 'loiter' function try and maintain level flight, resulting in a stall?

 

I'm just being curious..... I could Google it I suppose...

[Neil James]

Some years ago an officer from the CAA Safety & Regulation Group (SRG) told me that they expected a failsafe to cut the motor and bring the model down vertically as quickly as possible. He specifically mentioned that damage to the model was not a consideration and that SRG expected that flight would always take place within the boundaries of the flying site so that there would be no third party affected by this behaviour. 
 

This was before the widespread use of dr*nes.

[GrumpyGnome]

I'd hope that the current relationship between the BMFA and CAA now means the SRG are better informed........

[DocPrinter]

On 16/05/2024 at 05:52, GrumpyGnome said:

Out of pure curiosity, a couple of questions about this 'loitering' using GPS....

The smart fail safe guidance appears to be intended for autopiloted flights supervised by a ground operator who would have retained VLOS with the drone (distinct from RC plane, inclusive of GPS equipt rotorcraft) perhaps with a little walking around buildings etc. I agree with measures to limit ground distance travelled by dumb rc models, and without inherent stability in the design or stabalisers (slighly smart!) aiming for a glide down would be optimistic.

On 16/05/2024 at 05:52, GrumpyGnome said:

Is the idea you pack up your stuff to get closer to the model and re-acquire control? What if you re-acquire control whilst you are driving?

 

I am hoping that the need to use it would be vanishingly small. Therefore some of these situations may seem far fetched and indeed avoidable. The model would not be out of VLOS, so driving not needed. Perhaps a short walk. Perhaps your plane has entered an area with a lot of interference and the short walk allows the Tx to overcome that and regain. Perhaps a battery failed (or wasn't charged!) in the tx. If control is reaquired while moving it will remain in loiter mode until the controls on the tx are moved.

On 16/05/2024 at 05:52, GrumpyGnome said:

What happens if GPS contact is lost (e.g. battery flat)?

GPS is powered by flight battery via a BEC in the controller stack rather than the ESC BEC. Using non ESC BEC means the plane is already safer than most single battery ESC BEC models, allowing dead stick servo control if the ESC smokes and doesn't take the battery with it. Battery flat is therefore the same risk level and hazard as most other electric RC aircraft, although the drone gear does grant me telemetry on current consumption and voltage levels. Battery flat, servos can't move, controller and ancillarys off, plane becomes dumb brick.

On 16/05/2024 at 05:52, GrumpyGnome said:

What happens if power to the models rotors/propellor is lost (e.g. battery pack flat)? Will the 'loiter' function try and maintain level flight, resulting in a stall?

The flight controller knows the orientation of level flight via the internal solid state gyros. It will try to maintain level flight but not at the expense of airspeed. It uses GPS to generate an estimate of wind speed/direction and works to remain above a predefined stall speed which is tested during setup. It will therefore enter a glide slope down. These systems can however use airspeed sensors and laser/sonic height gauges for final landing aids.

 

There are different failsafes for GPS issues, battery issues, radio issues, and probably more. Many Ardupilot setups have a seperate radio link for telemetry to a ground station and it is possible to fly the plane from a game controller via the ground station if things get really testy!

 

To save you an internet search: https://discuss.ardupilot.org/

Edited May 17, 2024 by DocPrinter
Add link. Typos

[Zflyer]

Given all that why do you want to fly?

[DocPrinter]

18 minutes ago, Zflyer said:

Given all that why do you want to fly?

 

...

 

1 hour ago, DocPrinter said:

I am hoping that the need to use it would be vanishingly small.

 

For the ~99%+ of flight time that isn't covered by radio fail safes.

 

I asked the question on here because someone from BMFA was saying it was a legal requirement to cut throttle, which they haven't been able to back up with reference, and appears to be inaccurate given the the CAP 722 points someone has kindly extracted on this forum.

 

I am someone is interested in both automatic and remote piloted models. Aside from automatic flight I am interested in fun fly and others. I feel it should also be a requirement for any remote drone pilot to be able to fly manual (full manual likely impossible on multirotors), and the best place to learn is within a club setting.

 

 

 

Edited May 17, 2024 by DocPrinter

[John Lee]

1 hour ago, DocPrinter said:

I asked the question on here because someone from BMFA was saying it was a legal requirement to cut throttle, which they haven't been able to back up with reference, and appears to be inaccurate given the the CAP 722 points someone has kindly extracted on this forum.

 

They may have been thinking of CAP 658 - "Model Aircraft: A Guide To Safe Flying", which was the then 'Bible' and often quoted and referenced for many years (and from my experience still appears in some Club Constitutions & Safety Rules). However that was withdrawn by the CAA in January 2021 and was superseded by CAP 722.

 

In CAP 658 it stated:

 

"Failsafes

Any powered model aircraft fitted with a receiver capable of operating in failsafe mode should have the failsafe set, as a minimum, to reduce the engine(s) speed to idle on loss or corruption of signal."

[DocPrinter]

@John Lee gotcha, that makes sense! This probably wouldn't have changed if it wasn't for growing commercial interest in unmanned delivery & security drones.

 

 

Freight companies often have a great get out of jail card between themselves and liability when they employ someone to drive. When using fully auto drones they can't dodge much liability.

 

Tiny probability of serious issue with a few hobbyist rc aircraft not a big issue. Get a lrge fleet of a drones over a number of national urban hubs with competing suppliers cutting as much cost as possible and following legislation makes a lot of sense.

 

For me, I have the gear on board that is capable of landing safely, I'd just like to use it if the worst happens to save my craft. Edit: ...and come down in what I consider a safer manner.

Edited May 17, 2024 by DocPrinter

[GaryW]

3 hours ago, DocPrinter said:

 

I feel it should also be a requirement for any remote drone pilot to be able to fly manual (full manual likely impossible on multirotors), 

 

 

 

 

Some Quads/Drone can be flown manually  with onbboard built in automated & auto stabilization swithed off,,, so as to be flown totally unaided in the same way helicopters are by switching the GPS & stabilization off  which both of my Blade 350 QX3's can be flown totally manually

Edited May 17, 2024 by GaryW

[DocPrinter]

@GaryW interesting. I thought they always had a degree of stability control. Thanks.

[Simon Chaddock]

Surely all the early full size helicopters, like the Bell 47 were entirely manual. Auto stability being built into the design of the rotor head.  Electronic stability was simply not available. It follows that if the rotor heads follow full size practise models should in theory be able to fly "manual".      

[DocPrinter]

@Simon Chaddock  When I was referring to multirotors I ment stuff like the tri/quad/hexa/octocopters. However, while I'm not overly familiar with RC Helicopters I beleive the fly bar system on helicopters to be a primative mechanical version of the sort of electronic stabalisation I had previously thought was on all multirotors to provide things like rate limits that you usually see discussed on youtube comentaries.

Edited May 17, 2024 by DocPrinter

[DocPrinter]

Yeah, until you get big I thing there is always stability control on tri/quad/hexa/octa/multi rotors.

 

https://www.forbes.com/sites/quora/2013/12/23/what-makes-the-quadcopter-design-so-great-for-small-drones/

 

It's just some modes will be closer to manual like behaviour and others will baby the pilot.

 

Edit: Put another way if the gyro failed and the pilot could gain direct control (at least via mixers, rather than 4 throttles) there would be vanishingly few who could cope with an average sized hobby drone.

Edited May 17, 2024 by DocPrinter

[Simon Chaddock]

DocPrinter

I agree entirely. A quadcopter with fixed blade props is basically unstable and could not be realistically flown manually by any pilot. It relies entirely on the lightning fast responses of a gyro much as the 5th generation fighter jets do.

It always amazes me how such quads can hover virtually stationary over a landing point and fully compensate for wind gusts as well. 

[payneib]

23 hours ago, Simon Chaddock said:

DocPrinter

I agree entirely. A quadcopter with fixed blade props is basically unstable and could not be realistically flown manually by any pilot. It relies entirely on the lightning fast responses of a gyro much as the 5th generation fighter jets do.

It always amazes me how such quads can hover virtually stationary over a landing point and fully compensate for wind gusts as well. 

That's entirely false.

 

I've dabled with the below example, it fly's perfectly fine with the gyro switched off and there's very little input required for a stable hover. In "auto level mode" it sits perfectly still on its own. 

[Cuban8]

On 17/05/2024 at 12:19, Simon Chaddock said:

Surely all the early full size helicopters, like the Bell 47 were entirely manual. Auto stability being built into the design of the rotor head.  Electronic stability was simply not available. It follows that if the rotor heads follow full size practise models should in theory be able to fly "manual".      

I'm currently re-reading Christopher Kraft's autobiography about his career in aviation design and subsequent work with  NASA's mission control. During the 1950's he'd been a major figure in the development of a 'Gust Alleviation Device ' for the US NACA - essentially a development of the autopilots that were available at the time based on mechanical gyros and analogue electronics. The project was very successful and auto stabilised  transport aircraft that suffered from the often severe air turbulence that is found at the altitudes that most large aircraft were limited to back in the day. The clever bit was still allowing complete pilot authority over the system via the usual controls - not easy with 1940s and '50s electronics.

A fascinating read.

Edited May 19, 2024 by Cuban8

[DocPrinter]

@payneib what firmware was that using?

[payneib]

3 hours ago, DocPrinter said:

@payneib what firmware was that using?

Couldn't tell you. It was set up two or three years ago, and hasn't flown in over a year - drone flying is massively boring on a flat field. 

[DocPrinter]

@payneib most popular is betaflight as far as I am aware and while you can wind back correction I was under the impression gyro feedback was essential for the PID loops.