Overturned Caravan

[Brian_374582181]

Hi,

Well I phoned Alko last week to book it in. Unfortunately all the tech staff were at the show, asked me to phone back Monday.I know its not a remedy for bad practice but believe me from now on everything by the book, checked & double checked. Don't fancy a repetition of the last outings events.
I did take the new van out last week for a run around the block just to see how it felt, my other half came with me and she was severely stressed, said its worse than flying. Hopefully the ATC will help reassure her.
Well off to the show tomorrow perhaps have a chat with the Alko guys
regards to all.
Brian

 

[Lutz]

The ATC will not improve the "feel" of towing the caravan in any way. If it feels twitchy for any reason, it will remain twitchy even with ATC. It will only prevent the worst from happening.

 

[Brian_374582181]

The ATC will not improve the "feel" of towing the caravan in any way. If it feels twitchy for any reason, it will remain twitchy even with ATC. It will only prevent the worst from happening.

Didn't think it would. I assume you don't know its there until you get a problem. Still reassuring to know it can prevent the worst from happening. Incidentally towing with the Sorento I didn't find it twitchy but did find it very bouncy. Any advice on improving the smoothness appreciated

Brian

 

[ProfJohnL]

Hello Lutz,

Thats basically what I thought. It confirms there is no simple way on physically confirming the systems are active and cabable of fully functioning without taking special measures (like finding and air field)

Hello John
My question was not about how effective the systems are, but how can you tell under normal road conditions that the system is fully operational. However I am glad that your experience has proven that it does work and it may have saved you from an unfortunate experience.

 

[ProfJohnL]

Hello Brian,

I'm not sure from your description exactly what you are referring too when you say it "feels bouncy" You haven't told us what your new caravan is, so I wonder if its a twin axle.

It has been explained may times on the forum that the nose load of a caravan actually changes depending on how high the hitch is from the horizontal. For a single axle caravan the change in nose load vs height is relatively smooth and the rate of change is comparatively slow compared to that of a twin axle trailer.

In a twin axle trailer the axles and suspension interact with each other and create a nose load effect which can change very dramatically in only a few centimetres of hitch height movement.

this is why it especially important to take care in setting up the nose load on TA caravans.

If it is set up incorrectly there may be insufficient nose load which even under quite normal driving conditions may mean instead of the nose load continually pushing down on the ball hitch, from time to time as the outfit crosses bumps and dips in the road the actual nose load may go negative and momentarily try to lift the ball hitch.

This can be felt in the car.

The solution for this problem is up the static nose load.

 

[Lutz]

Hello Lutz,

Thats basically what I thought. It confirms there is no simple way on physically confirming the systems are active and cabable of fully functioning without taking special measures (like finding and air field)

But that applies basically to many other safety systems, too. For example, you have no means of checking whether your seat belts are up to the job, the air bags deploy properly, or the energy absorption characteristics of the vehicle body will protect the occupants as intended until involved in an accident.
Besides, I doubt whether very many people bother to check whether the ABS and ESP systems are working properly every time before they set out on a journey, either.
In some cases it may be possible to check the function of an electronic stabiliser simply by rocking the back end of the caravan sideways. However, it requires a degree of lateral compliance of the caravan's suspension and you have to get the frequency of the rocking motion right in order for this rather crude method to work. Maybe you'd even have to let some air out of the tyres in order to get enough amplitude, though.
The sensor of the LEAS system that I've got in my caravan is attached to the floor simply with double-side adhesive tape. I could pull it off the floor and give it a shake to see whether the system is working properly and then replace the tape again afterwards, but of course, that's nothing that one would do regularly. Also, one can hear the LEAS system go through a test cycle every time the caravan is hitched up to the car and the system is activated.

 

[Lutz]

Brian has also not stated whether his caravan is fitted with shock absorbers. Without them, the ride could also feel bouncy.

 

[John_374564913]

Dear Prof:
If I understand your below question correctly
Hello John
My question was not about how effective the systems are, but how can you tell under normal road conditions that the system is fully operational. However I am glad that your experience has proven that it does work and it may have saved you from an unfortunate experience.

Once I have coupled up I check that the green light is on for the ATC the light being mounted on the A frame if its green it indicaates that it is functioning and ready to be deployed. If by chance it is read then it has a fault and not active.
Whilst travelling in Austria we left the motoerway and took some very bad roads when I pulled into a layby we had to swing hard right and over a bad hump when we got out of the car the light was red so it had activated when I pulled in sharply. Wa a bit worried what to do because it was red but by the time I finished my coffee and pulled forward about two feet and checked again it had returned to green and off we went.
So if I am correct in my assumption of your question when its green its ok when its red its not

John

 

[Lutz]

With the LEAS system one can actually even see and hear the brakes being applied and released again as it goes through the test cycle when it is activated.

 

[DeliDave_]

Someone else may have said in the previous pages but so does the ATC you can hear it pulling the motor moving when its plugged in.Mine failed due to the car electrics not being wired in heavy enough cable,only off the rear power socket.This left it stuck on and I had the remove the actuating bar(all in the instructions) and rewire the 7 pin socket.It sometimes activates if I go out of storage lane too fast and its like a heavy braking very weird.

 

[Brian_374582181]

Brian has also not stated whether his caravan is fitted with shock absorbers. Without them, the ride could also feel bouncy.

What I actually mean't was the car suspension felt bouncy. Caravan is an Avondale dart single axle. MTLM is 1027kg.
Quite a bit lighter than the last one but about the same size. Possible it will be better with some weight in the back of the car.

Went to the show today and spoke with the Alko reps. One didn't seem to know much about it. Seemed to think it came on when you went round islands etc.
Two chassis on demo one worked one didn't. Not exactly confidence inspiring

 

[ProfJohnL]

Hello John,

I have no doubts that these caravan stability systems do make a significant contribution to the safety of towing, and as such I encourage caravanner's to consider fitting them, along with shock absorbers etc.

My concern is not with how they work, but more to how can you be sure they are ready to work when you start a journey. Unlike normal brakes and lights etc, there is no instant feedback.

At the risk of over labouring the point, indicator lights can and do sometimes fail to give the correct indication. I have seen (and condemned) on domestic and industrial controls where apparently they show a system is working satisfactorily, yet by other means can easily be seen to be faulty or potentially dangerous.

Basically a green light glowing may just prove the green light bulb is working, it doesn't necessarily prove the system behind the light is working. even if the system goes through an activation cycle when it is turned on, it is not actually responding to a motion sensors input, but a simulated signal. It is possible the motion sensor may be faulty.

From the other replies it seems there is no simple test you can do to confirm the actual operation of these systems, so you have to have faith in the design of the system, and can only report they have activated once you have strayed outside their detection envelope.

I am not trying to discourage caravanner's from fitting these devices, but until they have a situation where the system should respond, they wont know whether it really can respond.

 

[Lutz]

From the other replies it seems there is no simple test you can do to confirm the actual operation of these systems, so you have to have faith in the design of the system, and can only report they have activated once you have strayed outside their detection envelope.
I am not trying to discourage caravanner's from fitting these devices, but until they have a situation where the system should respond, they wont know whether it really can respond.

John, I think that you have overlooked the replies stating that the LEAS system, and according to Deli Dave, the ATC as well, go through an automatic test cycle when they are activated, whereby the brakes are briefly applied and released again.

What I actually mean't was the car suspension felt bouncy.

Even the car's ride can suffer through the lack of shock absorbers on the caravan. If the caravan's ride is choppy, this will transmit through to the car via the towbar.

 

[chrisbee1]

I have ATC fitted to my 'van. I find a quick 2 way flick of the steering at low speed will activate the system so it is possible to "test" it within a short distance of setting off. You cannot mistake it when the system operates. However, last year whilst in France at a service stop I noticed the warning lamp was red, indicating non-operation of the unit. Quite when in the previous 2 hours it had stopped working I don't know which in itself is a concern. On contacting ALKO on my return it transpired the log memory was full. Each activation is logged and I had inadvertently filled the memory. It is quite simple to clear the memory, something I now do as a matter of course.

 

[ProfJohnL]

Hello Lutz,

No I haven't overlooked the LEAS system. Now I am playing devils advocate here, but as you pointed out earlier your motion sensor is not proven by the self check system, so even though the self check gives a thumbs up, if the sensor were faulty such that it could not respond to motion, then the LEAS is giving you a false positive.

My conclusion to this quest; it seems that we have no way of conclusively checking the correct operation of these stability devices, without either deliberately driving in a way to cause them to activate, or taking special actions to verify their operation.

 

[Lutz]

John, as I pointed out in an earlier reply, the same applies to other safety systems. For example, there is no way of knowing whether the air bags will deploy correctly when called upon to do so.
Also, do you regularly check to see whether the ABS and/or ESP on your car is functioning properly? I rather suspect that you take them for granted, too.

 

[Dustydog]

Hello John,

I have no doubts that these caravan stability systems do make a significant contribution to the safety of towing, and as such I encourage caravanner's to consider fitting them, along with shock absorbers etc.

My concern is not with how they work, but more to how can you be sure they are ready to work when you start a journey. Unlike normal brakes and lights etc, there is no instant feedback.

At the risk of over labouring the point, indicator lights can and do sometimes fail to give the correct indication. I have seen (and condemned) on domestic and industrial controls where apparently they show a system is working satisfactorily, yet by other means can easily be seen to be faulty or potentially dangerous.

Basically a green light glowing may just prove the green light bulb is working, it doesn't necessarily prove the system behind the light is working. even if the system goes through an activation cycle when it is turned on, it is not actually responding to a motion sensors input, but a simulated signal. It is possible the motion sensor may be faulty.

From the other replies it seems there is no simple test you can do to confirm the actual operation of these systems, so you have to have faith in the design of the system, and can only report they have activated once you have strayed outside their detection envelope.

I am not trying to discourage caravanner's from fitting these devices, but until they have a situation where the system should respond, they wont know whether it really can respond.

Hi John
Unfortunately whilst most modern day systems strive to be "fail safe" the efficacy of any system cannot be guaranteed. You may get a green light in the cockpit but does that prove the undercarriage is lowered and locked? I have the ATC and it does go through a full test cycle. I have to assume the makers components are of good quality and will fail whilst going through the test cycle rather than on the road.
To me it's like the match. Will it light when struck??
Brake failure is not that common now but how many actually do the static brake test before each journey??

 

[John_374564913]

Dear Chris

i would appreciate it very much if you could let me know how to clear the memory as when I travel abroad I go on long trips and the last thing I want is to be without the ATC due to a full memory.
I am sure the forum moderator will give you my e-mail address or you can post it on the forum

Many thanks

John

 

[chrisbee1]

Hi John. I was advised by ALKO that all that is required is to power the ATC for at least 12 hours without it operating. They recommended plugging the S7 socket in overnight and assured me that the car battery would not drain due to the very small current draw of the ATC when in standby mode.

 

[John_374564913]

Dear Chris
Thanks for the information as I usually connect the car to the caravan the night before we leave this should give ample time for the system to reset so thank you once again

John

 

[Brian_374582181]

Hi All,

Well after the Caravan show last week, I booked for the alko atc to be fitted on Monday. Saved a little bit by having a mobile fitting from CMI. Will be trying it out the following weekend all being well

 

[mjt]

Hello all.
Today is the first time I have picked up this thread so I apologise for this late contribution relating my own bad experience. I will keep it as short as possible.
In Jan 2009 I took delivery of a new Lunar Lexon SB (2 fixed single beds at rear) fitted with ALKO AKS stabiliser and ATC anti snaking device. My tow car was a 2008 Kia Sorento (my 2nd , having owned one since 2004). My wife and I set off on the Lunar’s maiden journey Mar. 2009. This trip ended abruptly after 40miles when we got into an uncontrollable ‘snake’ causing the outfit to jack-knife into the M11 central barrier.
The result was not quite as dramatic as Brian’s experience but nevertheless both car and caravan were written off.
I was in a procession of HGV’s in lane1 of the 3-lane m’way approaching a junction where lane 1 branched left and 2 lanes went ahead so I had to change lanes into lane2 to go straight ahead whereas the HGV’s continued in lane1 to branch left. The transition to lane2 was smooth but after I had passed the first HGV, at 50/55mph, the snaking started. My reaction was to lift off the accelerator to allow the outfit to slow naturally. There was a moderate crosswind from the left that we had been subjected to for the previous 15miles without problem. It was my first theory that passing the HGV gave shelter followed by a gust which affected the stability of the caravan – exactly what the ATC is supposed to control!
My second theory was that the ATC itself caused the problem by some malfunction or, thirdly, did the Lexon SB have an inherently unstable design?
It seemed to me that the ATC did nothing to control this in the way it is demonstrated on ALKO website videos.
I have been caravanning now for 30yrs with only the occasional ‘twitch’ (I have always had a stabiliser of one sort or another). It is ironic that this happened with all the latest technology installed!
I have always taken great care regarding loading, noseweight and payload (to the extent that I use a baggage scale to weigh every item carried in the van) and I know that I was carrying the max payload. The Caravan Club state that the NW should be 5-7% of the van ALW which, in this case, would be 71-99kgs. The actual NW was 85kgs. Lunar state the min NW to be 50kgs. The van/car weight ratio was 68%.
I emailed Lunar & ALKO next day, Lunar were quick to pass it on to ALKO who, I have to say, were quick to respond and carried out a very thorough examination of the van and the ATC at the recovery yard. The ATC was removed and tested in the UK and then sent to Germany for further tests. To cut a very long story short, ALKO produced a very comprehensive report which was summarised as follows:-
"It is our opinion that external forces caused either the tow car or the caravan to swing so violently that the ATC system was unable to bring the swing under control before the coupled vehicles jack knifed."
"The tow vehicle exhibited a completely deflated nearside rear tyre.....it was not evident what caused this........a blowout or puncture scenario are possibilities." (I am totally confident that the tyre only deflated due to severe stress of being pushed sideways during the jacknife)
“Whilst it can not be concluded as to whether there was one or more contributory factors which caused the incident – tyre blowout, uneven or over loading of caravan, strong gusts of wind when passing lorries for example – it is confirmed that the ATC unit was, and still is working correctly”.

That answer doesn't exactly fill me with confidence!!
They did also raise one interesting point that is of concern. They weighed the Lexon at the recovery yard – it was 1419kgs. This is 6kgs above it’s MTPLM! They also noted that the van was virtually devoid of all possessions which they backed up with photographic evidence in their report. This was indeed true because, being so close to home, I was able to arrange a man-with-van at the same time as we were rescued from the yard. This throws serious doubt on the weights published by Lunar.
I have sought answers from Lunar, including writing direct to their MD Mr. Brian Mellor but to this day they choose to remain silent!

Moral – Don’t believe all you read about ATC’s or Lunar weights (use a weighbridge as also recommended by the Caravan Club).

To finalise, both my insurers paid out for new replacements so I am now on my third Sorento and our caravan is now a Swift 480 and yes, I did have an ATC fitted – just in case!

 

[Lutz]

Of course, based on the details given above, it is impossible to make conclusive judgment on why the snake was not controlled by the ATC unit despite it apparently functioning correctly when tested afterwards. The fact that no mention is made that any tugging of the caravan was felt as the ATC deploys suggests that it wasn't working when it should. Maybe there was an interruption of the power supply to the unit. This could account for a perfectly serviceable unit not working properly, but that's only a guess. Another more likely theory is that it or the brakes weren't adjusted properly at the time or the brakes had been subjected to fade immediately prior to the incident. As the ATC was removed for checking by AlKo, nobody at AlKo would be able to diagnose this as a potential cause.
I wouldn't wish to criticise the design of the ATC for lacking an important feature, but the LEAS system, which works on the same principle, includes a warning buzzer inside the towcar which notifies the driver when the system has deployed, thus keeping the driver informed all the time about its operation. There is also an additional feature available as a hang-on option which provides warning by the same buzzer if the brake shoes on the caravan have been subjected to fade.

 

[ProfJohnL]

Hello mjt,

It is a sorry tale you write, and I very glad that there were no injuries.

The element that does intrigue and concern me most though is your comment regarding the weight of the caravan

Quote
"They weighed the Lexon at the recovery yard – it was 1419kgs. This is 6kgs above it’s MTPLM! They also noted that the van was virtually devoid of all possessions"

This raises two possibilities, firstly that the scales used may have been inaccurate, or that the caravan was weighed incorrectly,

If you have removed quite a lot of stuff, then clearly the system was actually overloaded when being towed and that would definitely contribute towards instability.

But if as you say it was virtually devoid, then it means that some of the pay-load was still present. what items had been left in the caravan, for example
Were the gas bottles and battery left?
Food in the fridge and lockers?
Bedding, pots and pans?
Water in tanks and containers?
caravan Mover?

All these things soak up pay load capacity.

 

[Dustydog]

Hi mjt
What a scary experience for you and SWMBO.
I'm intrigued and now concerned about my Al-ko stabiliser and ATC.
Causation is clearly a hard one but from what you say weight now seems to be a distinct possibility.
You said the n/s tyre was totaly defltated. Again I wonder if this may have happened before the start of the upset?
Bearing in mind the weight of the Sorento and all your own weight checks, on paper I would have said the whole outfit looked very stable.
I'm no expert but even in a full sideways skid t it is unusual for a tyre to pull off the rim? I don't know.
I've been using the ATC for three years now and have never been aware of it actually operating. But then should I feel something??