This is the heart of the problem of remote controlled towing!
This very small risk must not be neglected. Electronics and software can fail, a servomotor can also have an internal failure that would make its motion uncontrollable.This technological command chain is like the winchman's hand. A winchman is rarely heavy-handed and when it happens he realizes it quickly...
So we had to limit these risks and the consequences as much as possible.
To go through all the securities available with Aviawinch, let's imagine a very bad scenario possible when several failures add further to a lack of appropriate reactions from the pilot...
You are on the ground, tied to the line, ready to take off, the engine is running, the pre-tension is over.
You have just enabled the level two of "TCS" (patented Tension Control System) to start the taking off stage. Suddenly the servomotor of acceleration fails and tension starts pulling you...
Several securities then come into play...
1 - The problem obviously comes from the servomotor itself due to an electrical or mechanical malfunction, therefore the software part of ACS (patented Acceleration Control System) that limits the displacement speed of the servomotor does not work.
2 - The mechanical part of ACS in the form of independent hydraulic cylinder fortunately reacts and mechanically limits the brutal acceleration which becomes progressive but, for all that, does not stop...
3 - The software part of the TCS could have stopped the tension when finding, through a position sensor, that the servomotor is not on zero as it should be because you did not press the acceleration trigger.
Bad luck, surprised by the unexpected starting of the tension you have clutched the acceleration trigger tensely...
Finally you release the acceleration trigger.. but surprinsingly the tension doesn't stop... To crown it all, this software part of the TCS has just broken down... bad scenario, you had been warned!
The TCS has also a mechanical part, not affected by electronics failure, that remains active and controls the tension effect by limiting it to its maximum tension of the taking off stage, that is to say around 40 kg (parametrizable for tandem flight).
4 - During this first second of inadvertent tension, you could have thought of releasing with one finger but you forgot...
5 - you could also have thought of using a finger of the other hand to switch off the engine by pressing a very easily reachable button on one of the handles. The command would have been transmitted by the two transmitters but you didn't think of that either...
6 - Really it is not your day... another second has gone by and with this 40 kg tension you stumble, the wing in a jumble behind you... Now your brain tells you to release and switch off the engine, you even remember that you have a red handle easily reachable on the shoulder to cut the line, switch off the engine and even release (all that in one single move!) but ...you remain passive...
7 - On the third second following the beginning of the incident, sensing that the integrity button placed on one of the handles has not been pressed and after setting off its new alarm, the HCS (patented Human reaction Control System) activates the stopping of the engine... You are a bit groggy but you're ok...
6bis - Let'go back at the end of step 5.
With this 40 kg tension, your well-positioned wing has got filled out and you have now left the ground. You are progressively getting higher... You think that after all you fly, you were ready for that...
7bis - Two seconds have now elapsed since the beginning of the incident... You think it would be better to regain control... you finally press the stop button... Nothing happens... Really it is not your day: a malfunction of some element in the chain of commands has occurred...
On the third second following the beginning of the incident, you finally think to simply release with just one finger...
At the same time, with no integrity information from you, the HCS activates the stopping of the engine... You are 10 metres high, you get down and land right in front of you... All is fine...
8 - You take a deep breath thinking it could have been worse without all those redundant securities that activate themselves. You also realize that you have not been the best "captain" possible...
You contact us annoyed about these malfunctions but at the same time grateful for this big work on security. You legitimately ask us to activate the warranty. That will not stop you, considering the incredible liberty that Aviawinch gives you!