The lift is located at the front of the profile: this causes the A and B lines to be heavily loaded, while the C and D lines carry very little weight.
Most often, the A and B lengthen, because the lift is located between the 2. Conversely, the C and D can even get shorter, because they are lightly loaded lines in normal flight.
We often find now that the As stretch much more than the B, proof that the lift is located further forward on the profiles of recent paragliders.
Production tolerances affect timing accuracy, as well as looser or tighter line connections.
Asymmetry can be caused by the pilot turning to one side more often than the other, especially in 360!
There are also cases of snagging in trees during a rocky landing where the lines had to be pulled to recover the wing… or any other particular event, such as a collapse with violent reopening… + wet lines which can shrink (this is due to the sheath!)…
The list of reasons that make the wedging move is long!
