THE vital parts missing from an Army physiotherapist's "sabotaged" parachute have never before failed in a reserve chute, the attempted murder trial of her husband has been told.

Emile Cilliers, a sergeant with the Royal Army Physical Training Corps, is on trial at Winchester Crown Court for two charges of attempting to murder his former Army officer wife, Victoria Cilliers, on Easter Sunday, April 5, 2015.

The 37-year-old is also accused of a third charge of damaging a gas valve at their home a few days earlier in the second allegation that he attempted to kill his 40-year-old wife. He denies all three charges.

The prosecution says Cilliers tampered with his wife's parachute on the day before her jump with the Army Parachute Association at Netheravon, Wiltshire.

It says he did this by twisting the lines on her main parachute and by sabotaging her reserve by removing two of the four slinks, a nylon strip which connects with the lines to the harness.

William "Rusty" Vest, customer service manager for Performance Designs (PD) Incorporated in Florida, USA, the company which produces the slinks used by the APA said thorough testing was carried out on the product and "the slinks never failed".

He said via video link: "We have a thorough quality control process in place. They have a very high breaking strength."

He added that if a slink had broken it would cause friction burns to the lines of the parachute.

He said: "From my experience and research, I would say if a PD slink had broken during a parachute deployment, then all tests and history state there would be associated line and riser damage as well."

He said he had seen photographs of Mrs Cilliers' reserve parachute, which had never been deployed before, and he had not seen any damage.

Mr Vest said that the company had supplied slinks for 75,000 sets of four slinks but had only had two reported failures involving main parachutes.

He said that these two incidents happened when the parachutes were in poor condition and had not been well maintained and he added that they had not had any slinks fail in reserve parachutes, which he said were normally kept in "nearly-new or unused" condition.

Shahad Khawaja, who last packed the main parachute used by Mrs Cilliers on her near-fatal fall, told the court by video link from Abu Dhabi, UAE, that twists in a parachute line could be caused by a packing error, a problem with jumping or high winds.

She said that she had packed about 300 main parachutes by the time of Mrs Cillers' jump and had not had one malfunction before.

She said that she would have gone through a 22 stage process of packing the parachute on March 25, 2015, which would have taken her between eight and 10 minutes to complete as she was "not in a rush" that day.

She said that she did not believe she would have made a packing error to cause a twist as she ensured it would be neat before packing and use a technique to avoid twists.