Light aircraft manufacturer Cirrus Design will pay to modify critical hardware on the Cirrus Airframe Parachute System installed on 3,300 in-service SR20 and SR22 piston singles.

The announcement comes two months after a serious SR22 accident in Australia revealed shortcomings with the mechanism that connects the parachute to the deployment rocket. After investigating, the company on 29 March issued a mandatory service bulletin calling for all owners to change out the system's pick-up collar within the next 25 flight hours. The system uses a rocket that fires through a pick-up collar, mounted to the launch tube and connected to the canopy of the parachute. The parachute deploys when a lip at the bottom of the rocket captures the collar at the top of the launch tube.

In the 5 February accident near Sydney, the pilot and passenger of an SR22 experienced an engine failure and tried to land on a highway. They instead deployed the aircraft parachute system when it became clear there was too much traffic on the road, says Dale Klapmeier, Cirrus Design executive vice-president and co-founder. The parachute failed to deploy correctly because the rocket was unbalanced and did "not fire straight", he says. The pilot then made a forced landing next to the highway.

The US National Transportation Safety Board reports that the pilot and passenger were seriously injured in the accident and that the aircraft was "substantially" damaged. The Australian Transport Safety Bureau had not issued a report as of last week.

According to Klapmeier, engineers at Cirrus and Ballistic Recovery Systems, the contractor that builds the parachute system, determined from scratches on the recovered rocket that the pick-up collar had been misaligned, causing it to slide too slowly down the shaft of the rocket after launch. The likely cause of the misalignment is that the plastic screws holding the collar in place on the launch tube had broken free when the rocket ignited, rather than holding fast until the flange at the bottom of the rocket passed by. The new collar uses aluminium screws and is designed to stay in place even if the screws break free too early.

Klapmeier did not say how much the fixes will cost the company, which will have at least one mechanic in each of its 145 service centres trained by this week to change out the suspect hardware.

Source: Flight International