Peter wrote:
Interesting. I wonder if they verified this in EMC lab testing, or just did what most in this business do and implement what seems a good idea – like e.g. Socata did on various occassions e.g. this and this where totally useless solutions were implemented. Most EMC solutions are meaningless without verification, because it is such a nebulous business. EMC testing of this system would be nontrivial, and I bet it was never done in the first place.Also, not being an AD…..
Why should it be an AD? Assuming the same freak conditions occurred in cruise, the parachute has proven to withstand speeds close to VNE, above that the chute will break away without damaging the frame. Also, as a mandatory safety bulletin, they can pass the onus onto the aircraft owner to make the modification – i.e. if the same instance happens again and you haven’t done this SB, tough, your liability.
I think the blame for lack of testing shouldn’t be given to Cirrus but more to BRS – after all, it was them who suggested / recommended the move to electronic ignition, Cirrus, as a system customer, believed that BRS had done their homework…. The fact that it was investigated and resolved pretty quickly is admirable.
Interesting. I wonder if they verified this in EMC lab testing, or just did what most in this business do and implement what seems a good idea – like e.g. Socata did on various occassions e.g. this and this where totally useless solutions were implemented. Most EMC solutions are meaningless without verification, because it is such a nebulous business. EMC testing of this system would be nontrivial, and I bet it was never done in the first place.
Also, not being an AD…..
Seems like a problem very well handled. The SB instructions are detailed, only 3 months after one isolated incident.
Peter wrote:
There has been surprisingly little “out” on this event, considering the massive implications which a chute activation via nearby lightning would have.How does the type of ignition affect it?
SB2X-95-24 was released in order to eliminate the risk of ‘atmospheric conditions’ causing the chute to be activated. The original rocket ignition installed to early Cirrus aircraft was performed mechanically – the pilot pulled on the handle which then moved an ignitor. The latest system uses an electronic signal which initiates the ignition. They have found that the shelf needs earthing otherwise static events can cause the system to interpret receiving the signal to ignite the rocket….
There has been surprisingly little “out” on this event, considering the massive implications which a chute activation via nearby lightning would have.
How does the type of ignition affect it?
The two larger pieces of rear fuselage contained part of the channel that enclosed the aircraft parachute straps. The cover panels were also found and appeared to have detached from the forward end rearwards, suggesting they were detached by disruption due to the impact rather than by deployment of the emergency parachute. From the aib report.
There is other evidence as well which it would be inappropriate to publish.
(Sorry to drift, but just to correct the record)
achimha wrote:
Did this Cirrus have the old style or new style ignition?
It had the new style electronic ignition. But apparently, the plane wasn’t directly struck by lightning, there are no ingress or egress marks. But there were thunderstorms nearby.
They never salvaged the N147KA wreckage so they can’t tell how it was activated.
The assumption lives on, until something unusual happens and evidence survives which disproves it..
Peter wrote:
It shouldn’t, but you never know.
The SR22 which crashed near the UK into the sea a few years ago had its chute deployed. Search for N147KA e.g. here.
There is good evidence the shoot was not deployed for this reason.
I would not be surprised if a future Cirrus generation comes with an improved wire mesh where the chute rocket is. This is not good and should not have happened.
Did this Cirrus have the old style or new style ignition?
