I think there is a need to recalibrate expectations of crashworthiness 
A typical GA light SEP has the crashworthiness of one of these
and not one of these
It does however have software which doesn’t cheat on the emissions like the one above 
LeSving wrote:
Clearly something is very wrong IMO
Actually the spar behaves just as it should. There was a tremendous impact with the helicopter that allone lead to a substantial damage of the wing and high stresses at the wing root.
mh wrote:
Actually the spar behaves just as it should. There was a tremendous impact with the helicopter that allone lead to a substantial damage of the wing and high stresses at the wing root.
The impact torn off about 1 m of the wing tip, but the aircraft itself didn’t yaw an inch. That is odd. IMO, what is shown on the video below is a factor. The forward attach didn’t work as it should due to ovalisation, and judging by other videos in this thread, it’s not a one off. Instead of yawing the aircraft, all the energy went to bending and weakening the spar. The other option is that the impact, despite the damage, wasn’t very strong in terms of forces. Thin aluminium plates and plastic against a compact helicopter engine is hardly a fair fight. But that last option doesn’t really explain why the spar broke like it was made of paper IMO.
At 5m52s
Hmm, there seems to be a bug when copying a youtube video with a starting time. It ends up with a + in front, and no video, only the url text.
It will be really interesting to read the full report of this last accident.
Actually I’m not sure what I like less: the first problem when the wing gets destroyed so easily by the Robbies back rotor housing, the second problem when the wing snaps off on impact, or the third event when the other wing also breaks after impact on ground.
I mean, seriously ?
These planes are not built the same as IFR tourers selling for 2x to 3x the price.
The advantage is that if you have to do a forced landing into a forest, pick a gap between some trees, and the wings with all the fuel in them will be cleanly removed.
This is not wholly tongue in cheek. If you google for N403HP (another Piper albeit a rather more expensive one) and dig out the photos of the wreckage, you will see the wings came right off. That pilot unfortunately did not survive, due to banging his head on something. But there was no fire, despite a large fuel spillage.
I can’t currently find a reference, but I remember reading that wooden glider wings differed from wings for powered aircraft in that they needed extra diagonal bracing (as seen from above) to cope with the forwards acceleration encountered on bungee launches. Wings for powered aircraft need to deal with large vertical forces, but there’s no reason for them to be able to resist significant forces in the aft direction.
The in flight aerodynamic drag loads on any wing are a side effect of developing lift, and are actually quite significant. They absorb much of the engines power. I believe on a stressed skin wing like the Cherokee’s the drag load is carried to the root by shear in the skins, which is then reacted by differential tension/compression between the two spars, not bending of the spars. The loading at the wing root is therefore completely different than for lift loads.
Obviously any drag load at the tip has about twice the moment arm of an in flight lift or drag load. One guess is that failure due to a physical load at the tip might result from buckling of the skins under the drag component of the load. Buckling failure results from instability versus over stress, meaning it happens fast. The spars then snap when they are subsequently forced to carry bending in an unintended direction, instead of differential tension/compression, and the wing folds in whatever direction its being pushed. The bolted attachment of the wings to the fuselage wouldn’t be relevant to this failure mode.
EuroFlyer wrote:
I mean, seriously ?
You DO realize, that aircraft structures are lightweight design and not built to resist impacts with solid objects at over 50 m/s? With this speed, cars would have much trouble, too.
Good news, my PA28-181 just passed it’s NDT bolthole testing with absolutely no problems, we removed just the bottom outer 2 bolts on each wing spar and sent in a magnetic resonance bolt hole tester.
So you can compare your PA28 , mine is as follows:-
I’d guess it has been used far more than an average PA28 which is probably reassuring to others. The accident aircraft was a Arrow however, so perhaps the extra weight of the retractable gear made a difference. Arrow owners will probably have to keep an eye out for the NTSB updates.
That’s very good news. Probably not unexpected, but it’s better to be sure
