I remember seeing the photos of this accident and was frankly very surprised that the airport had allowed this structure to stand - 'grandfathered' or not, when many airports have gone for fully frangible structures within the RESA. I'm not sure if the earth bank the MK 747 hit was actually within their RESA.
Definition of RESA - 'An area symmetrical about the extended runway centreline and adjacent to the end of the strip primarily intended to reduce the risk of damage to an aeroplane undershooting or overrunning the runway'.
There's lots more about the suitablity of the ground - can your fire appliances get across it - and the slope etc etc.
RESAs should be a minimum of 90 metres beyond the end of the runway and 'aids to navigation, which because of their function must be placed within a runway end safety area to meet air navigation requirements, should be constructed and sited to reduce the potential hazards to a minimum and consequential risks to an acceptable level'.
It is a pity that the system requires various injured parties to sue one another to receive compensation - a bit like each driver at a queue at the traffic lights has to sue the driver behind until you get to the person at the back who has actually caused the accident.
Perhaps they should be suing the FAA for giving the aerodrome a licence to operate with this clearly non-frangible structure? Does it work like that in the US?
If you REALLY need this sort of structure, then the only answer, in my view, is to reduce your declared distances until you can create a proper safety area in front of your first non-frangible obstruction. Then, of course, you're going to lose traffic and revenue. In which case, the cheapest option, in the end, is to remove your obstructions. It just doesn't seem like it before you have the more expensive accident...
Cheers,
The Odd One