It's disheartening to see that a supposedly highly qualified engineer signed off on the manufacture of replacement tie rods, without going through all the engineering modifications/accident history associated with the design.
It's also disturbing to see that an authorised and reputedly competent engineering company, producing replacement aviation components, apparently took it upon themselves to replace the specified high-tensile carbon steel rod, with stainless steel rod of lower tensile strength and of variable specification, for the manufacture of the replacement tie rods.
It is even more disturbing that the threads installed on the replacement rods showed a wide variety of finish quality, with some threads appearing to be hand cut. Even some of the lathe-finished threads were of dubious finish.
In a high stress component such as the tie rods, surface finish is critical to prevent the initiation and propagation of cracking.
The fact that the tie rods in the accident aircraft were cracked through up to 60% of their thickness - and that this cracking was never found - is dreadfully disturbing, and virtually complete and utter negligence.
I can understand the engineering company suggesting a change to stainless steel because some previous tie rods produced, that had been in use, showed signs of serious corrosion.
However, to change the steel type without any reference to any aviation authority, and gaining official approval, shows a poor understanding of aviation engineering and processes - and even poorer supervision and quality control processes.
This accident shows up a pretty cavalier approach on the part of numerous personnel involved in the ownership, repair, and operating of this aircraft, towards maintenance, towards aviation replacements engineering, and towards record-keeping.
It does not reflect at all well on anyone associated with overseeing the Moth repair, the maintenance, the modifications, the quality control, and the adherence to strict and well-defined aviation principles, in a number of areas - and I personally feel the lawyers are bound to have a field day here, such are the major deficiencies discovered in the investigation.
It behoves anyone operating an aircraft well beyond its original projected lifespan, to ensure that engineering modification information and accident history is complete, up-to date, and properly recorded - and that maintenance and repair is of the highest level, to ensure any chance of disaster is reduced to the bare minimum.
To be additionally carrying out aerobatics in an aircraft well beyond any projected lifespan - and carrying members of the public as well - means that the requirements listed in the paragraph above must be above reproach.
The investigation has revealed such major shortfalls in the operation of the accident aircraft, that one could only properly describe it as a "cowboy outfit".