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A manufacturing mistake which makes it into service is a failure of QA and testing systems design. (At least above a certain threshold which varies depending on

by mastax 3y ago

A manufacturing mistake which makes it into service is a failure of QA and testing systems design. (At least above a certain threshold which varies depending on the industry etc. etc.)

derefr 3y ago
Depends. You can’t do e.g. crystallographical analysis of metals inside an engine if the engine is already put together. You have to trust your vendor that they built the engine correctly and checked the materials themselves. Or at most send auditors to the vendor.
- krisoft 3y ago
  > You can’t do e.g. crystallographical analysis of metals inside an engine if the engine is already put together. QA is not forced to only deal with assembled components. They can be embeded before the assembly process to QA the parts. For example they could peform crystallographical analysis on a subset of blades which are ready for assembly. They can also take apart a certain percentage of randomly selected engines, perform crystallographical analysis on a subset of parts and then re-assemble the engines. Many options.
  - plorg 3y ago
    Titanium fan disks, for example are all required to be inspected not just when installed but also at regular engine maintenance intervals. The inspection requires essentially complete disassembly of the fan (so it is required during particular engine maintenance events) followed by the application of penetrating dye and inspection at a narrow granularity. This kind of maintenance and inspection actually can be required and performed, it just costs more time and money. If we want to be all market capitalism about this we could require tests necessary to ensure safety and let engineers, business people, and executives make decisions that price in the cost of dangerous and risky designs that require constant and invasive inspection and maintenance. The only real difference with today would be regulators having a spine and/or more than pro forma power to enforce their decisions.

by mastax 3y ago

A manufacturing mistake which makes it into service is a failure of QA and testing systems design. (At least above a certain threshold which varies depending on the industry etc. etc.)

derefr 3y ago

Depends. You can’t do e.g. crystallographical analysis of metals inside an engine if the engine is already put together. You have to trust your vendor that they built the engine correctly and checked the materials themselves. Or at most send auditors to the vendor.

krisoft 3y ago
> You can’t do e.g. crystallographical analysis of metals inside an engine if the engine is already put together. QA is not forced to only deal with assembled components. They can be embeded before the assembly process to QA the parts. For example they could peform crystallographical analysis on a subset of blades which are ready for assembly. They can also take apart a certain percentage of randomly selected engines, perform crystallographical analysis on a subset of parts and then re-assemble the engines. Many options.
- plorg 3y ago
  Titanium fan disks, for example are all required to be inspected not just when installed but also at regular engine maintenance intervals. The inspection requires essentially complete disassembly of the fan (so it is required during particular engine maintenance events) followed by the application of penetrating dye and inspection at a narrow granularity. This kind of maintenance and inspection actually can be required and performed, it just costs more time and money. If we want to be all market capitalism about this we could require tests necessary to ensure safety and let engineers, business people, and executives make decisions that price in the cost of dangerous and risky designs that require constant and invasive inspection and maintenance. The only real difference with today would be regulators having a spine and/or more than pro forma power to enforce their decisions.