I spent my life in engineering shops, usually in management positions. Every one of those shops made applicants take a battery of tests that included IQ tests. What we learned was that applicants who scored well on the IQ tests performed well on the job. Those with lower IQ scores who were hired because they scored well on the aptitude tests always performed poorly on the job.
IQ is an excellent indicator of performance in technical fields. It doesn't matter the race of the person tested, the ones who score high on IQ tests out perform the ones who scored average or lower.