Title not stated in source · Converted to 42399, effective April 30, 1977
Exact dated 9-skill-level code change; the predecessor's specific title is not stated. Verified source wording: “The 9-skill level designation was changed from AFSC 42393 to AFSC 42399 on 30 April 1977.”
Sources
- Aircraft Fuel Systems Career Ladder. (Internet Archive full-text OCR around char offset 6,988; governing lineage context verified)