The applicability of FAR 121.377 is not eliminated by a person's performing a mix of work such as you describe. Such an interpretation would defeat the purpose of the regulation which is to insure that person's performing part 121 maintenance or preventive maintenance are provided relief from duty.
The cause of rheumatoid arthritis is unknown, although it appears to be an autoimmune disease. When the body's immune system does not operate as it should, white blood cells that normally attack bacteria or viruses attack healthy tissue instead â in this case, the synovium, or joint tissue.
What is rheumatoid arthritis? Rheumatoid arthritis is an autoimmune disorder that causes chronic inflammation of joints. Rheumatoid arthritis (RA) tends to begin slowly with minor symptoms that come and go, usually on both sides of the body, and progress over a period of weeks or months. Symptoms of this chronic disease vary from person to person and can change from day to day.