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.
Causes of rheumatoid arthritis. Rheumatoid arthritis is an autoimmune condition, which means it is caused by the bodyâs immune system attacking itself. However, it is not yet known what triggers this.Normally, your immune system makes antibodies that attack bacteria and viruses, helping fight infection.auses of rheumatoid arthritis. Rheumatoid arthritis is an autoimmune condition, which means it is caused by the bodyâs immune system attacking itself. However, it is not yet known what triggers this.