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.
Researchers are working to understand what causes rheumatoid arthritis. Rheumatoid arthritis (RA) is a complex disease in which the patientâs immune system attacks its own tissue causing swelling and inflammation in the joints and damage of tissues and other organs.uch of the rheumatoid arthritis research being conducted focuses on immune mechanisms involved. Many of these mechanisms are shared with other autoimmune diseases that attack different organs, such as lupus (kidneys), multiple sclerosis (brain) and Type I diabetes (pancreas).