Flying meant everything to Arnold Greenwell, a research biologist living in Chapel Hill, North Carolina, when he received his private pilot certificate in December 1982. It still does.
Greenwell had no health problems, no family history of diabetes, or any sign of the disorder. But two years and about 120 flight hours later, his blood glucose levels began to rise. When diet and exercise could no longer control the condition and oral medication was prescribed, Greenwell voluntarily hung up his flying hat. (Diabetics controlled by oral medication were not considered for special issuance of medical certificates until the late 1980s.)
"It was devastating," he said. "I'd finally found something that I wanted to do, and I realized I wouldn't be able to [continue flying] because I wasn't able to maintain a third class medical certificate." Greenwell all but stopped hanging around the airport. "Losing your medical was always the kiss of death, as far as flying went."
Occasionally Greenwell would go flying with an instructor, and he found other ways to stay involved in aviation. "Aviation photography became very important to me — I refused to give up flying. I think about it daily."
On December 23, 1996, some insulin-dependent diabetics became eligible to be considered for special issuance of third class aviation medical certificates. This change in FAA policy is the culmination of more than 10 years of efforts by AOPA, the American Diabetes Association, and other concerned organizations and individuals. Greenwell, who now requires insulin, hopes to qualify for a medical certificate under the new provisions. "I've already talked to my doctor, and we're working to address it," he said.
There will not be a flood of insulin-taking diabetics who will meet the complex requirements, so the new regulation may not seem important to non- diabetic pilots. However, now that the FAA and Dr. Jon Jordan, the federal air surgeon, have taken this step, there is hope that advances in medicine will allow pilots with other currently disqualifying disorders to be considered for certification. Disease is now a factor in less than one percent of general aviation accidents, so it is unlikely that allowing a few carefully monitored diabetics — or any pilot with another well-controlled condition — into the air will substantially affect safety. Pilot skills and weather are much greater factors in flying safety.
Diabetes mellitus is caused by a failure of the pancreas to produce sufficient insulin, or failure of insulin to work. The hormone is secreted into the blood in appropriate quantities to control the level of blood glucose (sugar). This level must be tightly regulated to maintain the chemical balance in the body, and indeed to sustain life. Too little blood glucose and the brain starves; too much and the resultant chemical changes can lead to diabetic ketoacidosis, and even fatal coma. All diabetics, some of whom are more "brittle" than others, perform a balancing act between having too much insulin, resulting in insulin shock, and too little insulin, resulting in chemical imbalance.
Diabetes mellitus comes in two types. Childhood onset, or Type I, diabetes is caused by autoimmune destruction of beta cells in the pancreas that produce insulin. The condition is genetically predisposed and occurs before age 18; Type I diabetics are insulin dependent for the rest of their lives. Adult onset, or Type II, diabetics present a wider spectrum. Beginning at age 40 or older, they may have a partial failure to produce insulin or become resistant to the normal effects of the hormone. Some Type II diabetics control the disorder by losing weight, exercising, and restricting the intake of sweets. Others can be managed on oral medication, though some are severe enough to require daily insulin injections.
Diabetes unpredictably affects the body's organ systems, including eyes, kidneys, peripheral blood circulation, the nervous system, and the ability to ward off infections. Such secondary effects or complications occur gradually and seldom are the cause of sudden incapacitation, but they can be severe enough to prevent safe piloting. However, diabetics — especially those dependent on insulin — can experience rapid changes in mental acuity, including unconsciousness. This is why diabetes is one of 13 disqualifying illnesses, along with epilepsy, psychosis, angina, and myocardial infarction (heart attack). The only exception is diabetes that is controlled by diet, weight reduction, and exercise. Most diabetics were excluded from flying, and a few were forced to forgo better glucose control afforded by medication in an attempt to retain their right to fly.
Since the late 1980s, some diabetics on oral medications have been accepted for special issuance of medical certificates. In 1992, the FAA began on a test basis to certify insulin-treated air traffic control specialists, who must hold second class medical certificates. This program was a success, paving the way for consideration of diabetic pilots.
Insulin-treated diabetics will now be considered for special issuance, in part because of better supervision of their condition by physicians and better management by the diabetics themselves. Many diabetics routinely test their own blood glucose at home and adjust their insulin dosage, frequency of self- injections, and diet. This leads to better and safer management of the disorder, and the new regulations take this into consideration.
Pilots wishing authorization to fly while on insulin must document a history of stable diabetic management. They must be free of serious diabetic complications that could affect sight, heart, brain, kidneys, etc. Each diabetic applicant and his physicians need to review the regulation closely to determine how it applies (See "Steps to special issuance" above). Diabetics who receive special issuances must see their specialist for reexamination and glycated hemoglobin measurement every three months. Glycated hemoglobin assesses glucose control over the past 60 days, much like a flight recorder. While a diabetic may have a normal blood sugar at any given time, glycated hemoglobin allows long-term assessment of control.
Pilots must carefully document the course of their disorder, and take a series of blood glucose measurements before and hourly during each flight and within half an hour before landing. They will have to carry all the equipment necessary for testing, and sufficient glucose snacks to correct any hypoglycemia. Any adverse occurrence must be reported to the FAA.
Diabetics and their physicians will need assistance in negotiating the maze of regulations allowing special issuances and, once flying, in complying with the new regulations. The AOPA Medical Certification Department is as close as your telephone and is a good resource for help with both matters. Call 800/USA-AOPA.
Steps to Special Issuance
To qualify for the special issuance, applicants may have no otherwise disqualifying conditions, especially significant diabetes-related complications (arteriosclerotic coronary or cerebral disease, retinal disease, or chronic renal failure). Insulin-taking diabetics may be issued only a third class airman medical certificate for use with a student, recreational, or private pilot certificate.
Applicants may have had no more than one hypoglycemic reaction with loss of consciousness, seizure, impaired cognitive function which occurred without warning symptoms, or requiring intervention by another party within the past five years. One year of stability must follow the episode of hypoglycemia.
Maintenance of the special issuance requires complete reevaluation by a specialist every three months, and daily blood glucose measurements must be provided.
A digital glucose monitor with memory must be carried in flight, along with supplies to obtain and measure blood, and rapidly absorbable glucose in 10-gram portions. Pilots must document a blood glucose level of 100-300 mg/dl within one half hour prior to takeoff, hourly during flight, and within one half hour prior to landing.
A detailed summary of the regulation is available from AOPA's Medical Certification Department by calling 800/USA-AOPA, and from AOPA Online on CompuServe and the Internet (www.aopa.org).
Ian Blair Fries, M.D., is a senior aviation medical examiner who chairs the AOPA Medical Advisory Panel and sits on the AOPA Air Safety Foundation Board of Visitors. Gary E. Crump heads AOPA's Medical Certification Department — Ed.
