Flying With Type 1 Diabetes as Commercial Airline Pilots in the U.S.: The Sky Is the Limit for People With Type 1 Diabetes

Historically, type 1 diabetes was a disqualifying condition for the medical certification required by the Federal Aviation Administration (FAA). Until recently, pilots with insulin-treated diabetes were not eligible for first- and second-class medical certificates required for commercial flights in the U.S. With the advancements in continuous glucose monitoring (CGM) and insulin therapies in the last decade, the FAA made an important policy shift in November 2019, announcing that pilots with insulin-treated diabetes can apply for these medical certificates under strict criteria.

Pilots must undergo a comprehensive evaluation for medical certification and show strict glycemic management. For the initial certification, a pilot must see a board-certified endocrinologist, use FDA-approved real-time CGMs for >6 months, collect laboratory tests, and obtain comprehensive eye and cardiac risk evaluations (1) (Table 1). For the initial assessment, FAA requires a detailed progress note from the endocrinologists and CGM reports monthly, showing ambulatory glucose profile, alert settings, and weekly overlays/graphs for each week of the month (1). FAA also requires strict criteria for CGM use and its metrics (Table 1). Weekly graphs/overlays must demonstrate consistent glycemic control with minimal excursions. After the initial evaluation, certified pilots must submit their follow-up documents regularly to renew their certificates. They must see an endocrinologist every 3 months and submit their detailed clinical progress notes and monthly CGM reports every 6 months to the FAA (2). They must also repeat laboratory tests and eye and cardiac evaluations annually (2). Here, we report on six commercial pilots with type 1 diabetes and their glycemic management for 12 months.

At the Barbara Davis Center for Diabetes Adult Clinic, we initiated class I medical certification for the FAA for six pilots with type 1 diabetes to be qualified to fly as commercial airline pilots and followed them for 12 months. Median age was 35.3 years (range 22–49) and diabetes duration 14.3 years. All were male, and 84% were using an automated insulin delivery system. The average fly time was 24 h/week. Mean ± SD HbA_1c was 5.9% ± 0.1%, 6% ± 0.1%, 6.2% ± 0.5%, and 6.3% ± 0.5% at certification application and 3, 6, and 12 months after certification, respectively. Mean percent time spent with glucose in target range, 70–180 mg/dL, was 88% ± 5.5%, 88% ± 6.5%, 91.3% ± 4.5%, and 88.8% ± 6.1% at certification application and 3, 6, and 12 months after certification. Percent time spent with glucose <70 mg/dL was <2% at all time points. There had been no severe hypoglycemia events in 12 months. The pilots reported no adverse events related to diabetes during their flights.

This is the first observational study in the U.S. with commercial pilots with type 1 diabetes. The FAA requires frequent comprehensive evaluations, ensuring strict glycemic management without adverse events. Our results show that the FAA’s high standards can be achieved and sustained.

Our center shares several important responsibilities: 1) clinical progression notes should be structured and include all FAA-required information, so we suggest using a specific template; 2) monthly CGM and pump reports should be generated with all required information included; and 3) following FAA checklists thoroughly is crucial.

In an observational study, pilots with insulin-treated diabetes were asked to self-monitor blood glucose (SMBG) within 2 h before reporting for duty, within 30 min before takeoff, every hour while flying, and within 30 min before landing. Of the results, 97% were between 90 and 270 mg/dL, and this range was considered safe (3). However, with the recent advancements in diabetes technologies, as also seen in our study, stricter glycemic control is possible among commercial pilots without compromising hypoglycemia risk.

The small sample size was a limitation in this study, and most of the pilots in our study used an insulin pump. In a recent flight simulation study, the effect of atmospheric pressure changes on insulin pumps was evaluated (4). Full cartridges overdelivered 0.60 units of insulin during a 20-min ascent and underdelivered by 0.51 units during descent compared with ground-level performance (4). In the same study, pilots’ SMBG data were reviewed retrospectively and there were no episodes of hypoglycemia (4). Insulin pump–using pilots in our study did not report adverse events during flights. Ambient pressure reduction causes bubble formation and expansion within insulin cartridges, leading to the unintended delivery of small insulin doses independent of predetermined delivery rates (4). The FAA suggests clearing any bubbles in tubing seen with changes in cabin pressure and, in the event of sudden cabin depressurization, turning off or disconnecting the pump (5).

Many people with type 1 diabetes had to cancel their childhood dreams of flying until recently. Increasing advocacy for people with type 1 diabetes in parallel to advancements in diabetes technologies led to recent changes in aviation history. Flying with type 1 diabetes as a commercial airline pilot is now possible under strict regulations.