Medical Factors in Aviation Mishaps
By Dr. Susan Northrup, FAA Federal Air Surgeon
Fortunately, medical issues are not the cause of most aviation accidents. Nonetheless, even one is a tragedy. In this article, I will review some of the more common medical issues that have either caused or contributed to a fatal aviation accident.
You might be surprised to know that, by law, an autopsy is performed on occupants of all fatal civil aviation accidents, including passengers. This is usually accomplished by the local coroner’s office with assistance from the National Transportation Safety Board (NTSB) and Civil Aviation Medical Institute (CAMI). The latter is part of the FAA’s Office of Aerospace Medicine (OAM) and performs the toxicological evaluation of the remains, when feasible. You might wonder, though, why autopsies are required and what has been found.
There is simply no good reason to fly after taking a sedating medication, alcohol, or an illicit drug.
Several years ago, the OAM sponsored a study looking at fatal mishaps to evaluate for contributory medical issues (see the technical report). The author reviewed data from both the NTSB and FAA for a 36 month period beginning in April 2013. In the report, he laid out the three primary reasons for a post-mortem evaluation: 1) to help determine the probable cause of the accident; 2) to help reconstruct the accident; and 3) for injury analysis in order to better protect aircraft occupants in future accidents.
The author then looked at the records of 601 pilots involved in a fatal accident between April 2013 and March 2016. Over 40% had incidental medical findings (IMFs), which are medical conditions not previously known by the FAA, but discovered on autopsy. The NTSB determined that for this group of pilots, the most common medical issues, that were either causal or contributory, were use of a sedating medication, followed by alcohol or illicit drug use, cardiovascular disease, neuropsychiatric problems, and strokes.
A separate study showed that, of the impairing over-the-counter medications, diphenhydramine remains the most frequent culprit, found in almost 6% of the pilots who were involved in a fatal accident and for whom toxicology was available. Yet another study found that 15% of pilots in fatal accidents had controlled drugs and over 25% had potentially impairing drugs in their system; often these are taken for a medical condition that is itself impairing.
So what does this mean to you? First, the good news: the general aviation accident rate has steadily decreased over the past decade and the trend remains favorable. However, as a group, we pilots continue to make the same mistakes that lead to accidents. There is simply no good reason to fly after taking a sedating medication, alcohol, or an illicit drug. The attendant cognitive impairment will affect the planning process, go/no-go decision, and en route decisions. The ability to successfully handle an emergency is compromised. These problems are rare in airline and military pilots; both groups have strong safety cultures; we general aviation pilots should strive to emulate this.
What about cardiac disease, which is the most common cause of death in the adult population? With the right lifestyle changes and the proper medical management of risk factors, you can reduce the likelihood of medical incapacitation and extend the years that you are able to enjoy piloting an aircraft. These steps also make it easier to maintain medical certification and is safer for all whether flying under a medical certificate, BasicMed, sport pilot, glider, or ultralight.
Dr. Susan Northrup received a bachelor’s degree in chemistry, a medical degree from The Ohio State University, and a master’s degree in public health from the University of Texas. She is double board-certified by the American Board of Preventive Medicine in Aerospace Medicine and Occupational Medicine. She is a retired U.S. Air Force colonel and a former regional medical director for Delta Air Lines. She is also an active private pilot.