Aeromedical Risk: LSA, Basic Med, and 3rd Class Certificate

Medical Certification Reform

Aeromedical Risk – You don’t have to go far to find an opinion about the FAA and medical certification. AOPA and EAA, among others, spent a lot of time and energy to change the way pilots are medically certified. Adopted in 2004, the light sport rule was originally the most significant example. It allowed pilots with valid driver’s licenses, but no medical certificate, to fly airplanes with certain performance limitations. Bolstered by that success, AOPA and EAA soon started a campaign to allow a driver’s license to replace a medical certificate for the four-seat, 180-horsepower airplanes allowed for recreational pilots. 

While that request ultimately fell on deaf ears, their efforts eventually paid off in what we now know as Basic Med. It did not remove the requirement for a medical exam. An exam is still required every 4 years, but it does not have to be an AME; any state-licensed physician can perform the exam. The intention was that a pilot’s physician should be able to tell how healthy they are. However, there was no way to stipulate that your regular physician be the one who performs the exam. 

Basic Med

Basic Med did allow pilots without a medical certificate to fly some very capable airplanes. It allows for up to six place aircraft of no more than 6,000 pounds, up to 18,000 ft, IFR or VFR, not to exceed 250 knots, and can not fly for hire. There are some other rules to consider as well, but this is not a detailed article about Basic Med. On the whole, Basic Med is a great option for a lot of people. According to AOPA, nearly 80,000 pilots have used it. 

Aeromedical Risk

The FAA’s Aeromedical Certification Division (AMCD)’s primary job is to assess aeromedical risk. Their concern is for a sudden or insidious incapacitation resulting in loss of control of an aircraft. This can come from things like medical conditions, medications, or other medical treatments. While AMCD is staffed and run by physicians, these physicians are not your treating doctors. They are evaluating you for the privileges of the class for which you are applying and the duration for which it lasts. And, while your doctor may be very competent in their field, they likely know very little about aviation accident history and trends or how things can change in a thinner atmosphere and under the sensations of flight.

Blood Pressure

This is why the FAA will accept your blood pressure being higher than what your treating doctor will likely accept. That moderately high blood pressure is a long-term risk, but not likely to be the direct cause of incapacitation in the next 6-12 months. But it is also why the FAA will not accept chronic use of nerve pain medication when your doctor is perfectly comfortable with it. Nerve pain medication slows down signal processing in the brain which has the potential to impair cognitive function. At 1 G and 0 knots that may not be noticeable.

For a single pilot at 12,499 ft in night IMC conditions with an aircraft malfunction, it might be a significant contributing factor to an accident. Meanwhile, fatigue is a leading cause of aviation accidents so anything that could contribute to excessive fatigue will be disqualifying. That includes even seemingly innocuous medications like cetirizine or Zyrtec. 

Combination of Conditions

The FAA isn’t looking at your condition in isolation, but how the combination of conditions may impact each other and how the medications or other medical treatments may impact you. There is a difference between being treated after a heart attack and passing a stress test compared to an invasive procedure that confirms the arteries look good on the inside. This is why a Third Class does not require the invasive procedure, but a First Class does. That First Class allows for the possibility of flying around hundreds of your fellow humans inside of a weapon of mass destruction. Wait, a what?!?!

Understanding the Risk Difference

One of the opinions we frequently see is that the Third Class medical should go away. Basic Med has proven to be fairly safe. So why not replace the Third Class with Basic Med? Putting aside the fact that doing that would require yet another act of Congress, the physics are compelling. 

Upon impact with a house a car or airplane may be accelerating, but is more likely to be at a near-constant velocity. Force is mass times acceleration (F = ma). Momentum is mass times velocity (p = mv). The “energy” of an impact is easier to estimate based on the Momentum because determining Force will need to know how quickly the object in question stopped. Momentum is a good representative of the energy contained in a moving object.

The Physics of Near Constant Velocity

The gross weight of a 2023 Chevrolet Tahoe is about 7400 lbs. If one lost control in a neighborhood and veered off the road and impacted a home, a very high speed in that environment would be – at most – about 50 mph. It would probably slow down a bit as it hopped the curb and took out the fence and a few garden gnomes. Hopefully, the driver would hit the brakes too, or at least take their foot off the gas. But if they are unconscious they could have their foot on the floor.

p (Tahoe) = 7400 lbs x 50 mph = 542,490 lb-ft/second = 986 HP = 736 kW

The gross weight of a Bonanza A36 is approximately 3600 lbs. We could not find what the terminal velocity is for an A36. But an out-of-control Bonanza could be at or near Vne in a dive into a neighborhood, which is around 205 knots. 

p (A36) = 3600 lbs x 205 knots = 1,245,674 lb-ft/second = 2265 HP = 1689 kW

While the Tahoe weighs much more, the force it would likely impart in an accident is dwarfed by the much lighter, but significantly faster, Bonanza.

Mitigating Risks

Mitigating risk isn’t just about managing the common things. It is also about eliminating rare, but catastrophic things. An airliner crash has devastating consequences for those on board and for anyone on the ground. 9/11 effectively showed that airliners can be used as weapons of mass destruction. 

Whether or not you want to fly a 747, if you have a Third Class medical, you can legally fly any size aircraft you can get your hands on and be qualified to fly. You may not do so for compensation, but John Travolta has shown us that with enough money, a third-class medical certificate can go much further than most people think. While that may be an extreme example there are many wealthy individuals who fly owner-operated turboprops and business jets. 

Size, Mass, and Speed

As the size of the aircraft increases, not only does the mass increase, but generally so does the speed. And with both increased size and speed, the total possible energy dissipated on impact goes up significantly. And that can directly translate into a larger and larger catastrophe. Both Sport Pilot and Basic Med effectively cap that catastrophe with a weight and speed limits:

p (max Sport Pilot) = 1320 lbs x 120 knots = 248,871 lb-ft/second = 453 HP = 337 kW

p (max Basic Med) = 6000 lbs x 250 knots = 2,533,574 lb-ft/second = 42,606 HP = 3,436 kW

And this is only straight and level speed, not Vne or terminal velocity.

Sport Pilot has virtually no independent aeromedical risk analysis. Basic Med is not as stringent compared to a Third Class medical. There are less requirements and the physician certifying you possibly has no aviation training. Neither is there any secondary review by the FAA. As long as a Third Class medical lets a pilot fly virtually any aircraft they can afford, then it is entirely appropriate for that risk analysis to be more thorough.
# Aeromedical Risk