Pilot Medicals Demystified

Please remember that the content of this article is for general information only and should not be used as a substitute for proper medical advice. Or indeed entertainment.

Regular inspections 

Like so many of us, I have to organise a regular medical examination with a Designated Aviation Medical Examiner (DAME) in order to keep my pilot licence valid and to continue to be able to teach the intricacies of the art of flying to student pilots. 

A Class 1 medical examination must be done every year for my commercial qualification. While recent changes mean that I could instruct with a Class 2, I choose to retain the higher standard for the occasional stint of airwork. 

For private pilots of my age a less-demanding Class 2 medical is only required every two years. For private pilots lucky enough to be still under the age of 40 (apparently when the wheels start to fall off), every four years is enough. Of course, you already knew all the details contained in CASR 67.205 that spell this out. And of course, all the terms and conditions that you didn’t bother to read will still apply. 

I believe that the regular, enforced medical is a good thing. Without this necessary visit I doubt that I would see my doctor that regularly. I certainly would not get my blood taken at such regular intervals and be proactive enough to keep the numbers within limits.

What they look at

Before your appointment with the DAME, you will be asked to complete an extensive online questionnaire about your full medical history. Be prepared to provide details of every medical visit ever made to just about any type of practitioner. Fortunately, you only need to do this once, then it is updated just before each regular examination. 

The hearing test makes sure that I am not suffering from industrial deafness. I said, the hearing test… never mind. This reminds me of the importance of good headsets. When I first started taking flying lessons, my instructor did not use headsets. This made for slow progress with understanding the radio. These days when my students try to complain to me that they don’t understand the radio, I tell them this story, and remind them that for me the radio calls were in a second language. 

On the day there is also a urine test (drink plenty of water before you turn up), an ECG, checks for colour blindness, motor functions and cognitive functions. They will look at your responses to the online questions including your family medical history. You will also be sent for a blood test. 

Advice for beginners 

I always advise students who start learning to fly with me to initially go and get a Class 1 medical so that they know upfront whether or not they will be able to get a medical for their planned target level of qualification. 

It happened once to a student of mine that he was unable to get a Class 1 medical due to an existing condition. 

‘Be prepared to provide details of every medical visit ever made to just about any type of practitioner’

Unfortunately, that condition got worse over time to the point where he lost his Class 2 medical a couple of years after getting his private licence. Knowing from the outset that he was not able to get a Class 1 medical made us reconsider his training goals. In the end he was happy to become a pilot at whatever level he could. 

Not the end of the world 

When someone fails their medical – and I hate the way it sounds, but they call it an exam, therefore it is a pass or a fail – one of the options is to become friends with a private pilot with a current medical and use them as a safety pilot. That way you may continue to fly as normal, except that the other pilot will be the pilot in command. And your mate won’t be able to sit in the front seat. 

My own blood test results 

This year some of the numbers from the blood test were slightly elevated. For me the main issue was how do I bring these numbers into line? To stay healthy, do I need to rethink my eating habits? Do I need to exercise more often? 

For me this time around, I wanted to understand what each of the numbers meant. More importantly, why are some of these numbers now not within limits? Especially those that could keep me permanently grounded and stop me enjoying one of my great passions in life. So, I did some research that hopefully might help other pilots understand their results and perhaps make some lifestyle changes before small issues become big problems. 

I will try to explain what the numbers mean from a blood test. Please bear in mind that I am not a doctor, and my medical training consists of ripping band-aids off hairy arms and legs (I am not even qualified to put them on in the first place). I am certainly not getting into the argument about whether the range of the numbers is fair or correct and should be changed. These are the rules that the doctors must follow. Regardless your point of view, if you do not get inside the allowable range (with or without medication) then there will be no more flying as a pilot in command for you. Or soup.

Sweet as! 

A few years ago, my blood test results indicated that I could be borderline diabetic, and I needed further testing to make sure that it is not the case. I do not even take sugar in my coffee! 

This spurred me into some research to help understand my results. I wanted to share the little knowledge I have gained with you. 

I will be talking briefly about this pre-diabetic test, because if the number is above 5.5 the doctor must send you for further testing. This involves taking a base blood sample, then you drink the equivalent of 10 cans of cola, wait one hour, they take your blood again, you wait for another hour and they take your blood a third time. Finally, they send you on your merry way to experience the crash that follows the high caused by consuming so much sugar in a short period. 

So, how did I go? I will tell you shortly but first let’s look at the blood test itself.

Analysing the blood test 

Let’s examine the blood tests as requested by CASA and the reasons why they request those tests. I will briefly cover the function of each organ and the tests associated with that organ. It might not be in the same order as you find your blood test result. Different pathology labs may report their results in different formats or use different names or abbreviations. Since the digitalisation of medical results, you may now have to ask for a copy of these from your doctor. 

On each line of results (see page 88), we can see two numbers in parentheses, a lower and upper number. If your results are outside this range, then further tests will be ordered by your doctor to investigate the cause. Your doctor may then prescribe medication, suggest a change of diet or to reduce stress in your life and exercise more. 

The important organs (to CASA) in the human body are as follows.

Liver 

The main function of the liver is to filter the blood coming from the digestive tract, before passing it to the rest of the body. The liver also detoxifies chemicals (like that alcohol stuff that only non-pilots consume) and metabolises drugs and secretes bile that ends up back in the intestines. It also makes proteins important for blood clotting and other functions. 

Liver function tests are groups of blood tests that give information about the state of a patient’s liver. These tests can be used to detect the presence of liver disease and various disorders. 

Kidneys 

The kidneys have four different functions: 

• Filtration 
• Reabsorption 
• Secretion 
• Excretion 

The role of the kidneys is often underrated when we think about our health. In fact, the kidneys play a vital role in the daily workings of the body. They are so important that nature gave us two kidneys to cover the possibility that one might be lost to an injury. Or a Sunday fry-up. 

Humans can live quite well with only one kidney. Some people live a healthy life even though they were born with one missing. However, with no kidney function (or dialysis), death will occur within a few days!

Heart

The heart is a muscular organ that pumps blood through the blood vessels of the circulatory system. Blood tests are taken to help understand a person’s general health and risk factors that may contribute to heart disease. The primary assessment of heart disease begins with history, examination, blood tests and an ECG. Further tests may be requested depending on the results. Sometimes there is a need for a stress test (running on a treadmill while heart functions are monitored). 

Personally, I find it stressful when a defibrillator is ready close by while I am doing the test. Are they going to push me to the point where I have a heart attack? 

Electrocardiogram (ECG) 

This test makes sure that your heart is still beating at the time of the examination (or better still that you have a heart – that might make CASA jealous). But seriously, it actually tests the electrical conduction of the heart. It is compared to previous ECGs and any changes may raise a red flag. 

Urine test 

For the pilot medical this is a screening test for the presence of blood in the urine. Unexplained blood in urine is sometimes treated as cancer until proven otherwise. 

Eyes 

You will have to read two different eye charts, one for long distance and one for short distance. 

If you need glasses to complete the test, then do not forget to take your second pair to the medical exam. CASA requires that you are tested with both your regular and spare pairs of glasses. This is also required during flying operations in case one pair breaks. You will be shown a series of colour charts as well to make sure that you are not colour blind.

‘When someone fails their medical … one of the options is to become friends with a private pilot with a current medical and use them as a safety pilot’ 

The blood test (chemistry panel or metabolic panel) 

For a Class 1 medical you will be sent to have your blood taken. This is done early in the morning on an empty stomach (fasting). Your doctor will then be issued with a page of results, which – as far as we mere mortals are concerned – could be written in Klingon. 

I will explain each test in an order that is not the way it will appear on the blood work. I have grouped the tests by organ or intended screening of disease. 

Gluc (Glucose-blood sugar) – High blood sugar levels may indicate impaired glucose tolerance, prediabetes or diabetes. The fasting blood sugar test is done after at least six hours without food or drink other than water because the levels are affected by food or beverages recently ingested. 

T Prot (Total Protein) – The total protein test is a rough measure of all the proteins in the plasma portion of your blood. Proteins are important building blocks of all cells and tissues. 

A/G ratio (Albumin/Globulin ratio) or Total Protein Test – There are two types of protein your blood — albumin and globulin. The A/G ratio test compares levels of these proteins with one another. Elevated protein levels could indicate a health condition in need of attention such as viral hepatitis or HIV. A low total protein level can suggest a liver disorder, a kidney disorder, or a disorder in which protein is not digested or absorbed properly. 

Alb (Albumin) – This is a protein indicator of liver or kidney problems. 

Glob (Glob Blood Test) – This is used to determine the ratio of albumin to globulin that is in a person’s blood. High total protein levels from the Glob blood test indicate that an individual is suffering from chronic inflammation in some way. This may be an ongoing viral infection, such as hepatitis or HIV. Low protein levels will typically suggest that there is a kidney or liver disorder that is occurring. 

Creatinine – The kidneys process a waste product called creatinine, which comes from muscle tissue. Elevated levels may indicate a problem with kidney function. 

BUN/Creatinine Ratio – This test shows if the kidneys are eliminating waste properly. 

eGFR (estimated Glomerular Filtration Rate) – When the kidneys are damaged, they have trouble removing creatinine from your blood. It is a calculated result based on your creatinine test and other personal factors. 

Lipid Panel (or Lipid Profile) – The lipid panel is a collection of tests measuring different types of cholesterol and triglycerides (fats) in your bloodstream. 

Trig (Triglycerides) – These fats may contribute to heart disease and other health problems. 

Chol (Total cholesterol) – This may be an indicator of your risk of heart disease. 

HDL cholesterol – Also known as “good” cholesterol, HDL (highdensity lipoprotein) protects against heart disease. Low scores are risk factors for heart disease. 

LDL cholesterol – Also known as “bad” cholesterol, LDL (lowdensity lipoprotein) is the substance that clogs arteries and is linked to heart disease. High scores are risk factors for heart disease. 

ALT (Alanine Aminotransferase) – When all is well with your liver, your score on this test should be within range. Anything higher may indicate liver damage. 

AST (Aspartate aminotransferase) – This enzyme is found in heart and liver tissue, so elevations suggest problems may be occurring in one or both of those areas. 

Alk. P (Alkaline phosphatase) – This enzyme is involved in both liver and bone, so elevations may indicate problems with the liver or bone-related disease. 

‘Don’t assume that any issues found during your pilot medical will automatically mean that you are grounded’

Bilirubin – This is another measure of kidney and liver functions. Sometimes the liver can’t process the bilirubin in the body. This can be due to an excess of bilirubin, an obstruction, or inflammation of the liver. When your body has too much bilirubin, your skin and the whites of your eyes will start to yellow. 

Phos (Phosphorus) – Too much phosphorus could indicate a problem with kidneys or the parathyroid gland. 

Potass. (Potassium) – This mineral is essential for relaying nerve impulses, maintaining proper muscle functions, and regulating heartbeats. 

Sodium – Irregularities in sodium levels may indicate dehydration, disorders of the adrenal glands, problems with the liver or kidneys, or excessive intake of salt. 

Bicarb (the bicarbonate or total CO2) – This forms part of an electrolyte panel to identify or monitor an electrolyte imbalance or acid-base (pH) imbalance. An electrolyte panel may be used to help monitor conditions such as kidney disease, lung disorders, and high blood pressure. 

An.Gap (Anion gap) – A measurement of plasma electrical charge which contributes to the acidbase balance. It may indicate uncontrolled diabetes or another metabolic disorder. G

GT (Gamma-glutamyltransferase) – To screen for liver disease or alcohol abuse. Apparently, lots of coffee has been shown to lower this level. (Ed: Note to self, switch to Irish coffees before my next medical.) (Proper doctor: Lots of coffee can also dehydrate you and lead to kidney damage.) (Ed: Grrr. Who designed these stupid bodies?) 

Calcium – Too much calcium in the bloodstream could indicate kidney problems, an over-active thyroid or parathyroid gland, certain types of cancer including lymphoma, problems with the pancreas or a deficiency of vitamin D. 

Corr. Ca (calcium blood) – Reports the level of calcium in the blood, corrected for abnormal albumin levels. If your albumin is OK, then this should be much the same as your calcium reading. 

Chloride – Excess chloride could be a red flag for dehydration, multiple myeloma, kidney disorders or adrenal gland dysfunction. A high-salt diet and/or certain medications are often responsible for elevations in chloride. 

Urea (blood urea nitrogen) – Urea nitrogen is a normal waste product that your body creates after you eat. Your liver breaks down the proteins in your food, and while doing so it creates BUN (blood urea nitrogen). When your kidneys are healthy, they remove the BUN. If your levels are out of the normal range this could mean that either your kidneys or your liver may not be working properly. 

Urate – To detect high levels of uric acid in the blood, which could be a sign of the condition gout. 

LD (Lactate dehydrogenase) – This test measures whether you have tissue damage, kidney disease, or liver disease. 

The last word 

Don’t assume that any issues found during your pilot medical will automatically mean that you are grounded. Many conditions can be corrected completely, or at worst managed so that they do not interfere with your flying. However, as you age, you may have to make some sacrifices with your diet and lifestyle so that you can continue to enjoy the privileges of your pilot licence. 

Rumour has it that CASA uses a formula to calculate your risk of cardiovascular disease. Inputs to this formula include your age, BMI, blood pressure, whether you smoke, your cholesterol and triglyceride levels, diabetic tendencies and ECG results. 

If you want to keep your licence for as long as possible then you can do a few simple things. Don’t smoke, eat a healthy diet (low sugar) and try to stay fit. If in doubt you could ask your GP to regularly monitor your cholesterol and sugar levels and provide advice on lowering those as far as possible. By the way, a balanced diet is not a pie (or croissant) in one hand and a beer (or champagne) in the other, no matter how much we all want that to be true. 

Finally, if all else has failed, you may also have the option to scale back your licence level to a point where your medical status allows you to continue flying at least in some capacity. 

So, how did I go with my elevated glucose levels? The doctor never rang me back therefore I can only assume that must be alright! Soon after, CASA sent me my new medical certificate. Looks like I was not pre-diabetic after all. Rum and Cokes all ’round to celebrate! 

Don’t underestimate the importance of the medical 

It doesn’t take a genius to work out that the whole point of pilot medicals is to look for health problems that may pose a risk to a pilot, their passengers or the public at large. Some issues are blindingly obvious (bad eyesight, poor hearing, epilepsy, the potential to drop dead from heart disease at any moment) and are not compatible with being the pilot in command. But other health problems may not be so obvious to a medical novice like me. 

We often hear so much about conditions like diabetes in the media that we may begin to think that because they seem to be so common, they are not such a big deal. Any tests that indicate the potential for diabetes will raise a red flag with CASA, and for very good reason. Some of the potential problems that diabetics can face (and pilots never want to experience) include: 

• High risk of stroke and heart disease; 
• Risk of loss of consciousness; 
• Problems with eyesight; 
• Fatigue, lack of energy and difficulty concentrating; and 
• Circulation and nerve damage. 

Would you like to be sitting in the back seat of an aircraft with an unmedicated diabetic in charge of your immediate future? Me neither.

Aero Circus was formed by a group of General Aviation pilots with different experience levels from RPL to Grade 1 Instructor. Their aim is to bridge the gap between what the CASA syllabus teaches and what a truly safe or employable pilot needs to know. For more information – including the full version of this article – see their website at aerocircus.com.au.