4/20/23 

AIM 

of anger, depression, and anxiety from such events not only decrease alertness but also may lead to taking risks 

that border on self-destruction. Any pilot who experiences an emotionally upsetting event should not fly until 

satisfactorily recovered from it. 

h.  Personal Checklist. 

Aircraft accident statistics show that pilots should be conducting preflight checklists 

on themselves as well as their aircraft for pilot impairment contributes to many more accidents than failures of 

aircraft systems. A personal checklist, which includes all of the categories of pilot impairment as discussed in 

this section, that can be easily committed to memory is being distributed by the FAA in the form of a wallet-sized 

card. 

i.  PERSONAL CHECKLIST. 

I’m physically and mentally safe to fly; not being impaired by: 

I

llness 

M

edication 

S

tress 

A

lcohol 

F

atigue 

E

motion 

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2.  Effects of Altitude 

a.  Hypoxia. 

1. 

Hypoxia is a state of oxygen deficiency in the body sufficient to impair functions of the brain and other 

organs. Hypoxia from exposure to altitude is due only to the reduced barometric pressures encountered at 

altitude, for the concentration of oxygen in the atmosphere remains about 21 percent from the ground out to 

space. 

2. 

Although a deterioration in night vision occurs at a cabin pressure altitude as low as 5,000 feet, other 

significant effects of altitude hypoxia usually do not occur in the normal healthy pilot below 12,000 feet. From 

12,000 to 15,000 feet of altitude, judgment, memory, alertness, coordination and ability to make calculations are 

impaired, and headache, drowsiness, dizziness and either a sense of well-being (euphoria) or belligerence occur. 

The effects appear following increasingly shorter periods of exposure to increasing altitude. In fact, pilot 

performance can seriously deteriorate within 15 minutes at 15,000 feet. 

3. 

At cabin pressure altitudes above 15,000 feet, the periphery of the visual field grays out to a point where 

only central vision remains (tunnel vision). A blue coloration (cyanosis) of the fingernails and lips develops. The 

ability to take corrective and protective action is lost in 20 to 30 minutes at 18,000 feet and 5 to 12 minutes at 

20,000 feet, followed soon thereafter by unconsciousness. 

4. 

The altitude at which significant effects of hypoxia occur can be lowered by a number of factors. Carbon 

monoxide inhaled in smoking or from exhaust fumes, lowered hemoglobin (anemia), and certain medications 

can reduce the oxygen-carrying capacity of the blood to the degree that the amount of oxygen provided to body 

tissues will already be equivalent to the oxygen provided to the tissues when exposed to a cabin pressure altitude 

of several thousand feet. Small amounts of alcohol and low doses of certain drugs, such as antihistamines, 

tranquilizers, sedatives and analgesics can, through their depressant action, render the brain much more 

susceptible to hypoxia. Extreme heat and cold, fever, and anxiety increase the body’s demand for oxygen, and 

hence its susceptibility to hypoxia. 

Fitness for Flight 

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