Chapter 16 - Hazards of Aviation

Question 1

What are the symptoms of hypoxia?

Answer 1

Apparent personality change/euphoria

Head ache

Tingling in hand and feet

Pallor and cyanosis

Increased rate of breathing

Muscular impairment

Memory impairment

Question 2

What factors determine a person’s susceptibility to hypoxia?

Answer 2

Altitude

Rate of decompression

Being cold (more energy and therefore oxygen needed for shivering)

Time (exposure)

Exercise

Extremes of temperature

Illness/fatigue

Alcohol/drugs

Smoking

Age

Question 3

What happens to a persons oxygen carrying capacity if they smoke 20-30 cigaretts a day?

Answer 3

It reduces by 4-10%

Question 4

What happens to a person’s physiological altitude if the smoke 20-30 cigaretts a day?

Answer 4

it raises by 4000-5000ft.

Question 5

What level can a person who smokes 20-30 cigaretts a day get hypoxic?

Answer 5

6000ft

Question 6

What are some prevention techniques to stop death/severe consequences from hypoxia?

Answer 6

Having a servicable oxygen supply in flights above 10000ft

Ensure passengers are correctly breifed

Fly only if 100% fit and not on medication or drugs

Ensure heaters are checked and enusure that fresh air is also brought into cabin.

Question 7

What are some treatments for hypoxia while flying?

Answer 7

Go on oxygen

Decsend to sufficient oxygen level but no lower than minimum safe altitude.

Question 8

What are the 4 zones of hypoxic hypoxia?

Answer 8

1) Indifferent zone (GL - 10000ft)
- Night vision affected as low as 5000ft
2) Compensatory zone (10000 - 15000ft)
- Automatic responses provide some protection against hypoxia to maintain homeostasis
3) Distrubance zone (15000 - 20000ft)
- Classic Symptoms of hypoxia
4) Critical zone (20000 - 30000ft)
- Homeostatic system can no longer cope

Question 9

What are the 3 thresholds of hypoxia?

Answer 9

1) Reaction threshold (GL - 7000ft)
- dark adaption is adversely affected as low as 5000ft
2) Disturbance threshold (7000 - 12000ft)
- Auto responses provide some protection against hypoxia trying to maintain homeostasis.
3) Critical threshold - (12000 - 22000)
- Incapacitation with loss of conciousness follws with little or no warning.

Question 10

What is the time of useful conciousness? (TUC)

Answer 10

The time available to a pilot to recognise the development of hypoxia and do something about it.

Question 11

What will TUC be affected by?

Answer 11

Individual fitness

Workload

If the person is a smoker

Obesity

Decompression being progressive or explosive.

Question 12

What are the rough TUCs at different altitudes?

Answer 12

20000ft - 30 minutes

30000ft - 1-2 minutes

35000ft - 30 - 90 seconds

40000ft - 15 - 20 seconds

Question 13

How much will TUC be reduced by if somebody smokes?

Answer 13

50%

Question 14

How does time of effective performance relate to TUC?

Answer 14

It will always be lower or the same.

Question 15

What is hyperventillation?

Answer 15

Lung ventillation in excess of the bodys needs.

Question 16

What can cause hyperventillation?

Answer 16

Anxiety

Motion sickness

Shock

Vibrations

Heat

High G-forces

Pressure breaathing (diving)

Question 17

What are the symptoms of hyperventillation?

Answer 17

Dizziness & feeling unreality

Tingling

Visual disturbances

hot or cold sensations

Anxiety (creating a vicious cycle)

Loss of muscular coordination and impaired performance

Increased heart rate

Spasms

Loss of conciousness

Question 18

What affect does hyperventillation have on the blood acidity?

Answer 18

it makes it more alkaline.

Question 19

How do you treat hyperventillation?

Answer 19

Breathing in a paper bag (reintroduce CO2)

Question 20

What should you do if you are unsure whether someone is hypoxic or hyperventillating?

Answer 20

Treat for hypoxia

Question 21

What effect can decompression have on an aircraft?

Answer 21

The cabin altitude can rise by 5000ft

Sudden drop in temperature can cause mosting or fogging of windows

Question 22

What are the procedures if a cabin decompresses?

Answer 22

1) Put on oxygen maskand set to 100%
2) Declare emergency
3) seatbelt sign on
4) Initiate a controlled descent to the higher of 10000 cabin altitude or minimum safe altitude.
5) Once landed obtain medical advice for recompression

Question 23

Who should you first look after following decompression?

Answer 23

Yourself

Question 24

How does decompression sickness come about?

Answer 24

From nitrogen in the blood coming out of solution in the form of bubbles.

Associated with heights of around 18000 - 25000ft

Unlikey below 14000ft

Question 25

What are the symptoms of decompression sickness?

Answer 25

The Bends - deep pain in large joints

Creeps - intense itching in upper body skin

Chokes - shortness of breath, dry cough, chest pain aggrivated by breathing

Staggers - loss of balance, loss of hearing, virtigo

Post decsent collapse

Question 26

How can decompression sickness be avoided?

Answer 26

Going on oxygen before decompression.

Question 27

How do you treat decompression sickness in flight?

Answer 27

Keep passenger warm and rested

Give them 100% oxygen

Land ASAP or descend if ssomeone is suffering

On landing seek medical assistance regardless of apparent recovery

Question 28

How long should you avoid flying for after diving?

Answer 28

12hrs if compressed air diving

24hrs if 30 feet depth had been exceeded.

Assume worst case if not clear.