09 Health And Aviation Hazards

Question 1

3 types of acceleration

Answer 1

1. Linear - S&L flight
   - Otoliths
2. Radial / centripetal - in a spin / uncoordinated turn
   - rotation about an axis external to the pilot
   - Biggest physiological effect on pilots
3. Angular / Transverse - coordinated turn
   - rotation about an axis internal to the pilot

Question 2

Describe the different Planes of G-Force

Answer 2

Gz - When going Up (pointing down)
-Gz - When going Down (pointing up)

Gx - When going forward (pointing back)
-Gx - When going backwards (pointing forwards)

Gy - When going left (pointing right relative to person facing)
-Gy - When going right (pointing left relative to person facing)

Question 3

Describe the different thresholds and their effects of positive Gz

Answer 3

> 1G:

• Blood pooling in the lower limbs
• increase in hydrostatic pressure

2G:

• Body & limbs become difficult to move
• Cramps in the calf muscles

3G:
- Organs and facial features move down

3. 5G:
   - Grey out (tunnel vision due to lack of oxygen to the rods)

4-5G:
- Trouble breathing (diaphragm pushed down)

5G+:
- Lack of blood in the head -> Black out (unconsciousness)

Question 4

How can the effects of positive Gz be reduced?

Answer 4

• Tensing Muscles

- Anything which reduces the hydrostatic pressure

Question 5

Describe the thresholds and their effects of Negative Gz

Answer 5

Much greater physiological effect.

Withstand up to -2G to -3G.

Reduces hydrostatic variation.

Effects:

• Cherry colour
• Eyes go red
• Organs and facial features move up
• Reduces heart rate
• Red Out

Question 6

Describe the following for Short Term vs Long Term G Forces:

• Length of time
• Max and min G
• Tensed and Relaxed
• Vertical or Aft

Answer 6

Long Term >= 1sec
Short Term < 1sec

Long term:

• Relaxed person: +3.5G for 1sec
• Tensed or anti-G suite: +7 to +8G for 1sec

Short term:

• +25G or -3G Vertical
• +45G or -3G Aft

Question 7

Somatogravic Illusion

Answer 7

• Illusion of climbing or descending when your are not
• Caused by fast acceleration (climbing) or deceleration (descending)
• Effects the Otoliths (utricle and saccule)
• Caused by linear acceleration

Question 8

Somatogyral Illusion

Answer 8

• The illusion of continuing to roll over when moving to straight and level
• Caused when banking for an extended period of time and then moving to straight and level
• Effects the 3 vestibular canals
• Angular acceleration
• AKA the ‘Leans’

Question 9

Graveyard spin

Answer 9

• Suffering from Somatogyral illusion when in a spin

- Combination of turning the wrong direction to correct the spin and pulling up cause a tighter spin

Question 10

Coriolis Illusion

Answer 10

• Illusion of violent rolling, pitching or tumbling during a manoeuvre.
• Caused by moving the head (more than 3 degrees per second) during a manoeuvre
• Keep head still

Question 11

Which is more reliable, vestibular system or the visual system?

Answer 11

Visual system

Question 12

Oculargravic illusion

Answer 12

• Illusion that the instrument panel is moving up or down
• Caused by Somatogravic illusion
• Can give the impression of confirming the climb or descent

Question 13

Oculargyral illusion

Answer 13

• Illusion of the instrument panel moving left or right
• Caused by Somatogyral illusion
• Can appear to confirm the illusion of rolling

Question 14

Spacial disorientation

Answer 14

• AKA ‘situationally unaware’
• Caused by a conflict of information between instruments and senses
• Use horizon to counter
• 80% of accidents caused by Spacial Disorientation are fatal

Question 15

Effects of Alcohol on Spacial Disorientation

Answer 15

• Changes the SG of the fluid in the vestibular system

- Worsens effects

Question 16

What is Vertigo and what causes it?

Answer 16

• Sensation of tumbling or falling

- Caused by a miss-match of information being sent to the CNS

Question 17

Pilots Vertigo

Answer 17

• Specific type of Vertigo
• Most common during manoeuvres such as banking
• E.g. Blocked Eustachean tube, move head during a turn can send conflicting information to the CNS

Question 18

Flicker Vertigo

Answer 18

• Specific type of Vertigo
• Caused by fast flashing or flickering lights
• 5 to 20 flashes per sec

Question 19

Motion Sickness

Answer 19

• Caused by a miss-match in the information sent by the vestibular system and the visual system.
• Effects the gastro-intestinal system
• Proprereseptors contribute to motion sickness

Question 20

Proprioception Illusions

Answer 20

• Aka kinaesthetic illusions.
• Occurs when tightly strapped into a seat.
• The proprioceptors give the illusion you are the correct orientation when you could be upside down.

Question 21

Name the types of Barotruama

Answer 21

• Otic
• Sinus
• Aerodontalga
• Gastro-intestinal

Question 22

Otic Barotruama

Answer 22

• Occurs in the ears
• Blocked Eustachian tube so the ear cannot equal pressures
• Always worse on the descent
  
  • Ear drum is pushed inside the ear
• Can lead to ruptured tympanic membrane
• Effects can be countered by
  
  • Valsalva
  • Frenzel
• Land ASAP if encountered

Question 23

Sinus Barotruama

Answer 23

• Occurs in the 4 sinuses in the skull
  
  • Pockets of air
• If suffering then descend to altitude where it is ok

Question 24

Aerodontalga

Answer 24

• Occurs in the teeth

- Ari pockets in the teeth can crack teeth

Question 25

Gastro-intestinal Barotruama

Answer 25

• Air pockets in the small intestine which cannot escape
• Worse the higher in the intestine the air pocket is
• Reduce chance
  
  • Avoid: gum, fizzy drinks, spicy food, eating just before flight
  • Eat small portions and slower

Question 26

Gastritis

Answer 26

• Inflammation of the stomach lining

- Caused by Poor Diet and Age

Question 27

Gastroenteritis

Answer 27

• Vomiting and diarrhoea
• Most common cause of pilot incapacitation
• Caused by poor diet or food poisoning
• Always prevents flying
• Takes 90 mins from eating to effect
• Wait 90 mins between eating and flying
• Avoid water in countries where you would be at risk