G-load trials

Spiral decent

Airbase De Peel

februari 9th 2008

Report

• Preparation.

• Execution.

• Used registration devices.

• Sensor calibration.

• Retrieved data.

• Conclusions.

• Recommendations.

altitude

450

500

550

600

650

700

750

800

850

900

0:00:00 0:00:04 0:00:09 0:00:13 0:00:17 0:00:22 0:00:26 0:00:30

time [sec]

Sink rate

0

2

4

6

8

10

12

14

16

18

20

0:00:00 0:00:04 0:00:09 0:00:13 0:00:17 0:00:22 0:00:26 0:00:30

time [sec]

Air speed

0

5

10

15

20

25

30

0:00:00 0:00:04 0:00:09 0:00:13 0:00:17 0:00:22 0:00:26 0:00:30

time [sec]

G-forces

0

0.5

1

1.5

2

2.5

3

3.5

0:00:00 0:00:04 0:00:09 0:00:13 0:00:17 0:00:22 0:00:26 0:00:30

time [sec]

Physiological dataHeart rate

020406080

100120140160180200

0 0.001 0.002 0.003 0.004 0.005 0.006 0.007 0.008 0.009

Time

HR

[b

eats

/min

]

1

2

3

0:00:00 0:01:26 0:02:53 0:04:19 0:05:46 0:07:12 0:08:38 0:10:05 0:11:31 0:12:58

time [sec]

G

relation G-load / decent rate

DHV 1-2

1-2L1-2L

1-2L

1-2M1-2M

1.0

1.5

2.0

2.5

3.0

3.5

1.0 3.0 5.0 7.0 9.0 11.0 13.0 15.0 17.0 19.0

V/S [m/s]

G

Conclusion

• At relatively mild spiral descents with descent rate around 13 [m/s] a G-load of more than 3.2 G is reached.

• G-load increases with descent rate.

• Risk of G-LOC can’t be denied.

• It may be assumed that recent fatal incidents during the spiral descent are caused by G-LOC.

G-LOC explained

• Means:“G-load induced Loss Of Consciousness”

• G-load forces the blood away from the head, no matter how hard the heart may work.

• Oxygen and nutrition supply is interrupted.

• Eyes and brains cease functioning.

G-tolerance

• Average value for normal healthy human beings: 4.5 G

• GLOC can occur anywhere between2 and 6.5 G.

• A student F16 pilot went out at 2G.

G-tolerance

G-LOC symptoms

• Grey-out (loss of color in vision)

• Tunnel vision (field of vision narrows)

• Blackout (no vision any more)

• Loss of consciousness

• Brain death

Factors which contribute to a decrease in G-tolerance

• Any illness, even a minor cold.• Chronic or acute hypotension.

(low blood pressure).• Most medicaments.• fatigue.• Non-illegal drugs (alcohol, caffeine).• Dehydration (shortage on drink).• Hypoglycemia (shortage on food).• Stress.

Factors which contribute to a decrease in G-tolerance

• The last 5 bullets are typical circumstances during a week of paragliding !!!!!

What to do when you notice one of the symptoms.

• Stop spiraling immediately.

• Keep your breath and tension all your muscles (this will provide you a couple of extra seconds).

• Don’t try straining techniques like a fighter pilot (this requires long and repeated training. Incorrectly performed shall worsen your situation).

Recommendations

• Organize training program for instructors and pilots.

• Instructors should be trained to make sure they can relay this knowledge to their students.

• Pilots have to be informed.

• This knowledge should be included to pass the paraglider license examination.

Questions

?