G-LOC Due to the Push-Pull Effect in a Fatal F-16 Mishap.

Area of Science:

• Aerospace Medicine
• Human Factors Engineering
• Physiological Effects of Flight

Background:

• High positive Gz forces in aerobatic flight are known to cause G-force induced loss of consciousness (G-LOC).
• The impact of preceding negative Gz (-Gz) exposure on subsequent positive Gz (+Gz) tolerance, termed the "push-pull effect," is less understood.
• This case report examines an F-16 mishap attributed to the push-pull effect.

Observation:

• An F-16 pilot experienced rapid transition from -2.06 Gz to +8.56 Gz within 5 seconds during a training flight.
• Minimal control inputs post-transition suggest transient incapacitation, likely G-LOC or almost loss of consciousness (A-LOC).
• The pilot did not eject, and the aircraft crashed, resulting in a fatality.

Findings:

• The Accident Investigation Board concluded the pilot experienced G-LOC due to the push-pull effect.
• This incident is not the first attributed to the push-pull effect, underscoring its significance.
• The rapid Gz transition from negative to positive likely overwhelmed the pilot's tolerance.

Implications:

• Military and general aviation aerobatics training must continue to emphasize the dangers of the push-pull effect.
• A broader definition of G-LOC may be necessary to include almost loss of consciousness (A-LOC) as part of a continuum.
• Enhanced physiological training protocols are crucial to mitigate risks associated with rapid Gz changes.