THE PUSH-PULL EFFECT AND G-INDUCED LOSS OF CONSCIOUSNESS ACCIDENTS INTHE US AIR-FORCE

Background: A recent Canadian Forces CF-18 Hornet aircraft accident ha s focused interest on the push-pull effect (PPE). PPE has not previous ly been identified in U.S. Air Force (USAF) G-Induced Loss of Consciou sness (G-LOC) Accidents. The presence of maneuvers known to cause the push-pull effect (PPEMs) that lead to G-LOC accidents suggests that PP E is operationally significant and is a potential cause of G-LOC accid ents. Methods: USAF accident reports where G-LOC was found to be causa l were reviewed for indications of a PPEM immediately prior to the G-L OC. Terminology in the narratives was used to indicate a PPEM in the a ccident sequences. Results: In 3 of 24 mishaps, the presence of a PPEM was highly probable, while another 4 mishaps were found to have a pro bable association with PPEMs. The probable presence of PPEMs represent s a significant percentage (12.5-29%) of USAF G-LOC accidents. Conclus ion: USAF G-LOC accident reports contained descriptions that indicated the presence of PPEMs in accident sequences. This finding suggests th at the PPE is an operationally significant source of risk for accident s in USAF high-performance aircraft.