Analysis of the Gz environment during air combat maneuvering in the F/A-18 fighter aircraft

The F/A-18 Hornet is a high performance fighter aircraft that equips four squadrons of the Royal Australian Air Force (RAAF). The F/A-18 pilot is regularly subjected to high accelerative forces, particularly during air combat maneuvering (ACM). Anecdotal and experimental evidence suggests that cardiovascular adaptation to repetitive Gz can occur.

The purpose of this study was to document the nature and characteristics of the Gz environment to which the pilot is exposed during air combat maneuvering in the F/A-18 fighter aircraft, in terms of its potential to act as a baroreflex training stimulus. The study also aimed to show that onboard data acquisition systems can provide physiologically useful information.

Two air combat maneuvering sorties were flown. Gz data were downloaded from the F/A-18's onboard computer system for analysis.

ACM engagements in the F/A-18 consist of multiple, frequently repetitive excursions to high +Gz levels. Both sorties involved high peak +Gz levels (+7.21 and +7.09), with many excursions (37 and 61) through a +2 Gz threshold. Approximately 20% of each sortie was spent at or above +2 Gz.

This study confirms the physiologically challenging nature of ACM, involving force environment changes of high intensity and frequency. In addition, it indicates the general nature of the training stimulus applied to the arterial baroreflexes which is responsible for the development of cardiovascular adaptation to +Gz seen in previous studies. It also shows that onboard data acquisition systems can provide physiologically useful information, but are limited by low sampling rates.