title: Protection to +12 Gz.
abstract: BACKGROUND
  The U.S. Air Force has developed +Gz-protective equipment that will provide most pilots protection to +9 Gz with minimal-to-no straining. This equipment includes a pressure breathing system called COMBAT EDGE (CE), which is currently operational, and the Advanced Technology Anti-G Suit (ATAGS), which is not yet operational. For future high-performance aircraft design it is important to know the upper limit of various protective equipment and techniques.
  
  
  METHODS
  Six subjects were randomly exposed to a 12-cell matrix composed of +Gz and the following combinations of protective equipment at three seat-back angles (13 degrees, 30 degrees and 55 degrees from the vertical): 1) the standard CSU-13B/P anti-G suit (STD); 2) the STD suit with CE; 3) the ATAGS; and 4) the ATAGS with CE. Relaxed, followed by straining +Gz tolerance was determined using 15-s rapid onset runs to a maximum of +12 Gz. A comprehensive battery of baseline and post-exposure medical surveillance studies was performed to evaluate the medical consequences of these high +Gz exposures.
  
  
  RESULTS
  All 6 subjects were able to achieve +12 Gz with various combinations of +Gz-protective equipment, seat-back angle, and various amounts of straining, from none to maximum. When the data were collapsed over all protective equipment there was a significant (p < 0.05) seat effect. Relaxed tolerance to ROR increased with seat-back angle from 13 degrees to 30 degrees to 55 degrees. There was also a significant protective equipment effect when the data were collapsed over all seat-back angles.
  
  
  CONCLUSIONS
  These data confirm that effortless protection to +9 Gz is available using ATAGS/CE with the 13 degree and 30 degree seat-back angle (F-15, F-16 and F-22) and to +10.5 Gz with a 55 degree seat-back angle. Moreover, with ATAGS/CE, and a moderate degree of straining, +12 Gz is definitely achievable at 55 degrees, even with reduced anti-G suit pressure at 55 degrees. With additional straining +12 GC is also achievable at the 13 degree and 30 degree seat-back angles.
authors.affiliation: School of Aerospace Medicine, Brooks AFB, TX, USA.
authors.forename: J W
authors.initials: JW
authors.lastname: Burns
authors.forename: D J
authors.initials: DJ
authors.lastname: Ivan
authors.forename: C H
authors.initials: CH
authors.lastname: Stern
authors.forename: J C
authors.initials: JC
authors.lastname: Patterson
authors.forename: P C
authors.initials: PC
authors.lastname: Johnson
authors.forename: W E
authors.initials: WE
authors.lastname: Drew
authors.forename: J T
authors.initials: JT
authors.lastname: Yates
mesh_terms: D000054:Acceleration; D000328:Adult; D000337:Aerospace Medicine; D000704:Analysis of Variance; D004867:Equipment Design; D005260:Female; D005676:Gravity Suits; D006339:Heart Rate; D006801:Humans; D018471:Hypergravity / Q000009:adverse effects; D008297:Male; D011312:Pressure