title: Crash-resistant fuel system effectiveness in civil helicopter crashes.
abstract: BACKGROUND
  Crash-resistant fuel systems (CRFS) have demonstrated close to 100% effectiveness in survivable crashes of Army helicopters, but the technology has been slow to transfer into the civil helicopter arena. Federal standards for civil helicopter CRFS are less stringent than those for military helicopters. A reduction in standards for CRFS in military helicopters is being considered.
  
  
  OBJECTIVE
  The goal of this study was to determine whether crashes of civil helicopters with CRFS are less likely to result in post-crash fire than crashes of those without.
  
  
  METHODS
  Crashes of civil helicopters during 1982-2004 were analyzed, comparing Bell 206 helicopters manufactured with CRFS with Aerospatial 350 helicopters manufactured during the same period (post-1981), but lacking CRFS. Bell 206 helicopters with CRFS were also compared with earlier models without CRFS.
  
  
  RESULTS
  The highest proportion of crashes with post-crash fires (11.3%) was in AS-350s manufactured after 1981 (non-CRFS), and the lowest (3.7%) was in Bell 206s (with CRFS) [unadjusted risk ratio (RR) = 3.3, 95% confidence interval (CI) = 1.04, 10.50; adjusted for light and weather, RR = 2.81, Cl = 0.82, 9.69]. Earlier models of Bell 206s without CRFS had higher risk of post-crash fire than post-1981 models with CRFS (7.4% vs. 3.7%; adjusted RR = 2.11, Cl = 0.82, 5.45).
  
  
  CONCLUSIONS
  The results of this study suggest a better performance, in terms of post-crash fire prevention, of CRFS-equipped civil helicopters as compared with those without CRFS. It is possible that CRFS in civil helicopters have not achieved the same degree of effectiveness as CRFS in military helicopters. CRFS should be used more widely in civil helicopters. The more stringent CRFS requirements for military helicopters should not be reduced without further research.
authors.affiliation: Medical Services Corp, U.S. Army, Injury Analysis, Carlsbad, CA 92009-3020, USA.
authors.forename: Mark S
authors.initials: MS
authors.lastname: Hayden
authors.forename: Dennis F
authors.initials: DF
authors.lastname: Shanahan
authors.forename: Li-Hui
authors.initials: LH
authors.lastname: Chen
authors.forename: Susan P
authors.initials: SP
authors.lastname: Baker
mesh_terms: D000060:Accidents, Aviation; D000401:Aircraft; D004867:Equipment Design; D005390:Fires / Q000517:prevention & control*; D005648:Fuel Oils; D006801:Humans; D008889:Military Personnel; D012016:Reference Values; D012189:Retrospective Studies
chemical_list: D005648:Fuel Oils