- Author
-
Cherry, R.
|
Warren, K.
- Title
- Fuselage Burnthrough Protection for Increased Postcrash Occupant Survivability: Safety Benefit Analysis Based on Past Accidents.
- Coporate
- R.G.W. Cherry and Associates Ltd., Hertfordshire, England
- Sponsor
- Department of Transportation, Washington, DC
Civil Aviation Authority, London, England
- Report
-
DOT/FAA/AR-99/57,
September 1999,
169 p.
- Distribution
- AVAILABLE FROM: Federal Aviation Administration William J. Hughes Technical Center's Fire Safety Section's Full-Text technical reports page (in Adobe Acrobat portable document format [PDF]): http//www.fire.tc.faa.gov/reports/report.stm AVAILABLE FROM National Technical Information Service (NTIS), Technology Administration, U.S. Department of Commerce, Springfield, VA 22161. Telephone: 1-800-553-6847 or 703-605-6000; Fax: 703-605-6900. Website: http://www.ntis.gov
- Keywords
-
fuselages
|
burnthrough (failure)
|
postcrash fires
|
occupants
|
survivability
|
aircraft safety
|
aircraft accidents
|
fuel fires
|
pool fires
|
transport aircraft
|
cost benefit analysis
|
ground fires
- Abstract
- The objective of this analysis was to assess the potential benefits, in terms of reduction of fatalities and injuries in worldwide transport aircraft accidents, resulting from improvements in fuselage bumthrough resistance to ground pool fires. The process employed for assessing benefit is considered to give reasonably accurate and consistent results within the limitations imposed by the available data. The methodology gives a reasonable assessment of the tolerance on the predicted levels. The International Cabin Safety Technical Group's Survivable Accidents Database was used to identify past worldwide transport aircraft accidents and extract detailed data for those accidents where fuselage bumthrough was an issue in the survivability of the occupants. Each of these accidents was analysed in depth to assess the number of lives and injuries that would be saved by a fire-hardened fuselage. Seventeen accidents to Transport Category aircraft were identified during the period from 1966 to 1993 where occupant fire injuries were sustained, and fire penetration of the passenger cabin occurred as a result of ground fires. Each accident was divided into scenarios where it was assessed that there was a similar level of threat to the occupants. A mathematical technique was used to model each accident scenario and a Monte Carlo simulation was used to predict a high, median, and low value for the benefits assessed. A range of bumthrough protection times was used, and results are presented for protection times from 30 seconds up to 8 minutes. Eight minutes was chosen to encompass the highest level of protection thought to be practical. The reduction in the structural strength of the fuselage as a result of a pool fire appears to have a limited effect on occupant survival. If this is confirmed it is likely to result in a greater opportunity to find cost beneficial solutions to hardening aircraft against pool fires. The analysis was carried out for the aircraft standards at the time of the accident and assessed for the aircraft if it were configured to the latest airworthiness requirements. Fire hardening of fuselages will provide benefits in terms of enhanced occupant survival and may be found to be cost beneficial if low-cost solutions can be found. The maximum number of lives saved per year, over the period covered by the data, was assessed to be 12.5 for the aircraft in its actual configuration and 10.5 for the aircraft configured to later airworthiness requirements. The variation of benefit with degree of bumthrough protection is approximately an exponential curve with a horizontal asymptote suggesting limited improvement beyond the four to eight minutes additional protection points. The assessed benefit derived from this study is similar in magnitude to that determined from using a representative set of survivable accidents, giving confidence in the results. Costs have not been assessed to ascertain the cost per life saved for possible methods of enhancing the fire penetration of aircraft. However, the relationship between benefit and additional bumthrough protection, derived from this study, will assist in carrying out such an analysis.