Ray Cherry, Kevin Warren, and Aaron Chan

The objective of this study was to assess the number of serious injuries and fatalities that might have been avoided by the use of 16-g dynamic seats during the period of 1984 to 1998 for survivable accidents involving transport category aircraft operating under 14 CFR Part 121.

Twenty-five impact- related accidents involving aircraft operating to 14 CFR Part 121, or equivalent, were identified during the period from 1984 to 1998 that may have had seat-related fatal or serious injuries. Each of these accidents was analyzed in detail and a mathematical technique was used to model each accident scenario. Monte Carlo simulations were used to assess a high, median, and low value for the total achievable benefits over the period 1984 to 1998 to U.S. registered aircraft operating under 14 CFR Part 121.

Two methodologies were used. The first was based on worldwide accident data for aircraft operating under 14 CFR Part 121 or equivalent. This analysis results in the following prediction of benefit:

• Reduction in Fatalities = 51 with a 95 percentile range from 33 to 68
• Reduction in Serious Injuries = 54 with a 95 percentile range from 28 to 79

The second analysis was carried out on the accident data pertaining to U.S. aircraft operating under 14 CFR Part 121 only. The analysis of this smaller data set has resulted in the following prediction of lives to be saved:

• Reduction in Fatalities = 23 with a 95 percentile range from 12 to 40

• Reduction in Serious Injuries = 18 with a 95 percentile range from -1 to 32

W. Dwyer

This document is the final report covering the results of a 3-year program entitled "Development of a Supplemental Inspection Document for SA226/SA227 Aircraft." The program focused on developing a supplemental inspection document (SID) for all variants of the SA226 and SA227 based on damage tolerance analysis techniques.

The SA226 and SA227 were designed and certified prior to the advent of modern damage tolerance analysis or FAR amendments, which require the aircraft structure to meet damage tolerance requirements. A major portion of this study consisted of collecting the data and performing the analysis necessary to establish an inspection program based on current damage tolerance methodology. Material and component tests, service experience, strain surveys, stress analysis, and fracture mechanics tools were all utilized to establish this program, which provides inspections and modifications necessary to help ensure the continued . structural integrity of the airplane. These items were accomplished and the SID was developed.

Patricia Cahill

In the fall of 1998, the Federal Aviation Administration (FAA) initiated a program of intense testing, i.e., full-scale testing, intermediate testing, bench-scale testing, and electrical ignition testing on thermal acoustical insulation. This work was prompted by several factors related to current fire test requirements, including the crash of the Swissair MD-11 off the coast of Canada, and the failure of an industry fire test standard called the cotton swab test to characterize the flammability characteristics of a certain foam and fiberglass cover material. Electrical testing was an important part of this program due to the number of reported incidents involving flame spread on thermal acoustical insulation blankets caused by electrical failures such as short circuits. The thermal acoustical insulation films tested in this program were polyimide, metallized and nonmetallized polyester poly (ethylene terepthalate) (PET) and metallized poly (vinyl fluoride) (PVF). Each of these materials was used to fabricate test blankets with 0.42 pound per cubic foot (pcf) fiberglass batting. The test blankets were subjected to 115-and 208-volt electrical arcing tests. This same testing was performed on these blankets with a corrosion inhibiting compound (CIC) sprayed on them. The data showed that the metallized PET blankets ignited with significant flame spread at both voltages with and without CIC. The polyimide and metallized PVF blankets did not ignite at either voltage when tested plain or with CIC application. The plain PET blankets ignited at both voltages, with minimal flame spread, and the fire self-extinguished within seconds. When tested with CIC at 115 volts, flaming in the seam area occurred but self-extinguished within seconds. No ignition occurred at 208 volts. 17.

Ray Cherry and Kevin Warren

The International Cabin Safety Research Technical Group’s Survivable Accidents Database was used to identify past worldwide transport aircraft accidents and extract detailed data for those accidents where explosion 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 might be saved if the fuel tanks were protected with nitrogen inerting systems.

The objective of this analysis was to assess the potential benefits, in terms of reducing fatalities and injuries, resulting from three methods of aircraft fuel tank inerting. The methods analyzed were ground nitrogen inerting in centre fuel tank only, ground nitrogen inerting in all fuel tanks, and onboard nitrogen inerting in all fuel tanks.

Thirteen accidents to transport category aircraft were identified during the period from 1966 to 1995 that may have involved a fuel tank explosion. A mathematical technique was used to model each accident scenario and a Monte Carlo simulation was used to assess a high, median, and low value for the total achievable benefits.

J. G. Quintiere

Data were taken to show the flame spread characteristics of thin materials burning on an insulating substrate. Metalized polyethylene terephthalate (0.20 mm) and paper (0.17 mm) were burned on the surface of glass fiber insulation. Flame spread was measured in the upward or downward facing orientation for the material and in the directions of gravity assistance (up) or gravity opposition (down). Measurements were taken at various angles ranging from a vertical to a horizontal orientation.

A theoretical analysis was developed to predict the flame spread as a function of material properties, sample orientation, and flame spread direction. The one-dimensional theory was in reasonable agreement with paper data. Vertical upward spread was found to yield the highest velocity.