The Fuel Tank Flammability Assessment Method (FTFAM) is a Federal Aviation Administration-developed computer model designed as a comparative analysis tool to determine airplane fuel tank flammability as a requirement of Title 14 Code of Federal Regulations Section 25.981. The model uses Monte Carlo statistical methods to determine the average fuel tank flammability of a fleet of airplanes based upon randomly selecting certain unknown variables over defined distributions for a large number of flights. The FTFAM iterates through each flight, calculating the flammability exposure time of each flight given the data input provided by the user. Calculating this flammability exposure time for a sufficiently large number of flights results in statistically reliable flammability exposure data. These calculations can be performed for fuel tank types utilized in transport airplanes, including body tanks located in the fuselage, wing tanks, and center wing tanks. The program can also be modified by the user to determine fuel tank flammability when a flammability reduction means is employed.

This report serves as a user’s manual for this computer model to assist the user in its operation and to discuss the permissible changes that may be made to this model specific to a particular fleet of aircraft. It is updated through version 11 of the FTFAM. The user should reference Advisory Circular 25.981-2A for additional guidance on when to use this model and for a discussion of interpretation of results.