of the tank structure due to overpressure. While the NTSB acknowledged that the test conditions at Bruntingthorpe were not fully comparable to the conditions that existed on TWA 800 at the time of the accident, previous fuel explosions in the CWTs of commercial airliners such as Avianca Flight 203 and Philippine Airlines Flight 143 confirmed that a CWT explosion could break apart the fuel tank and lead to the destruction of an airplane. Ultimately, based on "the accident airplane's breakup sequence; wreckage damage characteristics; scientific tests and research on fuels, fuel tank explosions, and the conditions in the CWT at the time of the accident; and analysis of witness information," the NTSB concluded that "the TWA flight 800 in-flight breakup was initiated by a fuel/air explosion in the CWT." In-flight breakup sequence and crippled flight Recovery locations of the wreckage from the ocean (the red, yellow, and green zones) clearly indicated: (1) the red area pieces (from the forward portion of the wing center section and a ring of fuselage directly in front) were the earliest pieces to separate from the airplane; (2) the forward fuselage section departed simultaneously with or shortly after the red area pieces, landing relatively intact in the yellow zone; (3) the green area pieces (wings and the aft portion of the fuselage) remained intact for a period after the separation of the forward fuselage, and impacted the water in the green zone. Fire damage and soot deposits on the recovered wreckage indicated that some areas of fire existed on the airplane as it continued in crippled flight after the loss of the forward fuselage. After about 34 seconds (based on information from witness documents), the outer portions of both the right and left wings failed. Shortly after, the left wing separated from what remained of the main fuselage, which resulted in further development of the fuel-fed fireballs as the pieces of wreckage fell to the ocean. Only the FAA radar facility in North Truro, Massachusetts, using specialized processing software from the United States Air Force 84th Radar Evaluation Squadron, was capable of estimating the altitude of TWA 800 after it lost power due to the CWT explosion. Because of accuracy limitations, these radar data could not be used to determine whether the aircraft climbed after the nose separated. Instead, the NTSB conducted a series of computer simulations to examine the flightpath of the main portion