The last FBI metallurgical examinations or evaluations conducted of any significance, relating to damaged TWA 800 components, were in approximately October 1996.
As directed by you, on January 1, 1997, I elicited a commitment for the services of a retired research scientist and metallographic laboratory specializing in the aluminum alloys primarily comprising the Boeing 747-100.
Since May 1997, the scientist has been researching the location, morphology, and formation fracture mechanics of small holes with "spike tooth" fractures, the only metallurgically significant indicator present at a high strain rate. However, the holes are relatively small (none of which could reasonably have been responsible for "instantaneous" cessation of the recorders), exhibit no apparent preferred concentration, exhibit no apparent isotrophy, and are in matrices which exhibit no characteristics of impulsive loading or proximity to explosive (ordnance) materials.
The scientist has observed no indication of bomb or missile damage, and brings to ten the number of metallurgists officially examining and pronouncing the absence of bomb or missile damage, four from NTSB, three from Boeing, two from FBI Laboratory, and one scientist consultant.
It is noted that three of the aforementioned metallurgists could be considered to have a strong organizational interest in the finding that something other than mechanical failure initiated the catastrophic sequence of events.
The "spike tooth" failures, known to both the NTSB and FBI from other incidents to be the result if high velocity contacts from damaged aircraft components, have recently been duplicated in empirical tests conducted by the NTSB where metal pieces were brought in contact with the aircraft skin at strain rates already known to be available from the forward velocity of the passenger jet and velocities associated with free fall from 13,800 feet. In view of these observations, therefore, it is unreasonable to expect the "spike tooth" failures will be related to any criminal behavior which could have caused the disaster.