Here is James' second part of Echo Flight of Fantasy as posted on Unexplained Mysteries. Again a great read and a must for anyone interested in the 1967 Malmstrom cases.
The discussion regarding the cause of the Echo Flight Incident continues in the 341st Strategic Missile Wing and Combat Support Group Command History covering April-June 1967. "During testing at Boeing, a 30 micro sec Pulse (-10 to 0 volt square wave) was placed on the Self Test Command (STC) line at the C-53P Coupler Logic Drawer interface (STC). Seven out of 10 separate applications of a single Pulse, would cause the system to shut down with a Channel 9 & 12 No-Go.
"Subsequent testing at Autonetics has resulted in the following explanation of what probably happens in the Coupler Logic Drawer. The Pulse inserted is long enough to initiate the Coupler Self test sequence within the C-53P. However, it is not of long enough duration to enable control lines to the computer to place the computer in a Coupler test loop Mode. This causes the Coupler to issue a sequence error due to lack of coincidence between G&C and Coupler Modes. This sequence error, together with the action of two other flip flop outputs (M-17 & M-20), is sufficient to initiate the Coupler and G&C No-Go shut down.
"The effort at Boeing NRA was to determine the source and most likely path of noise Pulse to the Logic Coupler. The results of the Electro Magnetic Pulse (EMP) testing at the LF and Wing IV indicated that the Sensitive Information Network (SIN) were susceptible to noise of the type that could have caused the problem.
"The SIN lines go only from the LCC to all of the LF's in the flight, which could explain the flight peculiar aspect of the problem."
Had a UFO been involved with this incident, the many months of experiment and procedure by USAF personnel, Boeing Corporation and Autonetics scientists and technical representatives would have hardly been necessary. The documents at all levels of the chain of command very plainly establish that the cause of the missile failures was an electronic noise pulse that entered the Logic Coupler within the LCC and shut down all of the LFs from that central location. In July 1967, message traffic from SAMSO, Norton AFB, in California to OOAMA, at Hill AFB, Utah updates recipients on efforts by the Malmstrom AFB Echo Flight investigators to determine the "singular cause." These messages state right up front that it could not yet be determined; it adds, however, that several follow-on actions had been identified.
Read the rest of the article here.