A MIG21's inert missile rails fell of the wing pylons on takeoff. The Pilot suspected a transient electrical anomaly observed during engine start caused the latches to release.

Narrative

During takeoff roll; inert missile rails came off wing pylons prior to flight. One came to rest on the runway; while the other came to rest in the grass to the east of the runway. This was observed by ground personnel; who responded with an airport vehicle to remove them prior to utilization of the runway resumed. There was no conflict with any other aircraft; nor was any person or property in danger at any time. I only learned of their departure upon arrival at home base. Nothing was said to me over the radio. Suspected cause is a power spike throughout electrical system during start sequence by inexperienced lineman manning GPU #2. There is no cockpit indication that the catches have/had been released. They were verified as being latched correctly during walk around inspection by me prior to engine start. This is accomplished by visually verifying through a view port; and then manually trying to move the rails by hand. Ordinarily; the catches releasing would have resulted in the rails immediately falling off the pylons; however; as they are inert and have been in position for a sufficient length of time; they hung up until apparently there was enough air load to cause them to release during the take off roll. The rails were irreparably damaged; and they will no longer be utilized on any aircraft ever again. Weight and balance will be amended to reflect their no longer being installed. My recommendation to other MiG-21 operators (and to all that fly with wing stores!) will be to re-inspect latches if there is any sort of electrical anomalies observed during; or after an external power start; and to be especially vigilant when using relatively inexperienced line crew/volunteers. This will also become part of my SOP.