As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT RETURNED TO PLATFORM AS A CONSEQUENCE OF DURING ENGINES STARTING, IGNITION SYSTEM FAILED IN BOTH ENGINES. DURING MAINTENANCE REVISION WAS DETECTED THAT 115VAC WAS NOT AVAILABLE AND SWITCH FASTENERS LOOSEN IN TWO LINES. FASTENERS WERE TIGHTENED AND ENGINES STARTING WAS CORRECT. DURING TRANSIT AT MEX, IGNITION BOX WAS REPLACED IAW MM 74-10-01, TESTED CORRECT.