As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
EVENT SUMMARY STATED THAT RT PACK OVERPRESSURE ON TAKEOFF ROLL. DUE TO LT PACK BEING CONSIDERED INOPERATIVE IAW MEL 21-61-01, THE APU IS REQUIRED TO BE USED ON T/O. IF AVAILABLE IAW FSM PG 5-14-1. USING APU BLEED AIR TO SUPPLY THE REMAINING PACK DURING T/O PREVENTS THE HIGH PRESSURE MSG. AIRCRAFT IS OK TO SERVICE.