As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
RT PACK INOP ON BOTH APU AND ENG BLEEDS. WORKED FINE ON APU AT GATE. FAILED WHEN SWITCHED TO ENG BLEED. AT GATE RT PACK CHECKED NORMAL WITH APU AIR. FOUND TWO INCH CRACK IN RT HEAT EXCHANGER REHEATER. REMOVED AND REPLACED REHEATER PER AMM. LEAK CHECK GOOD, MPN 194274-4.