As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
AIRCRAFT WAS GROUNDED: FLIGHT AIR RETURNED TO LAX ON ACCOUNT OF LOSS OF ACARS COMMUNICATION. FLIGHT DECLARED EMERGENCY. MAINTENANCE REPLACED HF-1 XCVR IAW AMM 23-11-33, ALSO, REPLACED HF-2 COUPLER IAW AMM 23-11-36. HF-1 BITE AND OPS TEST NORMAL IAW AMM 23-11-00. REPLACED HF-2 COUPLER IAW AMM 23-11-36. HF-2 BITE AND OPS TEST NORMAL IAW AMM 23-11-00. (SEE SDR # AALA201911259019, AALA201911259054).