As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
**ATB** AIR TURNBACK REF ITEM 1 ALT DISAGREE ON EICAS. REF ITEM 1 ALT DISAGREE ON EICAS NOTED BY MAINTENANCE SDR GENERATED.FOUND LOOSE B NUT AT FO MAIN STATIC PRESSURE AIR DATA MODULE DM14750. TIGHTENED IN MM20-51-01. PERFORM LOW LEVEL LEAK CK OF FO STATIC SYS IN MM 34-11-00-795-072. TET NML. CLR DEFERAL.