As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
STRONG ACID ODOR LEVEL AT 3000' ISOLATED TO PACK 1 -PERFORMED TSM 05-50-810-831. ALL SIGNS POINT TO HYDRUALIC LEAK. CHECKED FOR EXTERNAL LEAKS IAW AMM 29-00-00. NO LEAKS NOTED. PERFORMED GVI OF APU INTAKE NO HYDRAULIC FLUID TO NOTE. REF LP 3547342-1 FOR FURTHER WORK CONTINUATION.