As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) DURING TAXI TO TAKEOFF, THE FLIGHT CREW NOTICED A STRONG ACID ODOUR IN THE COCKPIT. THE AIRCRAFT RETURNED TO THE GATE WHERE MAINTENANCE DISCOVERED A LEAKING HYDRAULIC LINE IN THE NLG WHEEL WELL. THE LEAKING HYDRAULIC TUBE WAS THE "CLOSE" PRESSURE LINE TO THE NLG DOORS. THE LINE WAS REPLACED AND ALL FURTHER CHECKS WERE COMPLETED PRIOR TO RELEASING THE AIRCRAFT TO SERVICE.