As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AFTER AIRCRAFT WAS TOWED TO THE GATE FOR A HEADSTART THE L1 DOOR WAS UNABLED TO BE OPENED. UPON INVESTIGATION THE L1 DOOR GUIDE ARM RADUIS LINK SCREW WAS SHEARED. L1 DOOR RADIUS LINK PIN & SCREW REPLACED IAW B737 MM 52-11-21. P/N-BACS12ER08K6 P/N- 141A6076-2 (TC# 20190412013)