What was found
(CAN) DURING TRAINING FLIGHT THE GEAR WAS SELECTED DOWN IN THE EMERGENCY MODE. THE LH GEAR WOULD NOT LOCK DOWN WITH HAND PUMP PRESSURE BUT WOULD LOCK DOWN WITH NORMAL SYSTEM PRESSURE. AIRCRAFT LANDED WITH 3 GREEN. THE UPPER SEAR COVER WAS FOUND BENT UPWARDS INTERFERING WITH THE DOWN LOCK HOOK, LIKELY FROM GRAVEL FOD. COVER REPAIRED GEAR SWUNG NORMAL.