Date: 201506
Local time of day: 1201-1800
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Daylight
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Descent
Airspace: Class C ZZZ
ATC / advisory: TRACON ZZZ
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Anomaly: Aircraft Equipment Problem Critical
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Inflight Shutdown; Flight Crew Landed in Emergency Condition
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: During the enroute descent the Captain (CA) Pilot Monitoring (PM) discovered the E1 oil pressure was indicating at the bottom of the green range; in the mid-40s psi. A slight increase in Thrust Lever (TL) changed the oil pressure to amber. The CA PM checked the oil quantity; aircraft had previous write-ups regarding high oil consumption. E1 indicated 2 quarts.  The CA PM notified the First Officer (FO) Pilot Flying (PF) to continue flying the aircraft normally and performed the low oil pressure QRH checklist; and as a pre-caution reviewed the Engine Failure/Precautionary Engine Shutdown with a view towards suitable runways. The CA PM notified the Flight Attendant (FA) of the abnormal situation; and told the FA to expect a normal landing.  Initially the oil pressure remained in the amber range; however it eventually dropped into the red range; indicating continued loss of oil quantity.  Unable to keep the oil press out of the red; the QRH directs a Precautionary Engine Shutdown. At this time the engine was still producing thrust.  The CA PM notified the FA of the pending engine shutdown; and to still expect a normal landing for cabin purposes.  ATC wanted the flight crew to switch to tower; the CA directed approach to coordinate all clearances for the flight crew. The CA PM and the FO PF rapidly performed the Precautionary Engine Shutdown.  At this point the aircraft was just outside the FAF; the CA PM elected to keep the FO as the PF to prevent introducing [errors] due to changing aircraft control this close to landing.  The aircraft landed normally.  After clearing the runway; the CA requested an outside inspection of the aircraft from the Airport rescue and Fire Fighting (ARFF) commander; who declared the aircraft safe to taxi to the terminal.  After parking at the gate the CA notified company; and consulted whether an NTSB situation existed.  It did not.  A post flight inspection by the contract mechanic revealed oil was leaking through the Generator 3 air intake at the bottom of the cowling.Maintenance procedures.  Aircraft had several maintenance actions performed regarding engine oil loss; and Generator number 3.  Do they need review for adequacy?Training manuals and scenarios don't address when a change in aircraft control would be unwise; given situation and distance to landing.  The CA PM considered taking over PF duties; but insufficient time remained to properly brief the FO on the remaining PM duties; just outside the FAF only 2 minutes of flying time remained.




Synopsis: An EMB-145 Captain reported a precautionary shutdown of the number one engine when low pressure and quantity became an issue.