Date: 201212
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: VMC
Light: Night
Aircraft: EMB ERJ 145 ER/LR
Operator: Air Carrier
Operating under: Part 121
Mission: Passenger
Flight phase: Cruise
ATC / advisory: TRACON ZZZ
Aircraft component: Hydraulic System Lines; Connectors; Fittings
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: First Officer; Pilot Not Flying
Reporter qualification: Flight Crew Commercial
Second reporter function: Pilot Flying; Captain
Anomaly: Aircraft Equipment Problem Critical
Detector: Automation Aircraft Other Automation; Person Flight Crew
When detected: In-flight
Result: Flight Crew Diverted; Flight Crew Executed Go Around / Missed Approach; Flight Crew Landed in Emergency Condition; General Declared Emergency
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: In cruise flight; we received E(1) Hyd Low 1 EICAS message. Noted and monitored Hydraulic level. Level decreased as flight continued to destination. EICAS message E(1) Hyd Fail received after requesting vectors for at least 10 miles final. Pressure in HYD system 1 was approaching close to 0 psi. Crew briefing initiated from Captain; starting from receiving the initial advisory EICAS message leading to the requested vectors for an extended final; and what course of action we should perform in the event of hydraulic 1 failure at each stage of the approach. As briefed we lowered the landing gear; the HYD 1 FAIL message disappeared momentarily during landing gear extension; but soon returned within 15-30 seconds after extension and the decision; as we had briefed; to abort the landing attempt and divert to a nearby airport which we had briefed as a suitable alternate was initiated. During the go around; and appropriate call outs; gear retraction was attempted and the EICAS message LG Disagree was received; and the gear remained in the extended position. The crew decided in the event of HYD 1 failure to cancel landing intentions and divert because ZZZ had runway construction; night conditions; non-standard runway markings; and was not grooved. ZZZ1 was a close alternate that provided adequate runway length; was not under construction; and had appropriate facilities; VFR conditions. We flew to ZZZ1 after initiating the go around procedure and radar vectors; flying at 200 KIAS or less and landed after declaring an emergency; and were towed to the gate. Enroute multiple crew briefings were performed to prepare both crew and passengers; and adequate time was allotted for both pilots and crew to complete briefings and prepare for landing. Appropriate QRH performed for HYD Sys 1 Fail; as well as precautionary Emergency gear extend QRH performed. After landing; Maintenance did find a leak in the hydraulic line on the First Officer side main gear. Some overlapping of roles and communications; but ensured everything was covered. Overall I believe crew was briefed as soon as possible and kept updated with all information as it became available. Some duties were overlapped; but overall; we ensured everything was completed. All crew members verbally acknowledged they had completed appropriate briefings and tasks in preparation for landing.


Second narrative: Enroute we received a HYD 1 Lo qty on the EICAS. Asked Approach for a 10 mile final to make sure gear came down. After putting gear down we received HYD SYS 1 Failure and it went away after about 3 seconds. It then came back after about 5 seconds and we executed a go around and diverted. On the way to the alternate we also received a E1 HYD pump fail. We continued with the gear down and locked. We ran the HYD1 SYS fail QRC from top to bottom. We also asked the Flight Attendant to prepare the cabin for a possible evacuation because we did not know the condition of the nose wheel; whether it was canted or not. We decided to divert because the runway was not under construction; and was a wider runway just in case the aircraft had an uncommanded serving on the ground. We declared an Emergency with approach. Flight Attendant called us back and told us cabin was secure for arrival and we did the approach and landed without incident. Upon lading braking was degraded with only the number 2 thrust reverser available. We then got towed to the gate by station ops.


Synopsis: EMB145 flight crew experiences a HYD 1 LOW QTY EICAS during cruise with normal pressure and elects to continue to destination. During approach after gear extension the system fails and the crew diverts to a nearby airport with longer and wider runways. An uneventful landing ensues and the aircraft is towed to the gate.