Date: 202106
Local time of day: 0001-0600
Location: ZZZ.TRACON, US
Flight conditions: VMC
Weather elements / visibility: Wind
Light: Night
Aircraft: B757-200
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Cargo / Freight / Delivery
Flight phase: Descent
Airspace: Class B ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: Hydraulic Main System
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Multiengine; Flight Crew Air Transport Pilot (ATP)
Human factors: Training / Qualification; Time Pressure; Communication Breakdown
Second reporter function: Pilot Flying; First Officer
Anomaly: Aircraft Equipment Problem Less Severe; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Landed in Emergency Condition; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: On descent; we received a L hydraulic system pressure message The First Officer continued to fly and i worked through the QRH.  After running the QRH we decided to [advise] with ZZZ Approach. We also had a jumpseater in the back who had just transitioned from the B757 to the [aircraft] so I asked if he would join us in the cockpit as an extra set of eyes. At this time the left hydraulic fluid was so low that alternate means had to be used to extend LE and TE flaps and the landing gear. After an extended down wind to configure we advised the Tower that we would need [to be] towed off of the runway and would be making a full stop on Runway XXL. Captain's landing was smooth and light braking was used and the airplane was brought to a stop at [taxiway] 1X and shut down. After arriving at the gate; the First Officer; jumpseater and I went inside to go over it as I was curious to see what things i could have done better. I had full intention of immediately calling the [Chief Pilot] right after this; but in the mix; I forgot and didn't speak to him for almost an hour and a half. I also did not put that [we advised ATC] in the write up. Being my first [priority event] with the maintenance software I selected the '[advised ATC]' switch to yes and made the wrong assumption that this would suffice. Lesson learned.


Second narrative: On descent into ZZZ; a Left Hydraulic System Pressure malfunction illuminated.  I was Flying Pilot and continued to fly while the Captain commenced QRH procedures for the associated malfunction.  Once the QRH procedures were completed; we [advised] ZZZ Approach.  We elected to get our one jumpseater who is typed in the B757 and [aircraft] to assist as needed in the cockpit. With loss of left hydraulic fluid; we needed to lower flaps/slats and landing gear via alternate means. Both procedures were properly completed as per the QRH. We notified ATC that we would need assistance upon landing and that we would be a full stop on the runway. Landing was uneventful and shutdown was per QRH and normal procedures while on Runway XXL.  Normal communications were established with ZZZ rescue. Company maintenance personnel arrived to the aircraft and towed the jet to Gate XX without incident.  Fire/Rescue escorted jet to gate; no services required.  Suspected hydraulic system pressure/fluid loss on left hydraulic system.


Synopsis: B757 flight crew reported loss of a hydraulic system resulted in a precautionary landing and a tow off the runway to the gate.