Date: 201205
Local time of day: 1201-1800
Location: ZOB.ARTCC, OH
Flight conditions: VMC
Weather elements / visibility: Turbulence
Aircraft: EMB ERJ 170/175 ER/LR
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Cruise
Airspace: Class A ZOB
ATC / advisory: Center ZOB
Reporter organization: Air Carrier
Reporter function: Captain; Pilot Not Flying
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Human factors: Communication Breakdown
Anomaly: ATC Issue All Types; Deviation - Altitude Excursion From Assigned Altitude; Deviation / Discrepancy - Procedural Clearance; Inflight Event / Encounter Loss Of Aircraft Control; Inflight Event / Encounter Weather / Turbulence
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Issued New Clearance; Air Traffic Control Issued Advisory / Alert; Flight Crew Took Evasive Action; Flight Crew Regained Aircraft Control; General Maintenance Action
Contributing factors: Human Factors; Procedure; Weather
Primary problem: Weather

Narrative: While level at FL350 during cruise we encountered severe turbulence leading to the inability to maintain airspeed and altitude of the aircraft. While the pilot flying; was trying to maintain control of the aircraft; I called ATC and notified them that we were unable to maintain flight at FL350 and needed FL330; ATC did not respond. While trying to keep the aircraft from over speeding and entering a low airspeed stall from the airspeed fluctuations; immediate action was required. The pilot flying intervened with the automation; reducing thrust and starting a descent. ATC responded with an altitude verification call and I responded with telling him we called and received no response. We reported the turbulence we had and the fluctuations on the airspeed indicator and VSI. He asked if we wanted to declare an emergency and we declined; due to having control of the aircraft at that time and having no injuries in the cabin. He apologized and told me he was on a 'land line' and didn't hear my call; then gave me a phone number to Quality Assurance. I explained that I had to maintain the safety of the aircraft and had to react appropriately to the condition. The remainder of the flight was uneventful. Upon landing I spoke to ATC via the phone number I received. ATC understood and explained to me that they filed the deviation under a weather anomaly. I wrote the aircraft up for encountering severe turbulence in the maintenance log and was informed by the Mechanic that a fuel leak was found on the left; lower wing outside the engine during the inspection. I don't believe the turbulence could have been prevented; however having an 'over seeing' manager to listen to the radio; while the Air Traffic Controller was on the land line; would have kept us from having to make a decision without ATC knowing what was happening.




Synopsis: EMB-175 Captain reports encountering severe turbulence at FL350 with the First Officer flying. With large airspeed excursions occurring a call to ATC for a lower altitude is made with no response and a descent is initiated without clearance. This is noticed by ATC and the crew is informed that the initial call was missed due to being 'on the land line.'