Date: 201412
Local time of day: 1801-2400
Location: ZZZ.Airport, US
Flight conditions: Mixed
Weather elements / visibility: 3
Light: Night
Aircraft: B737 Undifferentiated or Other Model
Operator: Air Carrier
Operating under: Part 121
Flight plan: IFR
Mission: Passenger
Flight phase: Takeoff / Launch
ATC / advisory: Tower ZZZ
Aircraft component: Turbine Engine
Component problem: Malfunctioning
Reporter organization: Air Carrier
Reporter function: Pilot Flying; Captain
Reporter qualification: Flight Crew Air Transport Pilot (ATP)
Second reporter function: Pilot Not Flying; First Officer
Anomaly: Aircraft Equipment Problem Critical; Flight Deck / Cabin / Aircraft Event Smoke / Fire / Fumes / Odor
Detector: Person Flight Crew; Person Other Person; Person Passenger
When detected: In-flight
Result: Flight Crew Rejected Takeoff; Flight Crew Returned To Gate; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: Takeoff roll was normal until about 80-90 kts when we felt a jolt and a slight veer to the left. The aircraft began to suddenly and violently shake and got worse as we accelerated. At this point I did not think the aircraft was capable of flight and decided to reject the takeoff. The procedure was initiated at about 110 kts. V1 was about 130 kts. The aircraft came to a stop and I announced to the passengers to 'remain seated'. The First Officer contacted the tower and noted the reject speed. We asked tower to send fire trucks to look for damage or fire. We both assumed we had blown one or more tires as we reviewed the RTO procedure and notes. There were no abnormal engine indications. Once on single frequency with the fire Marshall we shut down the engines and he inspected the aircraft. He found no damage and requested that we start the engines and taxi to the gate. Since I had no idea why the aircraft shook so violently we decided to have the aircraft towed to the gate with the engines off. There were no injuries. At the gate we heard from the Tower that they saw a fireball and a passenger saw 2 fireballs from under the left wing when the event happened.


Second narrative: The weather was rainy; temperature 8 degrees; dewpoint 7 degrees; and it was fully dark at the time. The captain was the pilot flying and the first officer was the pilot monitoring.At approximately 95 knots; both pilots heard the aircraft make a loud bang; the aircraft shuddered; and the nose of the aircraft took an un-commanded and definite jolt to the left. The captain immediately stated 'REJECT' and applied the brakes smoothly and expeditiously to bring the aircraft to a complete stop.Tower stated that for safety purposes they were deploying the fire trucks to confirm that there was no fire on the aircraft.The fire department inspected the aircraft and told us over the radio that there indeed appeared to be a blown tire. However; a couple of minutes later they called back to inform us that they were mistaken; there appeared to be no discernible damage to the aircraft whatsoever.However; as we were about to depart the aircraft; we learned of several eye witness reports (from both passengers and other aircraft) of flames coming from the left engine as well as approximately six loud bangs. Tower confirmed this report when I called them directly to tell them that there was no visible damage to the engine.


Synopsis: A B737 flight crew rejected their takeoff approaching V1 believing they had blown tires on the left side. After stopping fire crews inspected the exterior and found no visible damage. After returning to the gate passengers; ATC and other flight crews reported fireballs and booms had emanated from the left engine.