Incident Overview
On 1 September 2011, a Boeing B767-300 aircraft departed from Warsaw Chopin Airport (EPWA) on a scheduled passenger flight to Chicago O'Hare International Airport (KORD). On board were 2 pilots, 9 cabin crew members, and 239 passengers. The aircraft was technically airworthy with no Minimum Equipment List (MEL) deferrals.
Details of the Flight
During the takeoff roll, after the crew pressed the N1 button, the autothrottle failed to arm. The crew continued the takeoff manually, setting engine thrust by hand. After liftoff, during the initial climb, the crew discovered that several systems were inoperative: lateral navigation (LNAV), vertical navigation (VNAV), the left autopilot (AP-L), and the right autopilot (AP-R). Additionally, the flight director bars (FD BAR) were absent on the left Attitude Director Indicator (ADI), and the captain's airspeed indicator lacked the command airspeed bug. The initial departure following the Standard Instrument Departure (SID) was flown manually.
At approximately FL190, the crew engaged the right autopilot and VNAV. The captain switched the instrument source select (INST SOURCE SEL) and flight management computer (FMC) to the right side. Continuously monitoring available instruments, the crew climbed to FL320. After verifying ETOPS conditions, they decided to continue to the destination. The Engine Indicating and Crew Alerting System (EICAS) did not present any caution or warning messages. The STATUS page displayed only "R ENG OH LP1" and "L ENG OH LP2". The Autoland Status Annunciator (ASA) indicated "NO AUTOLAND".
During the flight over the Atlantic Ocean, the forward galley and the center passenger cabin screen ceased to operate. Though these failures did not pose a significant threat, they added to the crew's workload. In the final phase of the flight, a standby horizon (STBY HORIZON) fault occurred. The crew attempted to rectify it by a reset, but without success. The landing at Chicago O'Hare was performed without further incidents. The described anomalies did not recur in subsequent flights. The event was classified as an incident.
Cause
The incident was caused by interface errors in the following systems: MCP/FCC-L, MCP/FCC-R, MCP/TMC, and FMC-L/MCP.
Operator Actions
At Chicago O'Hare, maintenance personnel performed a reset of the MCP, FCC-L, and FCC-R, followed by the required tests per AMM 22-00-07. Additionally, they reset the left and right engine fire detector loops and conducted the prescribed tests. The Polish State Commission for Aircraft Accident Investigation (PKBWL) accepted the operator's findings and closed the investigation without issuing any safety recommendations.