What happened
On 17 August 2013, a Boeing 757-236, registration G-TCBC, was performing a commercial passenger flight when air traffic control instructed the crew to execute a go-around at Newcastle International Airport. The maneuver was performed incorrectly; the pilot manually advanced the thrust levers instead of using the go-around switch and disconnected the autothrottle while the autopilot remained in approach modes. This caused the aircraft to accelerate rapidly, exceeding the speed limits for the configured flaps and slats.
As the aircraft climbed, the crew encountered a series of technical complications. The high speed caused a slat/flap overspeed, triggering a mismatch message. During the subsequent attempt to resolve the issue using the Quick Reference Handbook (QRH), the crew failed to follow the prescribed steps accurately, leading to further flap/slat disagreements. Due to the technical difficulties, the crew decided to divert to Manchester Airport to utilize a longer runway.
During the diversion, the crew's attention was heavily divided between managing the flight controls and communicating with air traffic control. A low fuel caution light illuminated, indicating that fuel levels were dropping, yet the crew did not immediately action the appropriate checklists. The aircraft eventually arrived at Manchester with a significant fuel imbalance and a total fuel level 700 kg below the required final reserve figure. The aircraft landed without injuries to the 235 passengers or 7 crew members.
The investigation
The AAIB investigation established that the sequence of events began with an improperly executed go-around at an altitude well above the decision height. The investigation found that the crew's workload became unmanageable due to the simultaneous management of the flap/slat malfunction, the diversion, and radio communications.
Investigators noted that the co-pilot was heavily distracted by attempting to program the Flight Management Computer (FMC) and managing radio calls, which contributed to the omission of the After Take-Off Checks. Furthermore, the investigation found that the crew's use of radio terminology was non-standard, leading to confusion with air traffic control regarding the nature of their emergency.
Findings
- The primary cause of the incident was the incorrectly executed go-around maneuver, which led to the aircraft exceeding its structural speed limits for the flap configuration.
- The crew failed to adhere to Standard Operating Procedures (SOPs) during the high-workload phase of the flight.
- Ineffective use of the QRH and a failure to complete checklists led to the persistence of the flap/slat disagreement.
- The crew experienced task saturation, which resulted in the oversight of a low fuel caution and a failure to declare a formal MAYDAY using standard phraseology.
- The commander's focus was partially diverted by personal professional concerns, which may have impacted his ability to manage the crew's workload and pacing.