What happened
On 30 September 2018, an Airbus A319, registration OE-LQE, was preparing for a commercial passenger flight from London Gatwick Airport. During the cockpit preparation, the pilot monitoring used an Electronic Flight Bag (EFB) to transfer passenger and cargo information from a paper loading form into the aircraft loadsheet software. During this process, an error occurred when inputting the passenger gender and age distribution.
While performing a cross-check, the crew identified a discrepancy of approximately two tonnes between the calculated Zero Fuel Weight and the estimated weight from the flight plan. Despite attempting to locate the source of the error, the crew could not identify the mistake and proceeded with the existing loadsheet. Shortly before departure, a last-minute change to the passenger and cargo load required the crew to use the software's 'Reduced' mode. This update further obscured the original data entry error.
At the runway holding point, the crew discussed the weight discrepancy but decided to proceed with a reduced-thrust takeoff, agreeing to use maximum TOGA thrust if any performance issues were perceived. The takeoff was completed without incident. However, during the cruise phase, a subsequent check of the calculations revealed that the passenger weight had been underestimated by 1,962 kg due to the incorrect population of the age and gender fields.
The investigation
The investigation examined the software interface and the manual data entry process. It was established that the layout and labeling of the paper Loading Form Certificate did not align with the EFB application, making the transcription task difficult. Furthermore, the investigation found that when the crew switched to 'Reduced' mode to account for last-minute changes, the software no as longer displayed the passenger profile data, preventing the crew from verifying the initial error.
Findings
- The primary cause of the incident was a data entry error where passenger distribution figures were mistakenly entered into the gender and age fields.
- The mismatch between the paper loading form and the electronic software format contributed to the initial mistake.
- The use of 'Reduced' mode in the EFB application acted as a barrier to error detection by hiding the erroneous data from the crew's view.
- The crew's contingency plan to use TOGA thrust in the event of performance concerns was potentially unreliable, as pilots may not reliably perceive abnormal acceleration during takeoff.