UPDATE Time Pressures and Take-Off Trim Trouble
The Incident Flight
At about 0530 Local Time, the flight crew arrived at the aircraft ready to perform flight TL414 from Darwin to Groote Eylandt, NT. The ATSB say:
They discovered that the refueller was running late and the aircraft servicing had not been completed. The aircraft load information also arrived about 10 minutes late. In an attempt to depart on time, the first officer completed the trim sheet more quickly than usual and did not conduct their usual double check to confirm that it was completed correctly.
At about 0555, the crew started the take-off roll. As the aircraft rotated, the captain (the pilot flying) noted the aircraft felt out of trim, so adjusted the trim and completed a normal rotation. After the initial climb, the captain asked to review the trim sheet. The captain found that the first officer did not include 584 kg of baggage and freight in the take-off trim setting calculation.
The captain and first officer recalculated the aircraft trim and found the correct trim setting for the take-off should have been 0.8° nose-up. The crew rechecked the trim sheet which showed the aircraft was within all weight and balance limitations.
The flight proceeded to Groote Eylandt without further incident.
The first officer said that:
Due to the late arrival of the loading paperwork and the passengers sitting in the aircraft longer than was usual, they felt pressured to complete the trim sheet quickly and pass it to the customer service officer who was standing behind them.
The captain commented:
- As the first officer was approaching the end of their training, the captain felt comfortable with the first officer’s ability to complete the trim sheet without error.
- The company operating procedure required both flight crew to sight the trim sheet. However, this did not normally occur in operations.
- The pre-flight delays had compounded to give the first officer 10 minutes to complete the pre-flight paperwork instead of the usual 20 minutes. As part of the training, the captain wanted to observe how the first officer managed the pre-flight delays and did not assist unless requested.
- The day prior to the incident, the captain reported raising concerns regarding the pressure being placed on first officers training to become captains to complete the trim sheet in under two minutes. They felt that the focus during training should be on completing the trim sheets correctly before the speed naturally increases. It is better to take extra time to complete the trim sheet correctly and double check. If the time had been taken to double check, the error may have been identified.
- The captain felt company communications to flight crew had a large focus on flights departing on time. This placed pressure on the flight crew to rush their pre-flight preparations.
- The captain found the manual trim sheets used for EMB-120 operations laborious and presented a high risk of error.
The operators says:
The company standard operating procedure ‘Completion of the Trim Sheet’ has changed from both flight crew being required to sight the trim sheet to include a requirement for both flight crew members to cross check the trim sheet and take-off/landing data card for correctness.
In discussion the ATSB comment:
The NASA Aviation Safety Reporting System Hurry-Up Study examined 125 incident records that involved time related problems. The study found that in 63% of incidents the error took place in the pre-flight phase.
That study suggested the following strategies to reduce the frequency of time-related errors:
- Maintain an awareness of the potential for the ‘Hurry-Up Syndrome’ in pre-flight and taxi-out operational phases.
- When pressures to ‘hurry-up’ occur, particularly in the pre-flight operational phase, it is a useful strategy for pilots to take the time to prioritise their tasks.
- If a procedure is interrupted for any reason, returning to the beginning of that task and starting again will significantly reduce the opportunity for error.
- Practicing positive crew resource management technique will eliminate many errors — effective crew coordination in ’rushed’ situations will catch many potential problems.
- Strict adherence to checklist discipline is a key element of pre-flight and taxi-out task execution.
- Defer paperwork and non-essential tasks to low workload operational phases
The ATSB research report Take-off performance calculation and entry errors: A global perspective concluded that despite advanced aircraft systems and robust operating procedures, accidents continue to occur during the take-off phase of flight.
Data errors, such as the wrong figure being used as well as data being entered incorrectly, not being updated, or being excluded, happen for many different reasons. The ATSB web page Data input errors highlights that no one is immune from data input errors.
However, risk can be significantly reduced through effective management and systems.
It is imperative that the aviation industry continues to explore solutions to firstly minimise the opportunities for take-off performance parameter errors from occurring and secondly, maximise the chance that any errors that do occur are detected and/or do not lead to negative consequences.
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