What happened
In an effort to mitigate risks associated with takeoff procedures, the Dutch Safety Board (OVV) has highlighted the ongoing dangers posed by improper thrust settings during departure. The investigation focused on the risks inherent in reduced thrust takeoffs, a practice used by operators to decrease operational costs. While these procedures are common, they introduce significant hazards, particularly when erroneous parameters are entered into flight management systems or electronic flight bags. Such errors can lead to calculated takeoff speeds and thrust levels being lower than what is actually required for a safe departure, potentially resulting in insufficient runway length for the aircraft to safely lift off.
The investigation
The OVV examined the complexities of takeoff performance and the lack of standardized monitoring. The investigation established that while reduced thrust takeoffs are a frequent cost-saving measure, they inherently reduce safety margins. The board found that the process of manually entering takeoff data is susceptible to human error, especially when changes are made to the takeoff configuration at the last minute. Furthermore, the investigation noted that there is currently no unified airline policy regarding the management of reduced thrust procedures, and the industry lacks a clear understanding of the trade-off between the financial benefits of reduced thrust and the increased safety risks involved.
Findings
- The use of reduced thrust takeoffs increases the risk of erroneous data entry into flight systems.
- There is a lack of standardized procedures across airlines regarding the use of reduced thrust settings.
- Current takeoff performance monitoring is insufficient to alert crews to gross input errors or abnormal accelerations.
- The complexity of developing a full Takeoff Performance Monitoring System (TOPMS) has delayed the implementation of technical solutions.
Safety action
To address these vulnerabilities, the Dutch Safety Board has issued several recommendations:
- EASA and the FAA should lead the development of technical specifications and requirements for an independent onboard system capable of detecting input errors and alerting crews to abnormal accelerations or insufficient runway length.
- The Boeing Company is encouraged to research and develop independent onboard systems for both current and future aircraft to detect performance calculation errors.
- IATA should establish a standardized policy for airlines that includes a formal risk analysis comparing cost savings against the safety risks of reduced thrust operations.
- ICAO should incorporate provisions for these independent monitoring systems into international standards.