Background to the instruction
The need for this instruction arose after several incidents were reported in which a sudden loss of power occurred during operation of the P2008 JC. Remarkably, the engine continued to run smoothly despite the loss of power, indicating a specific cause. After detailed investigation, it was found that the "soft start function" of the ROTAX engine was unexpectedly activated under certain conditions, especially at high power. This could be the reason for the unexpected drop in engine speed.
The soft start system, also known as "Advanced Start System", "Easy Start Unlock" or "Engine Soft Start Feature", is a function that was developed to facilitate the starting process of the engine. However, in certain situations, particularly when the engine is already running and at high power, this function appears to be activated unintentionally, which can lead to a sudden and unexpected drop in performance.
Risks and potential effects
The consequences of such an unpredictable loss of power are considerable. For the pilot, this means an increased workload and a potential stress factor, especially if the situation occurs during a critical part of the flight, such as during take-off or landing. In the worst case scenario, this could even lead to a loss of control of the aircraft, which poses a serious risk to the safety of the crew and passengers.
Risk minimisation measures
To address this potentially unsafe situation, TECNAM has published a Service Bulletin (SB) that stipulates the deactivation of the soft start function on the engine. The instruction is clear: the system must be deactivated and restarting is only permitted if the manufacturer, TECNAM, has issued the appropriate authorisations. This is to ensure that the aircraft can be operated safely until the issue has been resolved.
The AD is considered a temporary measure until new mitigating findings are available from the engine or aircraft manufacturers. This shows that the safety of flight operations is a top priority and that all parties involved are working closely together to find a permanent solution to this problem.
Further developments and recommendations
It is expected that further investigations will take place in the coming months to determine the exact cause of the problem and develop a long-term solution. Aircraft owners and operators of P2008 JC models are urged to strictly follow TECNAM's instructions and take all necessary measures to ensure the safety of their aircraft.
The publication of this AD shows once again how important it is for manufacturers and operators in the aviation industry to work closely together in order to recognise and eliminate potential safety risks at an early stage. Although the deactivation of the soft-start system is a temporary restriction, it serves the overarching goal of maximising safety in flight operations.
Source references:
DAEC