Question - Circumstances when systems are 'locked-out'?
Hi,
I was looking for a but oif insight into under what circumstances (generally) systems can be locked-out.
I have some limited experience with TRU's and I understand that with a typical system, the ICU (Isolation Control Unit) can be locked out to prevent hydraulic actuation along with a mechanical lockout on the TRU itself.
What sort of scenarios would require the TRU to be locked out, and where is the line drawn between locking-out and accepting a delay and repairing/replacing the system?
The reason I ask is that I am working on the design of an engine sub-system which is required to be non-despatch critical, but it is difficult to know where to draw the line where there is a level of failure under which the lock-out feature should be abandoned and it should be accepted that a delay whilst the system is repaired is the only option.
Are TRUs the only example of 'lock-out' features on aircraft or is there any other systems (especially non-despatch critical) that I could look at for guidance?
Hopefully you appreciate I can't be very specific on the application at this stage, but if anybody would like more detail, please ask.
Thanks in advance
Simon