Recently my autopilot on my 737ngx fails to engage. I don't have failures selected and in the past have used auto pilot without a problem. Many times actually, so I know its not something new I am doing. I am able to select vnav and lnav but when I push CmdA the button flashes the light but does not go on. I also notice that the screens on the co-pilot side do not seem to be picking up the irs initialization. I have tried to realign the irs to no avail. Again, I have done this a few hundred times in the past without a problem, but my last few flights have had the issue and I am without autopilot. 

I seem to remember that it is possible to break the autopilot even with failures turned off. The intro manual mentions a shear pin in the system that breaks if a heavy handed engagement is carried out. Check in failures & maintenance and see if this applies in your case?

 

Ray

I seem to remember that it is possible to break the autopilot even with failures turned off. The intro manual mentions a shear pin in the system that breaks if a heavy handed engagement is carried out. Check in failures & maintenance and see if this applies in your case?

 

Ray

Yes, its not that. I had that issue long ago.

I'm not sure what is going on. It seems to happen at TNCM mainly. I noticed this time when ground power is connected only the pilot side lights up. The other side comes online once I fire up the apu. However the IRS on the copilot side is all messed up at that time. I was able to realign it finally to get it setup so I could use autopilot, but I have no idea why all of a sudden I am having all this difficulty. The switches on the overhead are all set to run both fmcs/irs etc.