Fs-ia10b reciver with thx9(RM-003) transmitter failsafe problem

Hi
I have the Fs-ia10b reciver with thx9(RM-003) transmitter with APM 2.8 flight Controller, I couldnt set radio failsafe, when i switch off the radio no change happens to the siginals (throttle etc) they stay in postion, I checked the APM atmega 32u2 ship firmware and it with the latest ver. Also i tried to change the setting for the fail safe in the transmitter also no change, can some one help?

Iam also facing same problem, Iam using pixhawk flight controller. Anyboby plz help to enable failsafe.

https://ardupilot.org/copter/docs/radio-failsafe.html