A BAE100 AFTER TKOF IN CLB ACFT LOST THE ATTITUDE HDG REF SYS AND RETURNED TO THE FIELD. FAILURE CAUSED BY SWITCHING THE PWR. NO REF IN THE QRH WARNING THAT THIS PWR SWITCHING COULD CAUSE FAILURE OF THE ATTITUDE HDG REF SYS.

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DURING CLBOUT; WE EXPERIENCED 2 EFIS PROBS. THE TCASII FAIL LIGHT CAME ON AND THE ALT SELECT FEATURE OF THE FLT DIRECTOR WOULD NOT WORK IN MANUAL OR WITH AUTOPLT. REFERRING TO THE QRH DID NOT HELP SINCE THESE FAILURES WERE NOT IDENTED OR DISCUSSED. SINCE WE WERE DEPARTING A HIGH DENSITY ARPT AREA; BOTH SYS WERE DESIGNED TO EASE PLT WORKLOAD AND ASSIST IN TFC AVOIDANCE. WITHOUT GUIDANCE FROM THE QRH; WE RESORTED TO QUICKLY CHKING CIRCUIT BREAKERS AND SWITCH POS. AS WE WERE DOING THIS WE ALSO ENCOUNTERED SOME TURB (JET WASH). WHILE WIGGLING THE AVIONICS SWITCHES TO ENSURE THEY WERE 'ON' THE ATTITUDE/HDG REF SYS HDG SYS FAILED. NOW WITH OUR BIGGER PROB; WE REFERRED TO THE QRH AND RETURNED TO DEP ARPT. WX CONDITIONS AT ALL TIMES WERE VFR. I BELIEVE THAT MOVING THE SWITCHES IN TURB CAUSED A PWR INTERRUPTION TO THE ATTITUDE/HDG REF SYS. LATER ON THE GND; I FOUND A SENTENCE IN THE FLT STANDARDS HANDBOOK (SYS CHAPTER) THAT MENTIONS THAT RECYCLING THE AVIONICS SWITCH INFLT WILL CAUSE LOSS OF THE ATTITUDE/HDG REF SYS. HOWEVER; RECYCLING ON THE GND WILL NOT RESULT IN LOSING ATTITUDE/HDG REF SYS. I AM CONCERNED THAT THIS FACT IS NOT A 'WARNING' IN THE QRH! THE QRH SHOULD AT LEAST MENTION ALL THE SYS PWRED BY THE AVIONICS MASTER SWITCH AND INCLUDE THE WARNING ABOUT LOSS OF ATTITUDE/HDG REF SYS INFLT.