What was found
FLAPS STUCK LESS THAN 20 DEGRESS. DURING DETENTION PRIOR TO LANDING, DECLARED EMERGENCY, UNEVENTFUL LANDING RUNWAY 28 LEFT AT KBOI. AMM 27-51-19-04, AMM 27-55-12-04, AMM 27-54-00-05, AMM 27-54-13-04, & AMM 27-50-00-03. FOUND COUPLING SHEARED FROM RT FLAP SIMPLEX BEVEL GEARBOX. R & R BEVEL GEARBOX IAW AMM 27-54-13-04. COMPLIED WITH OPS CHECK IAW AMM 27-54-00-05. OPS CHKD GOOD. COMPLIED WITH MANUAL OPS OF FLAPS SYS TO ZERO IAW AMM 27-50-00-03. R & R FPPU & IPPU IAW AMM 27-51-19-04, & AMM 27-55-12-04. OPS CHKD GOOD IAW AMM 27-54-00-05. FLAP SYS OK FOR SERVICE. ACFT OK FOR SERVICE.