The error signal from {TAIL ~ summer} 82 affects {HEAD ~ the constant speed drive} 66 of each channel in an identical manner 
The error signal from { TAIL ~ summer } 82 affects { HEAD ~ the constant speed drive } 66 of each channel in an identical manner
OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH OTH OTH OTH