▁the ▁mechanical ▁link ages ▁between ▁the ▁flight ▁controls ▁and ▁the ▁aircraft ▁control ▁surfaces . ▁S ens ors ▁communicate ▁the ▁demanded ▁flight ▁response ▁and ▁then ▁apply ▁real istic ▁force ▁feedback ▁to ▁the ▁fly - by - wire ▁controls ▁using ▁mot ors . ▁The ▁behavior ▁of ▁fly - by - wire ▁flight ▁controls ▁is ▁defined ▁by ▁control ▁algorithms . ▁Ch anges ▁in ▁algorithm ▁parameters ▁can ▁translate ▁into ▁more ▁or ▁less ▁flight ▁response ▁from ▁a ▁given ▁flight ▁control ▁input . ▁Like wise , ▁changes ▁in ▁the ▁algorithm ▁parameters ▁can ▁also ▁translate ▁into ▁more ▁or ▁less ▁force ▁feedback ▁for ▁a ▁given ▁flight ▁control ▁input . ▁The ▁“ correct ” ▁parameter ▁values ▁are ▁a ▁subject ive ▁measure . ▁Therefore , ▁it ▁is ▁important ▁to ▁get ▁input ▁from ▁numerous ▁man - in - the - loop ▁tests ▁to ▁obtain ▁optimal ▁parameter ▁values . ▁ ▁In ▁the ▁case ▁of ▁fly - by - wire ▁flight ▁controls ▁development , ▁H IL ▁simulation ▁is ▁used ▁to ▁simulate ▁human ▁factors . ▁The ▁flight ▁sim ulator ▁includes ▁plant ▁simulations ▁of ▁aer od ynam ics , ▁engine ▁thrust , ▁environmental ▁conditions , ▁flight ▁control ▁dynamics ▁and ▁more . ▁Pro totype ▁fly - by - wire ▁flight ▁controls ▁are ▁connected ▁to ▁the ▁sim ulator ▁and ▁test ▁pil ots ▁evaluate ▁flight ▁performance ▁given ▁various ▁algorithm ▁parameters . ▁ ▁The ▁alternative ▁to ▁H IL ▁simulation ▁for ▁human ▁factors ▁and ▁us ability ▁development ▁is ▁to ▁place ▁prototype ▁flight ▁controls ▁in ▁early ▁aircraft ▁pro tot ypes ▁and ▁test ▁for ▁us ability ▁during ▁flight ▁test . ▁This ▁approach ▁fails ▁when ▁meas