Starter Cutout (correct N2 value) ...

[eudoniga]

Hello folks !

First, is it a correct statement that, on a B737-700, the starter cut-out should happen at 56 % N2 ?

Second, and if so, can anyone of you point me to the line of code where this is programmed within the PMSystems, in order to rectify it ?

Thanks and always three greens !

Eu

[dcutugno]

Yes, for the NG series it is 56% n2, classics series are 52%, don't know why in Pmsystems it is programmed wrongly also they use N1 value >10 for cut engine starters, normally i delete those lines 'cause i have SIOC that handle the code, but you can modify the value to >20 for example that contains,
For Engine 1:

else
manengstart1 = (fs1n1 > 10)
endif

And the for the engine2:

else
manengstart2 = (fs2n1 > 10)
endif

For your reference the section in .lgc file is below:


//EngStart-Begin
if ManEngStart1 = 0
if fsstartflag1 = 0
if bleed1ref > 0
fsStarter1 = 1
else
fsStarter1 = 0
endif
else
manengstart1 = (fs1n1 > 10)
endif
else
if elecbus1 and drive1cover
fsstarter1 = 2
else
fsstarter1 = 0
endif
endif
if ManEngStart2 = 0
if fsstartflag2 = 0
if bleed2ref > 0
fsStarter2 = 1
else
fsStarter2 = 0
endif
else
manengstart2 = (fs2n1 > 10)
endif
else
if elecbus2 and drive2cover
fsstarter2 = 2
else
fsstarter2 = 0
endif
endif
//EngStart-End