377 

Federal Aviation Administration, DOT 

Pt. 60, App. C 

(3) Simulation of Computer Controlled Air-

craft using software emulation of helicopter 
boxes; 

(4) Simulation using software avionics or 

rehosted instruments. 

c. Figure C2C illustrates the total trans-

port delay for a non-computer-controlled 
helicopter or the classic transport delay test. 
Since there are no helicopter-induced delays 
for this case, the total transport delay is 
equivalent to the introduced delay. 

d. Figure C2D illustrates the transport 

delay testing method using the real heli-
copter controller system. 

e. To obtain the induced transport delay 

for the motion, instrument and visual signal, 
the delay induced by the helicopter con-
troller should be subtracted from the total 
transport delay. This difference represents 
the introduced delay and should not exceed 
the standards prescribed in Table C1A. 

f. Introduced transport delay is measured 

from the flight deck control input to the re-
action of the instruments and motion and 
visual systems (See Figure C2C). 

g. The control input may also be intro-

duced after the helicopter controller system 
input and the introduced transport delay 
may be measured directly from the control 
input to the reaction of the instruments, and 
simulator motion and visual systems (See 
Figure C2D). 

h. Figure C2E illustrates the transport 

delay testing method used on a flight simu-
lator that uses a software emulated heli-
copter controller system. 

i. It is not possible to measure the intro-

duced transport delay using the simulated 
helicopter controller system architecture for 
the pitch, roll and yaw axes. Therefore, the 
signal should be measured directly from the 
pilot controller. The flight simulator manu-
facturer should measure the total transport 
delay and subtract the inherent delay of the 
actual helicopter components because the 
real helicopter controller system has an in-
herent delay provided by the helicopter man-
ufacturer. The flight simulator manufac-
turer should ensure that the introduced 
delay does not exceed the standards pre-
scribed in Table C1A. 

j. Special measurements for instrument 

signals for flight simulators using a real hel-
icopter instrument display system instead of 
a simulated or re-hosted display. For flight 
instrument systems, the total transport 

delay should be measured and the inherent 
delay of the actual helicopter components 
subtracted to ensure that the introduced 
delay does not exceed the standards pre-
scribed in Table C1A. 

(1) Figure C2FA illustrates the transport 

delay procedure without helicopter display 
simulation. The introduced delay consists of 
the delay between the control movement and 
the instrument change on the data bus. 

(2) Figure C2FB illustrates the modified 

testing method required to measure intro-
duced delay due to software avionics or re- 
hosted instruments. The total simulated in-
strument transport delay is measured and 
the helicopter delay should be subtracted 
from this total. This difference represents 
the introduced delay and should not exceed 
the standards prescribed in Table C1A. The 
inherent delay of the helicopter between the 
data bus and the displays is indicated in fig-
ure C2FA. The display manufacturer should 
provide this delay time. 

k. Recorded signals. The signals recorded 

to conduct the transport delay calculations 
should be explained on a schematic block 
diagram. The flight simulator manufacturer 
should also provide an explanation of why 
each signal was selected and how they relate 
to the above descriptions. 

l. Interpretation of results. Flight simu-

lator results vary over time from test to test 
due to ‘‘sampling uncertainty.’’ All flight 
simulators run at a specific rate where all 
modules are executed sequentially in the 
host computer. The flight controls input can 
occur at any time in the iteration, but these 
data will not be processed before the start of 
the new iteration. For example, a flight sim-
ulator running at 60 Hz may have a dif-
ference of as much as 16.67 msec between re-
sults. This does not mean that the test has 
failed. Instead, the difference is attributed to 
variation in input processing. In some condi-
tions, the host simulator and the visual sys-
tem do not run at the same iteration rate, so 
the output of the host computer to the visual 
system will not always be synchronized. 

m. The transport delay test should account 

for both daylight and night modes of oper-
ation of the visual system. In both cases, the 
tolerances prescribed in Table C1A should be 
met and the motion response should occur 
before the end of the first video scan con-
taining new information. 

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