Published Report (DOT/FAA/CT-94-36)

sometimes instructed to disregard controller communications,
thereby not correcting the blunder. A blunder with this
condition will be referred to as a ttno-responsett blunder in this
report.
2.1.3.1 Blunder Scripts.
Blunder scripts were developed from the traffic samples to assist
the test director with creating potential TCV's. All blunders
were initiated by TGF aircraft and occurred after vertical
separation had been lost with aircraft on an adjacent approach.
Sixty percent of the blunders were scripted to occur between the
17L and 17R runways, with the remaining 40 percent occurring
between runways 17R and 16.
Eighty percent of the blunders were scripted to be 30-degree
turns off of the localizer, 17 percent were scripted to be 20-
degree turns, and 3 percent of the blunders were scripted to be
10-degree turns. In order to simulate worst case scenarios, 70
percent of the blunders were scripted as no-response blunders.
Only 30 degree, no-response blunders initiated into flight
simulator targets were assessed in the statistical evaluation of
the data. In previous simulations, controllers have been able to
resolve 10 and 20-degree turns, and these blunders only
contributed to about 1 percent of the total risk.
2.1.3.2 Closest Point of Approach (CPA) Prediction Tool.
The CPA Prediction Tool is a software tool used by the test
director in creating potential TCV's. The software presented the
call signs of the blundering and the evading aircraft in a window
on the test director's display. For each aircraft pair, the CPA
Prediction Tool used aircraft velocities, headings, and blunder
degree in the real-time calculation of a predicted CPA. The time
until the CPA would be reached, given an immediate execution of
the blunder, was also calculated. This information was updated
with each radar update, every 4.8 seconds, and was presented with
the aircraft call signs.
The window had the capacity to accommodate four aircraft pairs at
one time. The aircraft pairs which appeared in the window were
determined by the scripted blunder scenarios; however, the test
director had the capability to create blunders that were not
designated on the blunder scripts. The test director also had
the capability to delete aircraft pairs from the window.
2.1.4 Traffic Samples.
The traffic samples were based on actual arrival traffic into
Denver-Stapleton Airport. Each of the samples was composed of a
representative population of propeller-driven, turboprop, and
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