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

1000 ft. Table 7 presents these data. Qualitative analysis
revealed that eight conflicts were between the closer spaced 17R
and 17L (i.e., 5280 ft) runways.
I :
I i
4.2.4 Decision Tree Analysis.
A comprehensive review of the eight conflicts that resulted in a
miss distance of less than 500 ft was conducted. This review
analyzed video tapes, controller response times, controller
message lengths, pilot response times, aircraft performance, site
coordinator notes, technical observer logs, and controller
incident reports. This review was performed to ensure that each
TCV, a) was not the result of a simulation anomaly, and b) could
have occurred in the operational environment.
Three of the eight TCV's had TGF aircraft evader's. The review
further indicated that an additional three TCV's were the result
of simulation anomalies. In one case, a flight simulator target
was incorrectly located. In the second case, the blunder was
initiated less than 2 nmi from the runway threshold, which
violated procedures outlined in the test plan. In the third
case, the blunder was initiated after the run was completed.
These six cases were removed from further analysis.
Two TCV's were maintained to be valid. These two TCV's are
described in the following section.
4.2.5 Test Criterion Violations.
The following is a description of the valid TCV's in the DIA
simulation. Both TCV's were the result of 30-degree, no-response
blunders.
4.2.5.1 Trans World Airlines 621 into American 204.
The first TCV occurred between Trans World Airlines 621 (TWA621)
and American 204 (AAL204) in the first run on December 3, 1992
(run number 25). Approximately 17 minutes into the run, TWA621
on 17L blundered to the right towards AAL204, a flight simulator
on 17R. The ATC message to the endangered aircraft (AAL204)
began 7 seconds after blunder initiation.
AAL204 acknowledged and responded in a timely manner. The 14
second response time was within the normal range of aircraft
response times (Hasman F. and Pratt, M., 1991; Hasman, F:, Pratt,
M., and Jones, A., 1991). The lowest horizontal separation was
235 ft, and the lowest vertical separation was 188 ft. The
resultant slant range miss distance was 301 ft. Further data,
including groundspeeds and altitudes at blunder initiation, can
be found in table 8.
27