1. Homework 2, Problem 4
United Airlines flight 232 crashed near Sioux City, IA, on July 19th, 1989 due to a hardware failure. Use Google with the key words ”flight 232 Sioux City video” and investigate the archival record of the event to answer the following questions.
a.- Construct a Fault Tree that contains a branch representing the sequence of failures leading all the way to the basic event that was ultimately blamed for the failure of the aircraft. See Fig. 3.19, p. 102, text.
b.- Construct an Event Tree displaying the chronological sequence of events starting from the rupture of the turbine disk event. See Fig. 3.23, p. 110, text.
Internet research: Wikipedia reported the following chain of events as the key sequence of failures:
there was a defect in … the titanium disk ingot.
during maintenance, … [a] crack was present and should have been detected at a prior inspection
uncontained failure of its number 2 engine; the fan disk of its tail-mounted General Electric CF6-6 engine broke in two
The fan disk and its blades were not contained by the ductwork, but instead punched through the ductwork and fan cowling
Pieces of shrapnel which went through the right horizontal stabilizer severed the lines of all three hydraulic systems
it broke up during an emergency landing

2. Part a: Fault Tree Aircraft crashes and breaks up.
Shrapnel severs hydraulic system 1.
Shrapnel severs hydraulic system 2.
Shrapnel severs hydraulic system 3.
Disc/blades not contained.
Disc ruptures.
Manufacturing defect.
Defect not detected in maintenance.

3. Part b: Event Tree Mfg defect Defect detected Disc ruptures
Disc/blades contained.
All 3 hydraulic systems severed
Aircraft crashes and breaks up.
True
False
This was the root cause of the accident.
True
False
True
True
1 in 10^9
True
False
False
False
False
False
False
False