Aircraft Accident Brief Ntsb/aab-02/01 (Pb2002-910401): Egypt Air Flight 990, Boeing 767-366er, Su-Gap - National Transportation Safety Board Page 146
ADVERTISEMENT
1 
2 
3 
4 
5 
6 
7 
8 
9 
10 
11 
12 
13 
14 
15 
16 
17 
18 
19 
20 
21 
22 
23 
24 
25 
26 
27 
28 
29 
30 
31 
32 
33 
34 
35 
36 
37 
38 
39 
40 
41 
42 
43 
44 
45 
46 
47 
48 
49 
50 
51 
52 
53 
54 
55 
56 
57 
58 
59 
60 
61 
62 
63 
64 
65 
66 
67 
68 
69 
70 
71 
72 
73 
74 
75 
76 
77 
78 
79 
80 
81 
82 
83 
84 
85 
86 
87 
88 
89 
90 
91 
92 
93 
94 
95 
96 
97 
98 
99 
100 
101 
102 
103 
104 
105 
106 
107 
108 
109 
110 
111 
112 
113 
114 
115 
116 
117 
118 
119 
120 
121 
122 
123 
124 
125 
126 
127 
128 
129 
130 
131 
132 
133 
134 
135 
136 
137 
138 
139 
140 
141 
142 
143 
144 
145 
146 
147 
148 
149 
150 
151 
152 
153 
154 
155 
156 
157 
158 
159 
160 internal mechanisms of any of the PCA slides that it examined. In fact, the EgyptAir PCA slide
anomaly is probably the first ever found by the NTSB. The absence of this background stands in
stark contrast to the extensive historical context that the NTSB devotes to the review of CVR
transcripts to show the uniqueness of the RFO’s response compared to other flight crews.
In most NTSB reports the metallurgical investigation is reported in a separate section to
provide detailed information about the metallurgical findings of the investigation. In the draft
report, however, the NTSB puts the metallurgical work in the wreckage information section and
provides virtually no detail about any findings. This is a critical oversight, since the
metallurgical work is tied directly to the FAA Airworthiness Directives on the sheared bellcrank
rivets, and is related to the Boeing inspection procedure for the rivets which was proved to be
unsatisfactory.
Additionally, if the FAA and Boeing have not found the cause of the rivet shears, it is
irresponsible for the NTSB to provide anything less than a full accounting of the EgyptAir 990
PCA and bellcrank rivet examinations. In fact, the findings were that two of the three bellcrank
rivets on the right elevator sheared in a direction different from the third bellcrank assembly rivet
on the same side. The draft report fails to identify the right elevator as the location of these
conflicting shear patterns and makes only a very general (and vague) statement that some
assemblies sheared in a direction opposite to the others.
18.
(Page 39) The statement that there were no scrapes or abrasions on the bias
spring is misleading and incomplete. The bias spring is composed of a metal that is harder than
other PCA components and, therefore, would naturally resist any physical evidence of a jam.
Moreover, in the USAir 427 accident investigation, the NTSB concluded that a jam could occur
in a similar PCA without leaving any physical mark.
19.
(Page 40) The statement that the fracture surfaces “were consistent with failures
generated by high-speed impact” is misleading and incomplete. This statement is written not just
to advise that the fracture surfaces are consistent with high-speed impact, but also to suggest that
high-speed impact caused the fractures. There is no evidence that these fractures were, in fact,
29
ADVERTISEMENT
0 votes
Related Articles
Related forms
Related Categories
Parent category: Legal