cial's arrival, see OEM interview 4 (Mar. 18, 2004). For other OEM officials' arrival, see Richard Sheirer interview
(Apr. 7, 2004); OEM interview 6 (Mar. 24, 2004).
79. For the time of impact, see FAA analysis of United Airlines Flight 175 radar returns and Commission analy-
sis of FAA radar data and air traffic control software logic. For the impact zone, see NIST report,"Interim Report
on the Federal Building and Fire Safety Investigation of the World Trade Center," June 18, 2004, appendix H-41.
For portions undamaged, see Civilian interview 10 (Mar. 24, 2004). For stairwell A remaining passable, see Civil-
ian interview 8 (Mar. 23, 2004); Civilian interview 1 (Mar. 2, 2004); Civilian interview 13 (Mar. 25, 2004); Civil-
ian interview 4 (Mar. 16, 2004).
80. For the sky lobby, see Civilian interview 10 (Mar. 24, 2004). For the condition of people on the impact
floors, see Civilian interview 10 (Mar. 24, 2004); Civilian interview 4 (Mar. 16, 2004); Commission analysis of
911/PAPD calls. For events in the sky lobby after impact, see Civilian interview 10 (Mar. 24, 2004).
81. For conditions in the impact zone above the 78th floor, see Civilian interview 4 (Mar. 16, 2004); Civilian
interview 3 (May 4, 2004); Commission analysis of 911/PAPD calls. For conditions on the 81st floor, see Civilian
interview 4 (Mar. 16, 2004); Civilian interview 3 (May 4, 2004).
82. For the four people, see Civilian interview 1 (Mar. 2, 2004); Civilian interview 13 (Mar. 25, 2004); Civil-
ian interview 4 (Mar. 16, 2004); Civilian interview 8 (Mar. 23, 2004). For the first person to descend stairwell A,
see Civilian interview 13 (Mar. 25, 2004).
83. For civilians ascending the stairs, see Civilian interview 8 (Mar. 23, 2004); Civilian interview 16 (Apr. 27,
2004); Civilian interview 1 (Mar. 2, 2004); Commission analysis of letters written to OSHA concerning the Sep-
tember 11 attacks. For the intention of the group ascending the stairwell and the conditions, see Civilian interview
8 (Mar. 23, 2004).
84. On civilians finding locked doors, see, e.g., Civilian interview 16 (Apr. 27, 2004); Commission analysis of
letters written to OSHA concerning the September 11 attacks. On the lock release order, see Port Authority tran-
scripts of recorded Port Authority calls and radio channels, Sept. 11, 2001, vol. II, channel X, pp. 2531; Port Author-
ity response to Commission interrogatory, May 2004.The Security Command Center did not control access areas
in the Observation Deck and other private tenant spaces. It is unknown whether there were any prior or subse-
quent orders or attempts to release the building's locks.
85. For trouble descending, see Brian Clark testimony, May 18, 2004 (videotaped); Richard Fern testimony,
May 18, 2004 (videotaped); Commission analysis of letters written to OSHA concerning the September 11 attacks.
The conditions of stairwell C are unknown. For conditions in stairwells, see, e.g., Civilian Interview 1 (Mar. 2, 2004);
Civilian Interview 13 (Mar. 25, 2004).
86. For some civilians remaining, see Civilian interview 10 (Mar. 24, 2004). For some civilians ascending, see,
e.g., Civilian interview 1 (Mar. 2, 2004); Civilian interview 11 (Mar. 25, 2004).
87. For conditions in the 90s and 100s, see Commission analysis of 911/PAPD calls. For the 105th floor and
the condition of the less affected area, see Civilian interview 16 (Apr. 27, 2004). For the other areas of the 105th,
88th, and 89th floors, see Commission analysis of 911/PAPD calls.
88. For the callers, see Commission analysis of 911/PAPD calls.There are many variables to consider in deter-
mining whether, and to what extent, stairwell A was actually a viable exit. Knowing that the stairway was initially
passable from at least the 91st floor down, we can conclude that it was likely open from top to bottom, on floors
farther removed from the impact. However, in areas near the impact zone some doors leading to the stairwell may
have jammed.We know that access to stairway A was possible from at least the 81st and 84th floors, and from sev-
eral other floors between the 84th and 91st floor. It is likely that access was possible from floors higher up as well.
It is not known, however, whether 911 callers had a clear path to the stairwell entrance from their locations. Dam-
age caused by the impact of the plane, and the resulting smoke and heat, may have prevented some from being able
to reach the entrance to the staircase; but the stated locations of at least some callers indicate that they were near
stairwell A on their floor. Based on conditions described by civilians who descended stairwell A from at or above
the impact zone, we conclude that stairwell A may have become effectively impassable as the morning progressed.
89. Commission analysis of 911/PAPD calls.
90. Brian Clark testimony, May 18, 2004 (videotaped); Civilian interview 1 (Mar. 2, 2004); Commission analy-
sis of 911/PAPD calls.
91. Commission analysis of 911/PAPD calls.
92. Civilian interview 1 (Mar. 2, 2004); Civilian interview 8 (Mar. 23, 2004); Civilian interview 13 (Mar. 25,
2004); Civilian interview 4 (Mar. 16, 2004); Commission analysis of 911/PAPD calls.
93. OEM interview 1 (Feb. 12, 2004); PANYNJ interview 7 (June 2, 2004); Civilian interview 13 (Mar. 25,
2004); Civilian interview 1 (Mar. 2, 2004); Civilian interview 8 (Mar. 23, 2004).
94. Civilian interview 8 (Mar. 23, 2004); Civilian interview 1 (Mar. 2, 2004); Civilian interview 4 (Mar. 16,
2004); Civilian interview 13 (Mar. 25, 2004); NYPD interview 15, ESU (Mar. 11, 2004).
95. Civilian interview 6 (Mar. 22, 2004); Civilian interview 7 (Mar. 22, 2004) (quotation); Civilian interview
9 (Mar. 3, 2004); Civilian interview 14 (Apr. 7, 2004).
96. Commission analysis of 911/PAPD calls. It is not clear whether callers from below the impact were trapped
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NOTES TO CHAPTER 9
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