In this task, you will be presented with a context passage, a question about that paragraph, and a possible answer to that question. The task is to check the validity of the answer. Answer with "Yes" or "No".

According to the radar reconstruction, American 77 reemerged as a primary target on Indianapolis Center radar scopes at 9:05, east of its last known position. The target remained in Indianapolis Center's airspace for another six minutes, then crossed into the western portion of Washington Center's airspace at 9:10. As Indianapolis Center continued searching for the aircraft, two managers and the controller responsible for American 77 looked to the west and southwest along the flight's projected path, not east-where the aircraft was now heading. Managers did not instruct other controllers at Indianapolis Center to turn on their primary radar coverage to join in the search for American 77. In sum, Indianapolis Center never saw Flight 77 turn around. By the time it reappeared in primary radar coverage, controllers had either stopped looking for the aircraft because they thought it had crashed or were looking toward the west. Although the Command Center learned Flight 77 was missing, neither it nor FAA headquarters issued an all points bulletin to surrounding centers to search for primary radar targets. American 77 traveled undetected for 36 minutes on a course heading due east for Washington, D.C. By 9:25, FAA's Herndon Command Center and FAA headquarters knew two aircraft had crashed into the World Trade Center. They knew American 77 was lost. At least some FAA officials in Boston Center and the New England Region knew that a hijacker on board American 11 had said "we have some planes." Concerns over the safety of other aircraft began to mount. A manager at the Herndon Command Center asked FAA headquarters if they wanted to order a "nationwide ground stop." While this was being discussed by executives at FAA headquarters, the Command Center ordered one at 9:25. The Command Center kept looking for American 77. At 9:21, it advised the Dulles terminal control facility, and Dulles urged its controllers to look for primary targets. At 9:32, they found one. Several of the Dulles controllers "observed a primary radar target tracking eastbound at a high rate of speed" and notified Reagan National Airport. FAA personnel at both Reagan National and Dulles airports notified the Secret Service. <sep>What caused concerns over the safety of other aircraft began to mount?<sep>No contact
No

What a time of it Dawson's Landing was having! All its life it had been asleep, but now it hardly got a chance for a nod, so swiftly did big events and crashing surprises come along in one another's wake: Friday morning, first glimpse of Real Nobility, also grand reception at Aunt Patsy Cooper's, also great robber raid; Friday evening, dramatic kicking of the heir of the chief citizen in presence of four hundred people; Saturday morning, emergence as practicing lawyer of the long-submerged Pudd'nhead Wilson; Saturday night, duel between chief citizen and titled stranger. The people took more pride in the duel than in all the other events put together, perhaps. It was a glory to their town to have such a thing happen there. In their eyes the principals had reached the summit of human honor. Everybody paid homage to their names; their praises were in all mouths. Even the duelists' subordinates came in for a handsome share of the public approbation: wherefore Pudd'nhead Wilson was suddenly become a man of consequence. When asked to run for the mayoralty Saturday night, he was risking defeat, but Sunday morning found him a made man and his success assured. <sep>Why did Dawson's Landing wake up?<sep>Because the duelists' subordinates ran around yelling to wake up everyone
No

The one person who, by his interference, could have settled all doubts was debarred by circumstances from interfering in the matter. Wykham Delandre had quarrelled with his sister--or perhaps it was that she had quarrelled with him--and they were on terms not merely of armed neutrality but of bitter hatred. The quarrel had been antecedent to Margaret going to Brent's Rock. She and Wykham had almost come to blows. There had certainly been threats on one side and on the other; and in the end Wykham, overcome with passion, had ordered his sister to leave his house. She had risen straightway, and, without waiting to pack up even her own personal belongings, had walked out of the house. On the threshold she had paused for a moment to hurl a bitter threat at Wykham that he would rue in shame and despair to the last hour of his life his act of that day. Some weeks had since passed; and it was understood in the neighbourhood that Margaret had gone to London, when she suddenly appeared driving out with Geoffrey Brent, and the entire neighbourhood knew before nightfall that she had taken up her abode at the Rock. It was no subject of surprise that Brent had come back unexpectedly, for such was his usual custom. Even his own servants never knew when to expect him, for there was a private door, of which he alone had the key, by which he sometimes entered without anyone in the house being aware of his coming. This was his usual method of appearing after a long absence. <sep>Did Margaret hurl a bitter threat at Wykham before or after being ordered to leave the house?<sep>Before being ordered to leave the house
No