You need to read the given passage and construct a question about the information present in the passage. The question should be answerable from the passage. Most importantly, only those questions are allowed whose answers cannot be determined from a single sentence. Do not generate questions that require only a single sentence to answer. Instead, try to combine two sentences and create a question from that combination. Do not create open-ended questions, i.e., the answers to them cannot be found precisely from the information provided in the passage.

Example input: Paragraph- Sent 1: A Republican bid to keep the government open past Friday includes no new money for the construction of a border wall along the U.S.-Mexico border, according to several congressional aides familiar with ongoing talks.
Sent 2: GOP leaders submitted the new offer Tuesday afternoon in an effort to appease Democrats, whose votes are needed to avert a shutdown of federal agencies, several House and Senate aides said.
Sent 3: However, Republicans also insisted on increases in border security and defense spending, including money to repair existing fencing and new surveillance technology to patrol the nearly 2,000-mile border.
Sent 4: Democrats have indicated that they would support such appropriations so long as no money goes toward an actual wall.
Example output: Who has to be appeased to keep the government open?
Example explanation: This is a good multi-sentence question because, "appease Democrats" is mentioned in Sent 2, while "keep the government open" is part of Sent 1. As this question requires more than one sentences to answer, it's a good question.
Q: Paragraph- Sent 1: 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.
Sent 2: 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.
Sent 3: 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.
Sent 4: Managers did not instruct other controllers at Indianapolis Center to turn on their primary radar coverage to join in the search for American 77.
Sent 5: In sum, Indianapolis Center never saw Flight 77 turn around.
Sent 6: 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.
Sent 7: 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.
Sent 8: 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.
Sent 9: They knew American 77 was lost.
Sent 10: 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."Sent 11: Concerns over the safety of other aircraft began to mount.
Sent 12: A manager at the Herndon Command Center asked FAA headquarters if they wanted to order a "nationwide ground stop."Sent 13: While this was being discussed by executives at FAA headquarters, the Command Center ordered one at 9:25.
Sent 14: The Command Center kept looking for American 77.
Sent 15: At 9:21, it advised the Dulles terminal control facility, and Dulles urged its controllers to look for primary targets.
Sent 16: At 9:32, they found one.
Sent 17: Several of the Dulles controllers "observed a primary radar target tracking eastbound at a high rate of speed" and notified Reagan National Airport.
Sent 18: FAA personnel at both Reagan National and Dulles airports notified the Secret Service.
A:
What was one of the mistakes besides the air traffic control search that lead to America 77 flying for 36 min. undetected?