Three weeks after its disappearance, flight MH370 is still an unsolved mystery. The plane and its occupants seemed at first to have vanished into thin air. However, investigations into the matter quickly yielded telling results of where the Boeing 777 carrying 227 passengers and 12 crew members might have gone, and where it might be now.

Flight MH370, a red-eye flight to Beijing, took off from Kuala Lampur Airport in Malaysia at 12:41 AM local time and was scheduled to land at 6:30 AM. The timeline of what happened aboard is uncertain, but what occurred near the beginning of the flight is known from radar and radio contacts.

At 1:10 AM the aircraft reached its cruising altitude of 35,000 feet, and Malaysian air-traffic controllers still had contact with the crew. The captain wished Malaysian controllers a good night as the plane crossed into Vietnamese airspace at 1:19 AM. The crew had to establish contact with Vietnamese air-traffic controllers at that point, but the Vietnamese never heard from Flight MH370.

Two minutes after the last voice transmission was received, the plane’s transponder ceased to function properly. In contrast to commonly-held beliefs about radar technology, civilian radar systems depend on a transponder signal in order establish the position of an object. Without this signal, no air-traffic controller centers in Malaysia or Vietnam possessed the technology to establish the exact location of the aircraft.

Roughly ten minutes after its disappearance from radar, Flight MH370 was contacted by another aircraft. The captain of the other aircraft attempted to convey Vietnamese air-traffic controllers’ request for MH370 to contact them, but the captain only heard “mumbling [and] static.”

At the time of its disappearance from radar, Flight MH370 was at its cruising altitude about 90 miles off the west coast of the Malay Peninsula; it was still on course. Soon after, however, it began a series of erratic maneuvers.

Military radar, in contrast to the radar systems used by civilian air-traffic controllers, does not depend on a transponder signal, which allowed military radar systems to detect faint blips that were almost certainly Flight MH370. Military radar shows that the aircraft may have descended to an altitude of as low as 12,000 feet, nearly one-third of the altitude it was supposed to maintain. Radar also showed that the flight veered sharply to the left at 1:28 AM, and was now headed toward the Strait of Malacca, which is north of where Kuala Lumpur Airport is located.

Investigators from the United States, after several days of investigation, believed that this sharp turn had been programmed into the aircraft’s flight computer, indicating that one of the crew members had intentionally sent the plane off course. But on March 23^rd Malaysian officials vehemently denied that there was any evidence of foul play by the crew.

Radar signals have revealed that Flight MH370 returned to 29,500 feet by 1:37 AM, showing that the massive dip in altitude was exceedingly sudden, but also brief. Some have speculated that this large drop in altitude indicates that trouble may have occurred on the flight deck, causing a temporary lapse in attention from the pilot and crew. The nature of what the exact trouble might have been is, of course, completely up for speculation. The fact that a signal of this roller-coaster type altitude change was not sent by ACARS is yet another anomaly.

ACARS (Aircraft Communications Addressing and Reporting System) came into wide use in the 1980’s and is a system which communicates vital information about the flight status to air-traffic controllers without the flight crew needing to dedicate time to communicate with the ground. The system aboard the aircraft sends signals at important times in the flight, such as take-off, when the plane reaches its cruising altitude, and as the aircraft comes in for landing. The system, however, can also detect large changes in the flight status, and will automatically communicate the information to air-traffic controllers. Information describing the flight phase, at what time it occurred, amount of fuel, origin of flight, and flight path are among the data sent by the onboard part of the ACARS.

Being that ACARS is a fully automated system, investigators can only conclude that it either malfunctioned or was disabled. With the transponder failure, it seems likely ACARS was also disabled, but exactly what happened to the numerous flight computers is still unknown. After 1:37 AM, only one onboard communication system (Classic Aero) still functioned properly, but told air-traffic controllers little more than that the aircraft’s engines were still running.

Military radar was not able to pick up the entirety of the flight path, but caught blips indicating its location. From the silencing of ACARS until 2:15 AM, radar has shown that MH370 crossed over the Malay Peninsula north of Malaysia, then turned sharply northward on a course toward Thailand.

After 2:15, little is known about the exact flight path. Only the Classic Aero system continued to communicate once every hour indicating the engines were still operating. Radar picked up a few faint signals, leading investigators to believe the aircraft came about, putting it on a southward course. The last signal was communicated at 8:11 AM, indicating that, within an hour, the aircraft plunged into the Indian Ocean.

How far MH370 traveled south is the subject of the newest debate over flight information. Boeing engineers now say the aircraft may have been traveling significantly faster than originally thought, meaning that its fuel would have run out faster. Accordingly, investigators have shifted their search nearly 700 miles northeast of the original search area, bringing the search area to nearly 200,00 square miles.

Planes have spotted 11 large, light-colored, rectangular objects floating just below the surface of the ocean, which may be debris from the aircraft. Some of the objects appear to be anywhere from 52 to 78 feet long. Ships have been deployed to recover the objects for further analysis to determine whether they could have come from MH370. A Chinese ship is scheduled to arrive on March 29^th to recover the first object.