The horizontal situation indicator (HSI): Pearson contends that the HSI's needle could have alerted the pilots of their course deviation.He postulates that the needle of each pilot's HSI, capable of showing deviation only up to 8 nautical miles (15 km), should have been "pegged" all the way to the side.The pilots, thus, could in theory have known that they were at least 8 nautical miles (15 km) off course.

Once airborne, an incorrect aircraft system position (of at higher latitudes a small amount) would immediately direct all the flight navigational displays to fly the aircraft to what it thinks is the correct track to the first way point.

Once on the wrong track, all would appear normal, HSI's included.

The deviation exceeded the expected accuracy of the INS (2 nautical miles (3.7 km) an hour) by a factor of six.

Difficulties in making required reports: Pilot and copilot could also have been aware of the aircraft's serious deviation because now, much more than 12 nautical miles (22 km) off course, KAL 007 was too far off course for the pilots to make their required Very High Frequency (VHF) radio reports, and had to relay these reports via KAL Flight 015, just minutes behind and on course (KAL 007, increasingly off course, relied on KAL 015 three times to relay its reports to Anchorage Air Traffic Control).

Flight 007 has been the subject of ongoing controversy and has spawned a number of conspiracy theories.

Some commentators also felt that the International Civil Aviation Organization (ICAO) report into the incident failed to address key points adequately, such as the reason for the aircraft's deviation.

All accounts note that the pilots had several sources of information that could have alerted them to their increasing deviation from their planned route.

The H/E scenario additionally suggests the flight's first officer did know they were flying away from the planned course, but the airline's culture discouraged anyone from questioning the captain's conduct of the flight, so he remained silent.

The reasons put forward for the aircraft's deviation range from a lack of situational awareness by the pilots (ICAO), to a planned and intentional deviation (Pearson), to an Inertial Navigation system (INS) programming error by 10 degrees of longitude during the inputting of the ramp starting position by the crew (Hersh pp.

199–213, the "Harold Ewing (H/E) scenario," which ICAO studied in great detail).

The release of flight data recorder evidence by the Russian Federation in 1993, ten years after the event, seriously challenged many of these theories.