Malaysia Airlines stopped using flight code MH370 after the plane disappeared with 239 people aboard - why airlines retire flight numbers after aviation tragedies

Malaysia Airlines MH370: When Malaysia Airlines Flight MH370 disappeared in March 2014, the mystery surrounding the aircraft was only beginning. But one thing changed almost immediately: the flight number itself.

Malaysia Airlines announced that it would retire MH370 and the return-flight designation MH371 after the aircraft disappeared while flying from Kuala Lumpur to Beijing with 239 people aboard. The airline said the decision was made as a “mark of respect” for the passengers and crew, according to NPR.

The Kuala Lumpur-Beijing route was subsequently given the number MH318, while the Beijing-Kuala Lumpur return flight became MH319.


The decision reflected a longstanding practice in aviation: flight numbers associated with major tragedies are sometimes retired so that the numbers do not continue to evoke the events they became associated with.

Why Airlines Retire Flight Numbers After Major Disasters

NPR reported that airlines often retire flight numbers after fatal crashes because the numbers can evoke negative emotions among passengers and crew.

The practice is particularly associated with high-profile accidents. But there is no single, transparent rule governing when a flight number is retired.

Salon.com noted that the decision-making process is “completely opaque,” with historical accidents suggesting that airlines make the decision on a case-by-case basis. How familiar a flight number is to the public can also play a role.

That helps explain why a flight number can become more than simply a code used to identify a route.

MH370 Became One of Aviation’s Most Famous Missing Aircraft

The disappearance of MH370 was unlike a conventional aviation disaster in one crucial respect: the main wreckage of the Boeing 777 was never located.

Britannica says the aircraft disappeared on March 8, 2014, during its flight from Kuala Lumpur to Beijing, with 227 passengers and 12 crew members aboard.

The aircraft's disappearance triggered a search stretching from the Indian Ocean west of Australia to Central Asia. Debris was eventually found, beginning in 2015, but the main wreckage was never located.

Britannica describes the perplexing disappearance as having become one of history's most famous missing-aircraft cases.

What Happened to MH370 Remained Unresolved

The aircraft's communications changed during the flight.

According to Britannica, the last ACARS transmission was sent at 1:07 a.m. The last voice communication from the crew came at 1:19 a.m., while the aircraft's transponder was switched off at 1:21 a.m.

Malaysian military and civilian radar subsequently tracked the plane as it turned around, flew southwest over the Malay Peninsula and then northwest over the Strait of Malacca. Radar contact was lost over the Andaman Sea at 2:22 a.m.

An Inmarsat satellite later received hourly signals from the aircraft, with the last signal detected at 8:11 a.m.

The information helped to reduce the possible locations of the aircraft, but it did not pinpoint the exact location of the wreckage.

The Search Moved Across a Huge Area

Initial searches focused on the South China Sea. After investigators determined that the aircraft had turned west, the search shifted toward the Strait of Malacca and the Andaman Sea.

Britannica reported that analysis of Inmarsat signals subsequently indicated two possible arcs where the plane could have been: one extending south into the Indian Ocean southwest of Australia and another stretching north across Asia.

On March 24, Malaysia's prime minister announced that analysis by Inmarsat and the U.K. Air Accidents Investigation Branch had concluded that the flight had crashed in a remote part of the Indian Ocean about 2,500 kilometres southwest of Australia.

The search for wreckage continued, but the aircraft itself remained missing.

Debris Finally Appeared More Than a Year Later

The first confirmed piece of debris was discovered on July 29, 2015, when the aircraft's right-wing flaperon was found on Réunion.

Over the following year and a half, 26 more pieces were found on the shores of Tanzania, Mozambique, South Africa, Madagascar and Mauritius.

Britannica says three of the 27 pieces were positively identified as coming from MH370, while another 17 were thought likely to have come from the aircraft.

Some of the debris came from the cabin interior, indicating that the aircraft had broken up. However, it could not be determined whether that happened in the air or when the plane hit the ocean.

The Final Report Could Not Explain Why MH370 Disappeared

The governments of Malaysia, Australia and China called off their search for MH370 in January 2017. Ocean Infinity later received permission to continue searching, but that effort was also called off.

Malaysia issued its final report in July 2018.

According to Britannica, investigators considered mechanical malfunction extremely unlikely. They concluded that the change in flight path likely resulted from manual inputs, but they could not determine why the aircraft disappeared.

That distinction is important: investigators reached conclusions about some aspects of the flight, but the reason for the disappearance remained unresolved.

Theories About MH370 Ranged From Mechanical Failure to Suicide

The uncertainty surrounding the disappearance produced numerous theories.

Britannica says theories in the weeks after the disappearance ranged from mechanical failure to pilot suicide. The loss of the ACARS and transponder signals also prompted speculation about hijacking.

However, no individual or group claimed responsibility for a hijacking, and Britannica notes that it appeared unlikely that hijackers would have flown the aircraft to the southern Indian Ocean.

Another theory focused on deliberate action by one of the pilots. The signals appeared to have been switched off from inside the aircraft, while nothing obviously suspicious had initially been found in the behavior of the captain, first officer or cabin crew before the flight.

A later report cited by Britannica said the captain, Zaharie Ahmad Shah, had flown a simulated route over the southern Indian Ocean on his home flight simulator less than a month before MH370 disappeared. That revelation contributed to speculation about a premeditated pilot-induced suicide, although it did not resolve the mystery.

Other Famous Flight Numbers Were Also Retired

MH370 was not the first flight number to disappear after a major aviation tragedy.

NPR cited Korean Airlines' decision not to use Flight 007 after the aircraft was shot down by Soviet fighter jets in 1983.

Delta Air Lines also retired Flight 191 after a Lockheed TriStar carrying that designation crashed while approaching Dallas-Fort Worth. More than 130 people were killed.

Asiana Airlines changed the flight numbers associated with Flights 214 and 213 after Flight 214 crashed while approaching San Francisco in 2013. The routes were renumbered 212 and 211.

In that case, Asiana spokesman Suh Ki-Won told the Los Angeles Times that many people remembered the flight number and that the airline did not want customers to associate the route with “that kind of image,” NPR reported.

Even Retired Flight Numbers Can Return by Mistake

NPR also reported that United Airlines accidentally reactivated Flight 93 and Flight 175 in 2011 because of a computer glitch.

Both numbers had been retired after the September 11, 2001, terrorist attacks. Flight 93 was commandeered while traveling to San Francisco and crashed near Shanksville, Pennsylvania, after passengers attempted to regain control. Flight 175, traveling from Boston to Los Angeles, crashed into the south tower of the World Trade Center.

According to NPR's report, the numbers were assigned by a computer for future flight sales. Airline officials noticed the error and removed them from the system.

MH370 Was Renumbered, But the Mystery Remained

Malaysia Airlines changed MH370 to MH318 and MH371 to MH319, removing the original flight numbers from its schedule.

The change reflected a practice that has followed other major aviation tragedies: retiring a number that has become inseparably associated with a disaster.

But in MH370's case, the flight number became linked not simply to a crash, but to an aircraft that disappeared, left behind scattered debris and never had its main wreckage located.

The flight number was changed. The questions surrounding the disappearance were not.