Corporate, Featured and Exclusive  |  MARCH 13, 2014 9:44AM

MH370: Some questions and answers

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Azharuddin Abdul RahmanThe Department of Civil Aviation (DCA) director-general Azharuddin Abdul Rahman called MH370’s disappearance an “unprecedented aviation mystery”. As the authorities, investigators and experts continue looking for clues to explain what really happened, KiniBiz compiles some basic questions and provides quick answers.

In a separate post KiniBiz keeps track of notable events that have occurred since the plane went missing — click here for the timeline. Stay tuned for continuous updates of the timeline.

What could have happened to MH370?

Thus far there has been no clear indication of what could have happened to the plane and the 239 people onboard. Authorities are not ruling out any possibility at the moment, which includes terrorism and sabotage.

Are there likely to be survivors?

MAS had previously stated that they fear the worst.

When was radio contact with MH370 lost?

Subang air traffic control had last contact with MH370 at 2.40am, March 8, 2014, handing over to the Ho Chi Minh city control.

What does it mean when radio contact was lost? Does it happen often?

Pilots are generally required to communicate their locations and status via radio to air traffic controllers at regular intervals and when they reach certain locations along their flight path. Between each radio contact there is normally no radio communication.

However planes like the Boeing 777-200ER used by MH370 transmit data on engine performance and other technical aspects automatically at regular intervals.

What altitude did MH370 disappear at and where was it at that point?

radar MH370According to MAS on March 8, 2014, MH370’s last known location before disappearing off the radar was at 065515 North (longitude) and 1033443 East (latitude). It was flying at an altitude of 35,000 ft.

However the Royal Malaysian Air Force (RMAF) later revealed that its radar detected an object believed to be the missing plane 200 miles northwest of Penang at about 2.15am, flying at about 29,500 ft above sea level.

“I am not saying that this is MH370, we are saying that we are working with the experts to determine this aircraft’s identity,” said RMAF chief Rodzali Daud.

When did MH370 go off radar screens? Why does this happen?

MH370 went dark on radar screens about one hour after take-off.

There are two types of radar. The military uses primary radar, which detects everything in its range using electromagnetic waves but cannot identify the object.

On the other hand, air traffic controllers use secondary radar which also detects a plane via electromagnetic waves. The difference is that when a plane picks up electromagnetic waves from a secondary radar, the transponder on the plane would send back a signal identifying the plane.

Secondary radars have a range of 300km around the nearest radar station, which means its coverage may be limited over wide bodies of water. Coverage is also affected by geography, altitude and the Earth surface’s curvature.

In MH370’s case, its transponder stopped submitting signals over the Gulf of Thailand despite still being in range of ground-based radar stations. This effectively means it was invisible to secondary radar, although primary radar would still pick its location up.

What is a transponder?

A transponder is simply a device that transmits radio signals in response to electromagnetic waves from civilian radars or secondary radars. In its response the transponder would tell the ground secondary radar its squawk code, position, altitude and call sign.

Additionally transponders are constantly radar-pinged, which helps air traffic controllers figure out the plane’s speed and direction.

What is a squawk code?

A squawk code is a four-digit identification code that helps air traffic controllers identify each plane on their radar. No other plane within a certain distance would have the same squawk code.

When a plane enters airspace where there is a plane using the same squawk code, the plane would be reassigned to a different squawk code. This is normal for long-distance flights.

Do you need a transponder to be able to detect the plane?

In a nutshell, yes and no depending on the type of radar in question.

What do you mean? What are the radar types?

Primary radars normally used by the military do not need transponders to detect the plane but would not be able to pinpoint the identity of each object detected.

If a plane’s transponder is turned off, the plane would be invisible to secondary radar, which is normally used by air traffic controllers.

Why can’t the secondary radar detect the plane if the transponder is not turned on?

Secondary radar relies on signals coming back from transponders to detect the plane.

MH370 plane missingCan the pilots turn off the transponders?

Yes, they can. Common reasons include the scenario where the transponder is faulty or if there is a fire or other safety risk involving the transponder.

In MH370’s case, the on-board transponder apparently stopped functioning 40 minutes after take-off although it is unclear why.

Can transponders be used to indicate problems on the plane?

Yes. Pilots can send different codes based on the situation, for example the code for hijacking is 7500 while communications failure corresponds to the code 7600. The code for emergencies is 7700.

How is military radar different from civilian radar? What can the former see that the latter cannot?

Military radar can see flying objects irrespective of whether there is a transponder on-board or not. However the radar cannot identify each object as they would only be blips on the radar screen.

Civilian radar relies on the transponder to send a response signal in order to see and identify the object.

Did MH370 turn back?

It is not certain yet but the possibility is not ruled out. MAS had previously stated that they are examining the possibility that MH370 turned back towards Subang.

Additionally Vietnamese authorities previously said it had informed MAS on March 8 that MH370 had turned back due west, although Vietnam did not receive immediate response when it attempted to contact the plane.

“We informed Malaysia on the day we lost contact with the flight that we noticed the flight turned back west but Malaysia did not respond,” Vietnam deputy minister of transport Pham Quy Tieu was quoted as saying by AFP on March 12, 2014.

How can the radar detect a turnback?

Even if the transponder is off, military radar (primary radar) can still detect objects within its range, MH370 included. Based on the last known location and time of the flight when last spotted, it is possible for primary radar to correlate the plane to flying objects that were being tracked at the time.

What is the evidence so far that there was indeed a turnback?

So far the indications toward that possibility have come from military radar data. Authorities are currently investigating the possibility of a mid-flight turnback.

Where can the plane be now given the evidence available?

It is unclear where the plane might be now.

Was there an onboard explosion?

Reports quoted unnamed US officials saying that US spy satellites did not detect any signs of a mid-air explosion in the area where MH370 was last spotted.

Have such planes been missing for this long?

Air France Flight 447The last major airplane crash was in 2009, which saw Air France Flight 447 (an Airbus A330) plunge into the Atlantic Ocean. It was carrying 228 passengers and crew ― none survived. However, it took rescuers five days to find the wreck and three years to determine that ice crystals had caused the auto-pilot to disconnect. Bodies of 74 passengers remain unfound.

As for the Boeing 700 line (MH370 used a Boeing 777-200), the line has “enjoyed one of the best safety records of any jetliner ever built”, said Teal Group aviation consultant Richard Aboulafia.

“(Boeing 777) has provided a new standard in both efficiency and safety,” said Aboulafia.

There are no prior disappearances involving Boeing 777 planes before MH370. Two major previous incidents involved crashes where the planes (Asiana Airlines in 2013 and British Airways in 2008) landed short of their runways.

What is the black box?

Popularly called “black box”, the flight data recorder or accident data recorder (ADR) is a device that records any instructions sent to any electronic systems on an aircraft. Additionally the device also records cockpit conversations including communications with air traffic personnel.

Since these devices are relied on to investigate accidents, the “black box” is made to withstand extreme conditions such as high-speed impact and intense heat. However contrary to its popular name the device is normally coated with bright orange paint to increase visibility in a wreckage.

Is it the only thing which will give final answers?

Not necessarily, although the black box would come in handy. If the wreckage can be found, other clues as to what happened since the plane vanished may be found from the remnants of the plane and its wreckage location.

What is likely to indicate where the plane landed/crashed?

The clearest clue would be its last known flight trajectory before it vanished from both military and civilian radar completely. However it is not confirmed at press time whether the flying object detected by military radar 200 miles northwest of Penang, thought to be MH370, is indeed the missing plane.

Is it more likely to be in the sea or on land?

At present search efforts include both sea and land areas as neither possibility has been ruled out.

Additionally news reports said US investigators suspect MH370 flew on for at least four hours after vanishing from radar on March 8, 2014 as Rolls Royce had received bursts of engine information updates.

However a MAS spokesman has disputed this claim, saying that the data link was severed at the same time as MH370 disappeared. It is unclear if Rolls Royce was able to receive the data independently of MAS. Acting transport minister Hishamuddin Hussein had later said this allegation is not true.

What can one do now to locate the plane?

Authorities have widened the search area on Monday, March 10 2014 after the possibility arose that MH370 may have turned back.

Volunteers can join the crowdsourcing initiatives to comb through available satellite imagery for any sign of a possible wreckage.

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