What The MH370 Black Boxes Might Not Reveal

As the search for Malaysia Airlines 370 continues, the distinct possibility that it will never be found remains in play.

The similarities to the initial phases of the disappearance of Air France 447 in 2009 are striking.

Though search and rescue personnel had some idea where AF447 went down, it took five days before any debris was found, and before that time people feared it would never be found.

As we approach the two-week mark since the disappearance of MH370, still no sign of it has been found, and as with AF447, people fear we will never find the wreckage of MH370.

The difference between the two events is that there is so much scope as to where MH370 might be. AF447 searchers had a relatively confined area to search, a luxury not afforded with respect to MH370.

Even with the initial AF447 debris found after five days, it still took another two years to locate the main wreck site, four kilometres down in the mid-Atlantic Ocean.

The discovery of that wreck site, and the subsequent discovery and recovery of the two black boxes, allowed investigators to determine beyond most doubt, what happened on that stormy night in 2009.

Let’s step into the future for a moment.

Say some floating debris from MH370 is found in the Indian Ocean a few days from now, and say, using the location of that debris as a starting point, eventually the wreck of the plane is located on the ocean floor.

Say the Flight Data Recorder (FDR) and the Cockpit Voice Recorder (CVR) are also located at the wreck site, and retrieved, as happened with AF447, and that the data they contain is able to be read. There have been cases of black boxes being recovered from the very deep Indian Ocean, such as South African 295 in the 1980’s.

But if they do, what then?

The problem with the MH370 incident, is that they will probably actually show very little at all.

If a major problem occurred on that flight – (mechanical, electrical, fire, bomb, hijack) – at the point the flight became missing, about an hour after take off over the South China Sea, the black boxes would have captured something.

It might not be enough to completely solve the mystery, but it would most likely give the investigators at least something to work with.

While the black boxes almost always provide the hard evidence in crash investigations, in the case of MH370, the black boxes themselves may actually be a problem.

In commercial passenger aircraft, black boxes generally record on a 30-minute loop. The last 30 minutes of data is available inside of them, but after that 30 minutes, the data gets overwritten with the next 30 minutes.

Given it now appears likely that MH370 continued on for a number of hours – (up to 7 hours in some reports) – the 30 minutes of data that existed at the moment the initial problem occurred is long gone.

It has been overwritten.

The infamous Qantas 32 incident in 2010 also saw this happen. Even though the plane eventually landed safely, because the plane was in the air for around 2 hours after the initial engine explosion, the 30 minutes of black box data from the time of the initial explosion was long gone.

The crew asked to hear the CVR during the investigation – but the initial data was gone. There is no electronic record of nature of the incident, or the work that crew did to save 469 lives that day.

Even if the MH370 black boxes are found one day, there will be no hard evidence of what happened in the cockpit or with the aircraft’s systems at the moment the incident started.

Maybe if something sinister has happened, that was the plan – to leave as little evidence behind as possible.

If they are found, they will be able to tell us what happened in the 30 minutes up until the true end of the flight.

If the crew were incapacitated, we won’t hear them saying anything – we might only hear engine noise, and audible cockpit warnings on the CVR. We might only see the plane running out of fuel and gliding gracefully into the ocean on the FDR.

But as for exactly what happened an hour out of Kuala Lumpur that night, they won’t be able to tell anyone anything at all.

Let us hope that for the sake of the families involved, that someone does find something, but right now there is a very high chance that even if the plane is found one day, along with the black boxes, we won’t ever find out what really happened.

  • supine

    I concur that there might not be valuable CVR because of the time elapsed from “disappearance” to “crash” but I think your “30 minutes” is a bit out of date. My understanding was QF32 CVR had 2 hours in it’s memory but a combination of the time spent in the air post explosion and then the inability to shut down one engine which continued to provide power to the CVR which kept running, overwriting recordings from earlier in the incident.

    The FDR should have the entire flight on there and, depending what it can reveal, might hold the only clues the investigators get.

    • I do stand corrected – chapter 30 of Richard De Crespigny’s book does detail that VH-OQA had the ability to record 2 hours on the CVR.

      Quote: “Because the cockpit voice recorder only records the last two hours of a flight finishing when the last engine shuts down. Your Engine 1 didn’t shut down until three hours and 39 minutes after you had landed, so the voice recorder kept recording, overwriting your flight audio with the last two hours of ground audio.”

      The accident aircraft – (9M-MRO) – was manufactured in 2002, and is therefore around five years older than VH-OQA, and likely still had the more traditional “30 minute” recorder.

      Of course, as you say…either length of time is moot, if MH370 carried on for 6 to 7 hours as is believed.