MH370, Day 5: 777 has five radios, two transponders

The Boeing 777 is equipped with five radios and two transponders, making it next to impossible for failures to be due to electrical or other mechanical failures, a Boeing 777 captain and training instructor tells us.

The ACARS system, which communicates with the ground, is run off one of three VHF radios; the radio would have to be turned off (or failed). There are two HF (High Frequency) radios as well.

The two transponders, which identify the airplane to Air Traffic Control, are not operational simultaneously. If one failed, the pilot has to turn the other on as back-up, says George Nolly, a former airline pilot and Boeing 777/787 instructor.

Malaysian Airlines flight MH370, a 777-200ER, produced no electronic signals and no radio contact was heard from the flight as it vanished from ATC tracking. Military primary radar reportedly tracked the airplane to the Strait of Malacca, where it disappeared from radar.

No debris has been found.

Former investigators with the National Transportation Safety Board and other agencies, pilots, observers and unidentified investigators of this incident are now openly talking about hijacking or pilot action, among some other possibilities, as responsible for this mystery.

Nolly believes whatever happened to the airplane originated in the cockpit, with either an intrusion or one or both of the pilots. These people, whoever they are, would have to turn off the radios and transponders to cut off signals to ATC.

He also said that if the reported turn-around were initiated by a pilot for emergency or return-to-origin reasons, it is standard procedure to call out the turn in order to warn other aircraft in the area.

If this was a cockpit intrusion, Nolly, who has flown for Asian airlines but not MAS, tells us that despite 9/11 and all the security emphasis since then, security throughout Asia is lax. It’s already been reported that the co-pilot on MH370 invited two women to the cockpit on a different flight. Nolly related that he flew for one airline at which the pilot cruised the cabin looking for pretty women and invited them to the cockpit to impress them. He also tells us that it’s not unusual for cockpit access to be granted to passengers throughout the region.

  • It gets curiouser and curiouser. CNN yesterday reported that an unidentified Malaysian military official said MH370 had been tracked to the Strait of Malacca. Later, an identified top general said he didn’t say that. What he didn’t say is whether someone else in the military said it–only that he hadn’t. Go figure.

39 Comments on “MH370, Day 5: 777 has five radios, two transponders

    • No, the VHF and HF radio antennas are separate from the SATCOM. This would also not take out the transponder.
      While a slow decompression is possible in any airplane, I don’t think this is what happened here. First the cabin oxygen system deploys at 12,000′ cabin altitude, not the 13,500′ mentioned in your link. But even at 13,500′ cabin altitude, almost no one is suffering from hypoxia. But the flight crew has warning indicators of a cabin altitude above 8,000′, with warning lights and a gauge. The flight crew would go on oxygen if the cabin altitude could not be corrected.

      • Has anybody mentioned proof of loss of radio, too? Decompression-sickness alone (& the loss of SATCOM together with that) can be the HUMAN factor behind inadequate communication ability from then on. Hypoxia is not the only result, but also rapid expansion of volumes that set out due to pressure differences (lungs perforating; skulls exploding, such as with Comair—kindly excuse me the graphics!) as well as nitrogen bubble formation, similar to divers rising too fast from depth. The latter cause brain infarctions and secondary brain swelling that gets worse over minutes to hours. It is known in mountain climbers, so why not in a plane? In addition, this was after midnight, so everybody would have been at their lowest state of preparedness for disaster compared to any other time of the day, in the plane and on the ground. This ignorance accounts for the reports of high levels of EEG anomalies encountered among pilots routinely tested with it.

        • It doesn’t work that way. I have been through altitude chamber training several times during my USAF flying career. A rapid decompression at FL-350 gives you a ‘time of useful consensus’ in just seconds. Death will follow within about 20-30 minutes (or less). A slower decompression is where hypoxia will show up. Discoloration of the finger nails is a sure sign of hypoxia. But, as I have said before the cockpit has lights and indications to tell cabin altitude. Many airplanes have pressurization leaks, and the aircraft’s pressurization system is usually enough to maintain cabin altitude over these small leaks.

      Exactly along my main line of thought. Such an accident may explain most of what have apparently happened judged on decisions for searching areas and many fragments of information. I have hope they will find the wreckage soon enough and we will then have a clearer picture, but I doubt the basics will differ much from this set of scenarios.

  1. The amount of conflicting information from MH and the Government of Malaysia is astonishing and confusing. None seem to be speaking from the “same sheet of music”. At this point the question “Do they really want this airplane found?” may be a valid one.
    *The initial heading, at FL-350 over the Gulf of Thailand was 025 degrees.
    *Shortly before the lost contact event, Flightracker24 says the heading changed to 040 degrees, a turn to the right. This may be for weather avoidance (my speculation).
    *Transponder, VHF, HF, and ACARs traffic seems to have all failed about the same time. We do not know if this was simultaneous or one piece of equipment at a time.
    * At some point the primary radar returns shows a heading of 333 degrees, a left turn from 025 and 040 degrees, unless the airplane attempted an almost 360 degree turn to the right.
    * Malaysian Air Force says they tracked a target on primary radar to the west or southwest, crossing over their isthmus and into the straits . At this point the target should have been classified as unknown or unidentified. We do not know if the airplanes navigation lights, anti-collision lights, or wingtip strobe lights were on, it was still the middle of the night. So why didn’t the MAF investigate this further. Did they check with Malaysian ATC?
    *The target was tracked by military radar until about 0230, more than an hour after the lost contact with MH-370. By this time ATC would have known they had a lost contact.
    *The Straits of Malacca is a busy ship traffic channel, yet no ship reported sighting the airplane, nor, apparently were any asked.
    *Malaysian and Indonesian Navy and Coast Guards patrol the straits constantly for piracy, yet they did not report (at least publicly) any sighting or radar contact.
    * The USS Pinckney (DDG-91), a Flight IIA Arleigh Burke-class DDG is equipped with AEGIS AN/SPY-1D(V) radar, perhaps the best air defense radar on any warship was in the area, before joining the SAR mission, and would have tracked the unknown target. Yet she has not reported (publicly) anything.

    The mystery continues………

    • There is nothing mysterious about a missing aircraft. We just don’t know where it is.

      The 777 is a big aircraft but relative small compared to the rest of the world. According to our current knowledge MH370 did not disintegrate at the position of last received transponder signal otherwise debris would have been found already.

      According to Malaysian Air Force an aircraft was spotted west bound. Radars of USS Pinckney may have been off line for repair. Also there are better radar systems for such a situation e.g. SMART-L (

      Something more for speculations:
      – Sri Lanka was within range of MH370. The Tamil Tigers were defeated a while ago.
      – Philippine rebells – wrong direction or to Indonesia?
      – Other rebells groups …
      – hypoxia e.g.

      • Sorry, but I don´t think there is a conspiracy. Some guys half asleep in the middle of the night in peace time with nothing happening saw a strange echo on their screens. I´ve seen a flock of birds make an echo on a radar, funny echoes happen all the time, esp if you don´t have a billion dollars worth of computer gear to sort them out, and Malaysia isn´t a rich country. I suspect the military didn´t realise what it was until the initial search came up empty,

  2. Not to increase speculation (I am not working in aviation and know practically nothing other than what I read through my life because of wide interest in sciences and data), I just want to provide another perspective for people who can use it productively. I was following details of this MH370 accident closely partly to escape from other severe problems keeping me from sleeping, So I am not so overwhelmed like most other writers about the final outcome, too.

    Usually I am considered an expert in human consciousness (I am not a doctor, but also a tech geek in the field), and someone drew a parallel with a previous Helios accident, yesterday. It got me thinking about the physical consequences of slow decompression (especially since the proposed AD of Boeing referred to the SATNAV, or similar system).

    In my opinion it is possible for someone clued up enough to survive slow decompression and the effects thereof, and still be able to somehow use the Autopilot to try to overcome the technical problems and try to return “home”. After injury, perception is likely to last longer than higher motor abilities, including speech. It is very likely that such a person would anyway have suffered a stroke, and thus would not be able to talk normally, thus the other pilot’s opinion that there was only “mumbling” over communication systems. Normal people would have thought that they may be drunk or sleep-drunk. The transponder recording of the last few minutes after it was cut off was from another receiver, too. Where was that? The transponder then seems like it was not calibrated for position and the last data entry of that list was NNE of Shenzhen!! That is in China, north of Hong Kong and (incidentally????) on the initially planned path, although the data somehow does not make complete sense. I initially thought the Chinese might have decided to shoot the unidentified object down at very high altitude, in the early morning hours, after all communication from it ceased and they were paranoid enough for such behaviour in the past.

    But after the more information forthcoming this morning I also think the very sick pilot might have tried in his post-stroke delirious state, to put something back on, and that the second transponder was either also damaged or he could simply not concentrate enough to get it working properly to send useful data. I read somewhere that he was last seen flying at 3—4000 ft over the Strait of Malacca by several people. That is about 1000 m high. What about radar on the OTHER side of the Strait of Malacca? What about transponder reception there? How high are the terrain / mountains there? What are satellites showing.?. What is the possibility that the last few minutes of strange transponder-recordings was after a crash over land, that started working due to the damage of the crash, but with botched data? Or did he keep on flying into the Indian Ocean?

    I still have enough faith in tech geeks to not believe any story of terrorism or other criminal activities! Something happened to the plane on its way up and the aviation people cannot make sense of it because they do not know the extent of human capacity after such injury! NOW I will appreciate the info from the black boxes!

  3. Could it have been shot down? SAM?
    This might explain why the Malaysian military is doing the hippy hippy shake and might explain the fire the one kiwi oil rig worker reported.

  4. The latest seems to be that the military did not track the aircraft, however, a New Zealand Oil Rig Operator claims to have seen some flames in the sky 200-300 KM south east of Vietnam (looking on the map, seems near some islands between Vietnam and Brunei (not sure if it still counts as the Spratley Islands), this would be in the ball park area of their route.
    In the case of fire….. terrorism, fuel tanks…..cargo?

    • Has anyone looked at the home built B-777 flight simulator in the home of the captain of MH-370? What missions did he ‘fly’ and were they saved on the hard drive?

      • The authorities did check his ebay account and spotted an unmarked twin engine widebody plane for sale in an undisclosed Asian Pacific country.

        • Offcourse I do wish to respect the sensitive nature of the recent events and do not mean to offend/hurt anyone with this lighthearted comment

  5. A slow decompression incapacitating the crew and passengers could be a viable theory and if around the same time an electromechanical fault failed the radios, no one would have turned the auxiliary ones on precisely because they were incapacitated. The other theory is just intentional tampering by someone with an acute knowledge of the aircraft system. Not likely to be an action of one person, several people could be involved both on air and on land. This is a spectacular disappearance and I hope it brings out the absolute best in international investigation.

  6. This is so weird. Decompression wouldn’t explain switching off the transponder, an explosion over water would leave floating debris. I supose a hijacking gone bad, like United 93, could explain the diversion, ending up splat in the jungle somewhere. Right now my money is on an alien abduction. Please, just kidding.

    • No candidate Hijacker(s) – if relevant ?? – would rely fully upon the improbable ability to physically master/subdue PIC + Co-Pilot to willingly fly the aircraft to some designated airfield … meaning this : screening the list of passengers, did Malaysian Authorities or Interpol spot one or more individual(s) onboard MH-370 known to successfully have undergone 777 type flight training ? If YES, that would certainly shed some new light to this enigma ??

  7. Seems to come up with some deliberate actions to turn off all comm- go to lower altitude- and change course to a ‘ deeper ‘ part of ocean.

    IMO- few laypersons could do that on their own re turning all the switches needed just to shut off all comm ACARS, etc.

    Appears to be a non ‘ accident ‘

    Who or why and where are they now ??

  8. So we are monitoring everything, recording license plates crossing each intersection, big brother is watching our every move with the GPS chip in our phones. But somehow something that is tracked and has a transponder disappears, even though it is within radar range of land.

    It seems crazy in our day and age, but what a riveting mystery, although quite sad because of all of the souls on board.

  9. I have seen in the media, aviation blogs and other websites the focus on this SATCOM related Airworthiness Directive (AD).

    Just so everyone is aware an Airworthiness Directive, while issued for a potential unsafe conditions, does not mean that a catastrophic condition is likely to immediately exist. The AD states that the condition, if left uncorrected, could lead to the fuselage skin not being able to sustain limit load leading to an explosive decompression event. It sounds bad (which it can be) but the statement is there to state the justification for the AD. The criteria which is used to determine potential safety issues is conservative and is rigorously applied in a partnership between the FAA and Boeing in this case under 14 CFR 21.3.

    If the issue was an imminent threat the FAA would have issued an emergency AD.

    Even though the FAA only issued the AD on February 18 the original service bulletin was released by Boeing in September of 2013. It is likely that the issue has been known for longer than this. The pattern for these things is usually:

    1) The operator or airframer discover the issue.

    2) The regulatory authority is notified.

    3) The airframer works on a solution for the problem. Usually there is a interim and terminating action. This can range from inspection programs, airworthiness limitations or repairs to name a few.

    4) The regulatory authority starts the AD process with a notice of proposed rule making (NPRM). The regulator takes public comment about the proposed rule. In this case it is an AD.

    5) By this point the airframer releases their solution to the problem. It is usually after this point the regulator releases the AD.

    It does not always work like this and can vary on the severity of the issue and other factors.

      • I guess I should have made it more clear that my point was to say that a catastrophic failure due to an issue addressed by an AD was unlikely and ADs are routine.

        • More unlikely than the disappearance of a whole Boeing 777 with 237 people and a possibly deranged pilot on board? The AD is not necessary for my “theory” of decompression, it just fits the puzzle relative perfectly… Is it necessary to be followed by catastrophic / explosive decompression, or can a breech cause a slower decompression and leave the plane still able to fly, albeit without much ability to communicate via satellite (amongst others)?

          • Your theory still doesn’t explain why the transponder stopped transmitting data. Once it is turn on it needs no human intervention unless a squawk change is assigned by ATC.

          • CNN is now reporting the wreckage may have been found.


            Apparently a Chinese Satellite took pictures of the possible wreckage on Sunday morning, and then analyses to be certain of it. They still have not confirmed this is the actual B-77E wreckage.

            “The images were captured on March 9 — which was the day after the plane went missing — but weren’t released until Wednesday.

            The Chinese agency gave coordinates of 105.63 east longitude, 6.7 north latitude, which would put it in waters northeast of where it took off in Kuala Lumpur, Malaysia, and south of Vietnam.”

            If this is the wreckage, then all the reports of it going back over the land mass is in error. The airplane was on or near its intended course.

    • There is a report of a internet feeding frenzy (they have a cool term for it like crowd sourcing) but the upshot was they found an image of a 777 in the water.

      Amazing how good those satellite picture are with their 10 meter resolution from space!

      Lets be serious.

  10. Has the report of the Chinese Listening Post overhearing a message saying the cockpit is “breaking up” been found to be invalid. has stopped talking about it, and it looks like the mods have taken down the post. Anyone here heard more of that?

  11. A fisherman has found a liferaft off port Dickson a southwestern port town
    See yahoo for more details.

  12. BBC reports that possible wreckage is found on satelite images by the chinese.

  13. And we can see all those cool faces in the surface of Mars, well until the resolution is upped and then dang if they don’t just become something else.

    • For a plane to go stealth and flying off in different direction was a action by one of the pilots. Last month a co-pilot on the Ethopian 767ER diverted the plane to Geneva. Also was thinking of the Egypt 990 flight that crashed on Oct 31, 1999.

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