News and theories about the missing Malaysian plane

Angelique,
How does one describe a "normal" accident?

 

I still don't see any reason for assuming there is malpractice involved in the loss of MH370. Earlier there was confusion about the several hundred miles separating the Chinese-detected pings from the Australian-detected ones: the Australian ship has had repeated events and is in the most-likely location, AFAIK the Chinese ship has not had a repeated detection event. The Chinese are not yet in the habit of admitting they're mistaken so the absence of such an admission is no message at all; many experts dismiss it as an emmission from another ship in the area.

So it is likely that the Ocean Shield is on to something. The weak intermittent nature of the signals are making it difficult to reduce the search area to a manageable size, it is 75,000 sq km according to The New Straits Times

 

I agree there is, by definition, no such thing as a normal accident but I understand that English may not be Angelique's native tongue.

It's not certain that it's an accident yet, that's my belief but I've been wrong before. There seems to be some odd aspects - the misinformation from Malaysian officials being by no means the least. In typical accidences there is a MayDay or Pan signal and the plane goes down close to its last known location. A "goodnight" message followed by an airborn ramble over much of the globe is unusual. In flights over water there are often long periods when the plane's location is unknown but much of the anomalous flight was over Malasia and certainly within reporting range until the last segment.

"Breaking news" says they are now getting continuous pings from 2 separate sources that are compatible with the CVR and FDR. I assume the two sources are close enough apart to come from a crashed plane but far enough apart to indicate breakup.

 

Over what range would it be possible to detect these signals ? It seems to me it must be considerable, I can't imagine they just happened on the right spot, and the range is just a few kms.

 

I heard the range is several miles. If that's a "straight line ideal conditions" range then it would be reduced by great depth and other considerations. That range seems a lot but it would be necessary to reach a sensor close to the surface from a few miles down on the bottom of the ocean.

Water is a good conductor of sound energy but suspended solids, underwater topology and thermal layers might absorb, reflect or refract the signal. I'm not sure how much power that range would require but that would be the final arbitor of battery life.

They don't seem to be sending down the submersible as soon as a ping is heard so my guess is reception is poor and they want to have multiple detections and maybe a chance to triangulate the signal source before they get into that phase.

One of the things that bothers me is some of the stories about other underwater devices that might be using the same frequency and confusing the issue. This is not my area of expertise though . . .

 

As I understand it the ELT is an emergency locator beacon, one is attached to the Flight Data recorder (FLD) and another to the Cockpit Voice recorder (CVR).

 

Do signals travel better in colder water ? Or is that a terribly naive idea ?

 

Angelique,
No offence, I believe I better understand what you mean by "normal" accident. Thank you AK.

AK,
The only correction I would make is the ELT stands for Emergency Locating Transmitter, again thank you.

Mr E,
Cold water does reduce attenuation but not as much as the cold battery reduces power.

I believe the signals can travel over longer ranges (numbers unknown) but the media have also been reporting hugely different distance figures and confusing signal sources and origins, the number of ELT's on board, etc. It reminds me of when the Berlin Wall came down, media were reporting consistently of the falling of the 3 foot barrier... 3 meters not 3 feet. Glaring, idiotic, even stupid really. Don't under estimate the potential for miscommunication, at any level. It's the number one failure of Search and Rescue.

 

Well, you are right, media reports are notorious for inaccuracies. It reminds me of the old saying that there are two things in the newspaper you can reliably believe, the date and the price ! Even that isn't always correct, a while back the daily paper here appeared with the wrong price on the front page, it was the saturday edition that is normally dearer than the midweek.

 

Every story I've ever read where I knew the reality, was misleading in some way. I think it's what happens when reporters and/or journalists try to report on things they don't necessarily know anything about.

 

Good question actually! Sound waves travel faster in a warm medium and can be refracted where temperatures vary. This change their direction, scatter them -diffusing the signal - or even focus it so it can be detected at great distances than normal. This pressumably explains why the signals are fading in and out.

Light does the same, producing the mirage "lakes" over road surfaces in hot weather.

Sonobouys that are be dropped into the ocean to detect subs and beacons lower sensors to considerable depth to get below the layer of warm surface water.

 

There are such things as "normal accidents" amazingly enough, even with aircraft. Once you look at the statistics, patterns quickly emerge, such as locations of incidents, compared to a reference, such as the runway, outer markers, percentage of mishaps on cross wind legs to finals, impact with terrain and it's relationship with references, etc. From this the most common "incident" would be pilot error, which is magnified by the law, being that the pilot is in charge and responsible, so there's where the blame will fall.

Typically, a mistake is made on approach or takeoff, which is compounded by another error or oversight, which makes the situation critical and lack of time or panic set in and more poor decisions are made, resulting in the "spiral of errors" commonly found in most incidents. A classic example might be forgetting to lower flaps on takeoff. The pilot rolls off, starts to rotate, cranks her up and and stall warnings start going off. He looks around realizes he's missed the flaps and he hits the throttle, hoping to power out, but without the time or altitude, he stalls, the nose comes down and he hasn't the altitude to recover or time to deploy the flaps and he augers her in.

Flying into terrain is also a fairly common thing, though becoming less so with the latest avionics. In spite of training, pilots like to rely on their flying ability, so spatial awareness and ignoring the instruments has caused many an aircraft to park on the side of a mountain.

20% of aircraft crashes are mechanical failure of some sort. Over 50% is pilot error. Weather and sabotage are both about 10%. The remaining percentage of crashes are "other human errors" such as air traffic control mistakes, fueling mistakes, etc.

Simply put, the most common or normal aircraft accident is Controlled Flight into Terrain (CFIT), where as a perfectly fine aircraft is flown into the ground, usually unintentionally. They're just flying along and boob, the FVR stops, as does the aircraft. The 757 Cali accident (American Airlines 965) is a classic example of this, though some conflict among the flight crew existed, they bounced a 757 off a mountain, descending into the pattern. Over 60% of commercial aircraft crashes are CFIT, making this a "normal accident".

Recent news about the Australian ship's looking for the failing pings, suggests they've gotten grossly lucky and will be able, in spite of my earlier suggestion, to find this wreck site fairly quickly. The latest news has the search area now below 600 square miles, which is manageable. I think the Australians are "on it" and will get a rough triangulation in the next few days, further reducing the search area. By early summer, we should have some images of the wreck, if not have pulled up the FDR and FVR too.

 

Once the plane lifts off with flaps retracted there is no hope, the ground effect that got you up off the ground ceases, the plane stalls, turbines need too time to spool up - your fate is sealed. AFAIK even if you have lots of runway left you can't put it back down safely. Takeoff and approach/landing are the riskiest parts of a flight as can be seen at Commercial Aircraft Crashes.

Par is right, pilots can get overloaded and miss a checklist item. Automated checklists are appearing and should help to reduce the workload. Could they go a bit further and actual prevent mistakes? Would the pilots accept that?

Air traffic controllers often leave the pilots insufficient time to complete procedures, some monitoring of their performance would at least get their attention, although they too are often overloaded and working with antiquated equipment.

 

when I worked as an engineer in the commercial aircraft industry over 20 years ago, the statistic listed the cause of 78 percent of all accidents directly attributed to the flight crew. That means it was 3 times all other causes combined; weather, bad maintenace, airtrafic control, etc.

As part of a follow up study it was found that when a warning beacon goes off, 50 percent of the time the flight crew does exactly the wrong thing to correct it. This does not always result in a crash, but it usually does if their response to an engine failure for example, is to cut the fuel supply to the good running engine, it usually does.

Since than the aircraft manufactures have installed more and more automated systems to take those actions away from the flight crew. If there was only one correct response, the modern systems do it automatically. For instance when an engine fails or flames out, the only correct response is to move the other engine(s) to full throttle, and trim the tail for the asymmetric thrust. The flight control system does this automatically so it leaves the crew to concentrate on flying the airplane.

This no doubt has reduced the number of accidents caused by the crew. But sometimes those cleaver pilots manage to figure out how to by pass the safety systems and create an emergency anyway. There was a commercial flight out of Los Anglese in a big twin engine 767 a number of years ago, they have a duel redundant fuel pump system, and it takes off with all four fuel pumps running during critical climb out. Once a plane leaves the LAX runway it very quickly ends up over the Pacific ocean, in this case at about 2000 ft they get a cautionary system warning that one of the fuel pumps had low fuel pressure. the correct response was to do nothing but fly the plane. But the head pilot, Gods gift to humanity, quickly takes control of the institution, reach up and pops open a locked overhead panel cover to expose the fuel pump circuit breaks. These breakers were designed so only one can be cut off at a time, you have to pull the lever or tab out, and than rotate into the new "off" position. somehow this wizard of smart had practiced using his thumb and forefinger on one circuit breaker, and his third and pinky finger on the other (Boeing human factors engineers has assumed the two circuit breakers were too far apart to do this), and he managed to flip off both fuel system circuit breakers at the same time, cutting off the fuel supply to both engines.

Of course when things suddenly became silent, and their 600 ft/min climb out reversed in a free fall dead stick glide, the crew imminently when into in-air engine restart procedure. Fortunately the crew managed to get one engine restarted 700 ft above the Pacific, leveled off their flight, and than got the other engine restarted, and managed to go on to their destination airport, albeit a bit red in the face. I always wonder what all the passengers in the back were thinking see the ocean coming up on them. After a big investigation, the pilot got fired of course, and all of the other flight crew personel were forced to do more in-air emergency drills in the flight simulators.

So this proves it is impossible to make something fool proof, because fools can be very clever.

 

Having followed a series of TV aircraft accident analysis programs I notice that in the "pilot error" crashes with some exceptions the crew became overloaded with things that they either weren't trained for or couldn't handle simultaneously, in many cases because something was changed at the last minute like the runway, or ground control threw a curve at the last minute and they forgot a step in their checklist. Sometimes they were just plain exhausted but flying schedules that did not permit them sufficient rest.

There were one or two cases where the crew did not receive training to work together as a team so the co-pilot watched as the captain crash the plane and made no move to take over. This was a cultural thing in a couple of cases. Crew disorientation came up once or twice, for example a Russian crew did precisely the wrong thing when flying an American plane; they had trained Russian planes in which a critical instrument operated in the exact opposite sense of Western practice and their training took over.

A modern plane is an appallingly complex machine with a massive array of instruments not often arranged in confusing and arbitrary ways. Human engineering was one of the things I studied in a long engineering career, much of it in Aerospace, and some of the cockpit layouts I have seen suggest that airplane manufacturers have adopted the science rather recently.

One thing I quickly learned as my early designs were built and deployed in hundreds or thousands was, always investigate a problem with the mindset that it was not the operator or the installer. I had to learn that the hard way by finding out I was embarrassingly wrong on my first assumption. I also learned a lot about how different things are at the pointy end in the field.

Yes there are indeed fools out there. One wonders about a training program that can allow them to take charge of a plane. But accidents are investigated by people who work for the system and are often trained by the plane manufacturers. Whenever the pilot does the wrong thing, it is so easy to write pilot error and close the investigation. Stupidity of the kind you describe doesn't come up often IMHO. Where was the co-pilot while breakers were being tripped in a panel that wasn't supposed to be touched? Why are breakers designed to pop automatically designed to be popped manually wtihout a tool of some sort? Did the pilot have a key? Why? Lots more questions can be asked here.

When a machine fails that is not the end of the investigation, the job continues until the reason is discovered. The same standard needs to be applied to human failure. The causes are often similar: stress, lack of maintenance (sleep), poor installation (lack of training), incorrect part (trained in a different plane), wrong materials (wrong person for the job) and so on.

As a long-time system engineer, I know air travel must be viewed as a system, ground staff, air crew, plane, controllers, airports, routes, regulations etc. Each part must be fit, form and function compatible. Unfortunately the system is organic and has grown into its current form over a century. It's pretty good but not perfect. It's not a good idea to blame the flabbyware without first asking why the pilot could not do the right thing when it was demanded of him.