In some ways risk is like an air filled balloon. Early on, it's pretty easy to reduce risk (use your hands to squeeze the ballon to reduce its size). Over time it gets harder to reduce the total risk further. Squeezing the balloon in one dimension results in it bulging out in a different direction.

Sometimes this increased risk elsewhere is anticipated. Sometimes it is not - until it happens. It becomes a trade off, and you can never get it down to zero.

Mh370 may have come about partly through our efforts to mitigate 9/11.

So this question is a balance of risks. On balance, I wonder if the risk of being able to turn a transponder off is greater than the risk of not being able to do so.

I accept that a functioning transponder may not have saved lives, either here or 9/11. We will never know for sure.

But we would know what had happened in real time. With 9/11 it might have permitted the shooting down of UA93 had passengers not taken things into their own hands. A hell of a decision, but what would you have authorities do if it was headed towards a major population centre. We would likely have the recorders for MH370. And the sure knowledge you couldn't disappear may act as a deterrent.

As the world moves into a period of higher risk, the (acknowledged) risk of not being able to turn off an electrical item may actually now be the smaller risk.

It would not have saved lives, that's obvious based on the fact that its an aircraft you are talking about.

Once the aircraft has been commandeered by miscreants, there is always going to be bugger all you can do about it until the aircraft reaches the ground in one form or another (i.e. whether they crash it or a government blows it out of the sky.... the result in terms of the lives of those on board is the same).

I suspect rather than creating stupid fire hazards by hiding away equipment, you will find the more obvious solution to MH370 is staring you in the face .... improved profiling and psychological monitoring of flightcrew.

Well it could have saved lives if it had been a sufficient deterrent to prevent the "hijacking" in the first place. And being able to track a plane could perhaps help to save lives on the ground. Can we agree that we would prefer to track a hijacked plane than not track it?


It would be hard to think of a less effective measure than this. Psychologically profiling is unable to identify someone about to commit such an atrocity. No psychologist believes this is possible.

Due to the number of incidents, the best data probably comes from looking at mass murderers. Yes in retrospect people will often come out and say the offender was odd or unusual in some way, or had recently suffered a relationship breakdown. But that is very different to prospectively identifying someone in time to prevent an atrocity.

There are certainly some "risk factors" e.g. male gender, feeling isolated, being a bit aloof or awkward among others, recent marriage breakdown, financial problems etc. However these risk factors are so common they define a significant proportion of the population. Does anyone know a male pilot with marriage difficulties?

The risk factors have high sensitivity (i.e. some of these factors will be present in most offenders), but appalling specificity (in that the overwhelming majority of people with these risk factors will not offend). So we can use these risk factors to predict that the next offender will likely be a male with some interpersonal difficulties, but we can't predict the identity of the next offender. They are useful at a population level, but completely useless at an individual level.

This article is a few years old, but is still true today
Dark Matter: The Psychology Of Mass Murder

"Terrorism" used to be about getting a gun onto a plane and issuing demands to release prisoners etc. 9/11 changed that - it was about getting a pilot onto a plane, forcing entry to the deck and taking control. It has probably changed again with MH370.

I would certainly take my chances with being unable to isolate an electrical system than with psychological screening.

Slats11 says:

"I would certainly take my chances with being unable to isolate an electrical system ...".

I suspect, but don't know, that the transponder circuitry itself is remote. All that is local is the line and the switch. And, in my view, even they don't need to exist.

But nobody is talking about the CVR and FDR batteries. Surely none of my detractors think that these batteries are sufficient? I wonder if a power source can be devised using seawater as an electrolyte and dissimilar metals as electrodes.

There was a significant discussion on CVR/DFDR batteries several eons ago on this thread. Not only that but on the choice of frequency, the lack of modulation of the ping with an aircraft ID or last GPS position, and power increases by reduction of the number of pings or by using transponder techniques.

It seems that the CVR/DFDR spec for locator beacons was for finding the recorders in a river or lake. The expansion of transoceanic flight passed by the people setting the requirements until AF447. Now they are belatedly increasing the battery capacity but other 'bright ideas' have not been taken up.

ATSB Updates
 

Some new material posted by ATSB.

MH370

3D map of sea floor (2.2 MB) in search area:

http://www.atsb.gov.au/media/5092636...or_terrain.jpg

Depth in primary search area roughly 2 to 3 km, some deeper, some shallower.

One good reason for having a transponder that can be turned off from the cockpit is it if develops a fault and starts giving bad data to ATC.
AFAIK large airliners have two transponders in case one fails.

Sep 9 update by Duncan Steel, Michael Exner, Tim Farrar et al:

MH370 Search Area Recommendation | Duncan Steel

https://dl.dropboxusercontent.com/u/...09-09_Rev1.pdf

Their best estimate of position at the 00:11 ping is 37.5 S, 89.2 E, very far removed from the ATSB search areas. Their recommendation would further imply a need for another several months of bathymetric survey.

On the other hand, John Zweck, Australian Ph.D. in mathematics does an independent calculation that aligns very well with the ATSB search area. His August update:

http://www.utdallas.edu/~zweck/MH370AugustReport.pdf

(Note: to convert km/hr to knots, divide by 1.852)

Zweck's best estimate of position at 00:11 ping using great circle model is 98:89 E, 27:64 S and using small circle model is 99:16 E, 27:28 S.

These don't account for glide after fuel exhaustion, so are very close to the center of the ATSB Priority search area.

Sep 10 link to Zweck's latest spreadsheet:

Aqqa on MH370

Which rather implies that you consider the risk of hijack on any given flight is more severe than the risk of electrical fire on board. I am not sure that would stand up to statistical scrutiny, probably by a factor of several thousand - even if the "no-off" transponder was a sure fire deterrent of hijack, which clearly it is not.

The mystery of MH370 is frustrating, but perhaps it is better to just swallow that frustration than fit an additional fire hazard in every commercial aircraft just in case it happens again.

As for psychological profiling, I am similarly sceptical about its effectiveness. But at least it is directly addressing prevention. The transponder issue is just helping us find the wreckage afterwards.

Quote:
"Which rather implies that you consider the risk of hijack on any given flight is more severe than the risk of electrical fire on board. I am not sure that would stand up to statistical scrutiny, probably by a factor of several thousand - even if the "no-off" transponder was a sure fire deterrent of hijack, which clearly it is not."

Electronics is my area of expertise. First, low-power devices pose little fire risk. Second, there are hundreds of such devices on any given commercial jet- phones, laptops, etc- which the pilot cannot turn off. Adding one more won't make any difference.
Third, the technology is readily available and cheap. Something like a $150 SPOT beacon could report periodically, somewhat like a transponder. Smart people can work out the details and address legitimate concerns, but it's nuts not to track every airliner in the post- 9/11 era.

OK

The two Mode S transponders on a typical commercial airliner have a 500W plus transmit power!

...so yet another piece of equipment on board. Can we just have a reality check here. There are already means of satellite tracking aircraft. It is just that on this one occasion that means was disabled - possibly deliberately, but we do not know for sure, and if it was disabled by electrical fire then this whole argument gets a bit ironic..

When CVR and FDR became mandatory this fulfilled a clear purpose: Post accident analysis to find means to prevent recurrence. However, adding ever more kit to report on ever more rare events just does not make sense to me.

We have to assess risks and mitigation properly before we add our quick fixes.

Maybe I am nuts, but to me that seems to have been an excuse for adding extra layers of surveillance on just about everything and everyone. Even since that fateful day the risk from terrorism remains one of the tiniest risks an individual (even an airline pilot) will face in their daily life.

Quotes:
"The two Mode S transponders on a typical commercial airliner have a 500W plus transmit power!"

"There are already means of satellite tracking aircraft. It is just that on this one occasion that means was disabled - possibly deliberately"

"We have to assess risks and mitigation properly before we add our quick fixes."

I believe the most powerful transponders put out 250 watts, so you could claim that a pair of them have "500W plus transmit power". However, they transmit brief pulses, so they only consume about 10 watts. They are low power devices. Yes, there are already means of tracking planes via satellite. My point is if hand held devices like satellite phones and SPOT beacons have enough power to communicate with satellites, it obviously doesn't take much power and therefore poses little risk of causing a fire. I have no objection to assessing the risks and mitigating them, smarter people than me can figure out the details. More than a decade after 9/11 I don't see much risk of "quick fixes".

The most powerful transponders are around 600W. And it is the peak power rather than the average which is the risk if the transponder goes faulty - not just to the aircraft but potentially also the local radar environment. It is really important that transponders can be switched off. This is all simple stuff but not really the point.

More than 13 years on and the paranoia does not abate. An endless series of sticking-plaster quick fixes. When it comes to the "war on terror" there is a bizarre lack of perspective. So let's put another piece of kit on board, drill yet another hole in the aircraft skin and create yet another certification procedure (nothing on a modern airliner costs "only $150"). And without any clear idea on whether this would improve aircraft safety or by how much. Because let us be clear, what is proposed here is not a safety feature. This is a "something must be done" and "how hard can it be?" feature.

I agree.... ever since 9/11 politicians and companies selling security products have used the "terrorist" word to validate the introduction of knee-jerk archaic legal powers and obtain finances to fund vast technology purchases.

Its time for the world to act less Daily Mail and more Financial Times when it comes to implementing measures to combat terrorism.... :cool:

The main problem with the MH370 disappearance was that the response to a missing aircraft has not altered for years. Aircraft overdue action is only legitimate once the aircraft is overdue at destination. In the current systems where aircraft are already continually tracked - despite the avionics and comms salesmen claims - an aircraft ceasing to report its position and respond to RT/CPDLC should immediately be treated as an emergency. Even with the loss of secondary being on handoff, the systems could have flagged a possible problem. The Malaysian and Vietnamese controllers should then both have treated the missing aircraft as an emergency and alerted all agencies including the military. The military would almost certainly have responded that they could still 'see' the aircraft. The event could then have had an entirely different outcome.

There is no need for new equipment to track aircraft they all have it. The beancounters try to limit the use of ADS-C as the SATCOM providers charge for each transmission. However, that is no longer the case as both INMARSAT and AIREON (Iridium Next) are offering free tracking services. With AIREON also proposing to track ADS-B (although the capability is yet to be proven). What is needed is procedures to use when the tracking suddenly fails because the aircraft has 'gone dark'.

I would propose that someone at the ICAO level start's looking at the old procedures for missing/overdue aircraft. A start would be an immediate response to aircraft that stop communicating/transponding rather than we wait for the end of the aircraft endurance before we can start anything official.

Malaysian Airlines MH370 contact lost
 

Why not use ELT "the way sea ships" are using them. No need for any el power nor radio relay. They are designed to detach from ship in case of disaster and NOT to be pulled down together with the rest of tail or cockpit. Voila !

ELT's were discussed way back in the thread. The C5 I think had a jettisonable ELT on the tail fin. The ones in current commercial aircraft tend to be fixed in the fuselage, or on life rafts or even as separate manually initiated buoys that the flight attendants can access. Given the thoughts on what happened with MH370 only a detachable external ELT would have given any location of crash as the cabin crew are thought to have been disabled by depressurization. ELTs do not run all the time as they are on an HF emergency frequency so they would only allow easy finding of the crash site.

I can't speak for the C-5, but the P-3 certainly has.

Either way, you're right in that the subject of ejectable ELTs has been done to death.

While it might seem unreasonable to suggest that posters making suggestions like that should read the previous 11,000 posts first, they might pause to consider that in a thread that's been running for more than 6 months, almost every conceivable angle has already been explored extensively.

MH370 Operational Search Update 24 September 2014


MH370



Three-dimensional models of the seafloor terrain


Three-dimensional models of the seafloor terrain

ICAO Annex 12
 

Ian W

Recommend you look at my post No. 8089 that was written way back on March 25, 2014. There is not much wrong or lacking with the ICAO procedures (i.e. Annex 12) for locating missing aircraft - they just need to be followed in a timely manner. My post described the various steps and actions to be taken once an aircraft appears to be missing. This was clearly not done by several involved parties - in particular, the various Malaysian authorities. The Annex certainly does not intend for S & R organizations to wait for the aircraft to reach its endurance before initiating a search. Those in commercial aviation with responsibilities associated with S & R need to gen up on Annex 12 and keep a copy handy at their work stations.