Re: [SystemSafety] MH370

From: Matthew Squair < >
Date: Wed, 12 Mar 2014 08:19:52 +1100


Just to add that large passenger aircraft do have onboard emergency locator transponders, a mix of fixed (airframe mounted and possibly g switched) and portable (cabin and raft located). Over water a portable (buoy style) maritime ELT is carried onboard but its down to the crew to deploy it. Unfortunately if the maritime ELT goes to the bottom with the aircraft while it may activate, the radio signal is unlikely to get through.

Sonar pingers are fitted to FDR and CVR, but with underwater acoustics you need to get within range, on the order of a couple of km, and just because you can hear them doesn't necessarily mean you can locate them easily; currents, ambient noise, thermoclines, turbidity, terrain shadowing or wreckage can make the job very difficult.

Matthew Squair

MIEAust, CPEng
Mob: +61 488770655
Email; Mattsquair_at_xxxxxx
Web: http://criticaluncertainties.com

On 11 Mar 2014, at 11:41 pm, David Crocker <dcrocker_at_xxxxxx

 Large commercial aircraft already transmit their position and other parameters to other aircraft, via mode S extended squitter, and in some areas (some USA airspace AFAIR) by ADSB over VHF data link. If aircraft recorded some of the data they received from other aircraft, then there would be the possibility of determining the last position of an aircraft before catastrophic failure from the recordings stored by other aircraft in the vicinity, even in areas where there is no radar cover. This could speed up the recovery of the FDR and CVR.

Whether this would be viable depends on the range at which data can be received from other aircraft, and the density of aircraft in the airspace.

David Crocker, Escher Technologies Ltd.http://www.eschertech.com Tel. +44 (0)20 8144 3265 or +44 (0)7977 211486

On 11/03/2014 10:07, Chris Hills wrote:

  Memory may be cheap but an EPIRB is self-contained. It needs no external connections or wiring. No point in adding any complexity (weight, power requirements, connectors, wiring and systems in the aircraft etc). With no connections to the aircraft wiring or power supply the reto fitting is far easier, cheaper and the system is more cost effective.

As it is only going to be needed for locating aircraft that have sunk it only needs to be on a mount at activates at a depth of say 10 metres and a life of 24 or 48 hours. 24 might be a bit short if it is in the middle of nowhere and the weather is bad.

Once you have found the EPIRB the aircraft will not be far away compared to the current search area and that for AF447. Then you can recover the data from the FDR and CVR.

*From:* Matthew Squair [mailto:mattsquair_at_xxxxxx

Yep, like an EPIRB. But if you're going to do that, well memory is cheap.

Matthew Squair

MIEAust, CPEng

Mob: +61 488770655

Email; Mattsquair_at_xxxxxx

Web: http://criticaluncertainties.com

On 11 Mar 2014, at 8:13 pm, Chris Hills <safetyyork_at_xxxxxx

 Actually you don't need a detachable FDR or CVR. All you need is a detachable simple distress beacon with a life of 48 hours. If you can find that it would narrow the search field to say, a 10 mile radius, rather than thousands of square miles. Then you can find the wreckage and the black boxes far faster.

A small distress beacon would be smaller in size, mass and complexity, very cheap (comparatively) and easier to mount.

Regards

   Chris

*From:* systemsafety-bounces_at_xxxxxx mailto:systemsafety-bounces_at_xxxxxx
*On Behalf Of *Matthew Squair
*Sent:* 10 March 2014 23:28
*To:* Peter Bernard Ladkin
*Cc:* systemsafety_at_xxxxxx *Subject:* Re: [SystemSafety] MH370

Sure, but over the years there have also been a number of lost at sea accidents where either the FDR or CVR were not recovered or were recovered damaged. Dave Warren's original proposal was aimed squarely at that problem and was for a foam cored blister pack with a simple wire spool recorder and die pack, the concept being that it would be mounted on the external fuselage (around the tail) and popped off in an explosion or impact induced hull over-pressure.

On Tue, Mar 11, 2014 at 9:07 AM, Peter Bernard Ladkin < ladkin_at_xxxxxx

> On 10 Mar 2014, at 22:17, Matthew Squair <mattsquair_at_xxxxxx
>
> Absolutely, nothing is perfect. But would I prefer an alternate to months
of trawling the abyssal plain with a side scanning sonar? You betcha. Especially if it's a very, very cheap alternative.

In the last twenty years, there are just two cases of lost-at-sea I can think of in which evidence from the hull was *not* required in addition to FDR data to determine cause. There are five cases in which in-air disintegration or burning, which are not identifiable from FDR data, initiated the hull loss, and there is one further case in which physical evidence was required to show there was no anomaly (that it was, in effect, murder/suicide). Two against six isn't a persuasive ratio.

I can go through the records to make this definitive rather than "I can think of", if necessary.

The result of a cost-benefit analysis, even for the past, let alone for conceivable future cases, is not at all evident to me.

PBL Prof. Peter Bernard Ladkin, University of Bielefeld and Causalis Limited

-- 


*Matthew Squair*
MIEAust CPEng Mob: +61 488770655 Email: MattSquair_at_xxxxxx Website: www.criticaluncertainties.com <http://criticaluncertainties.com/> _______________________________________________ The System Safety Mailing List systemsafety_at_xxxxxx _______________________________________________ The System Safety Mailing Listsystemsafety_at_xxxxxx _______________________________________________ The System Safety Mailing List systemsafety_at_xxxxxx
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Received on Tue Mar 11 2014 - 22:20:07 CET

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