Air France plane missing?

[Gabriel]

Guys, as I've said I'm no convinced, but the idea is not just a jetissonable box, but one that floats, and one that has a radio beacon.

The ones in AF had the radio beacon, but the electomagnetic waves just don't like water for a propagatio mean. The radio is useless under the water, but is unbeatable on the surface.

There is a constellatio of stellites minitorig the ELT frequency worldwide 365/24. Had the recorders of the AF remianed on the surface:
- It would have been known that the airplane crashed almost immediately, and not hours after it didn't honor its schedulled landing time.
- There would have been a precise location of the crash almost immediately.
- Uisng radio homming, a boat, helicopter or amphibian airplane could have bee immediately launched directy towards the recorder (and hence, as a side effect, to the general area of the accident)
- The boxes and first debris would have been found the day after the crash (from the air), and retrived as soon as it takes to get the propper equipment there.

[Evan]

Guys, as I've said I'm no convinced, but the idea is not just a jetissonable box, but one that floats, and one that has a radio beacon.

The ones in AF had the radio beacon, but the electomagnetic waves just don't like water for a propagatio mean. The radio is useless under the water, but is unbeatable on the surface.

There is a constellatio of stellites minitorig the ELT frequency worldwide 365/24. Had the recorders of the AF remianed on the surface:
- It would have been known that the airplane crashed almost immediately, and not hours after it didn't honor its schedulled landing time.
- There would have been a precise location of the crash almost immediately.
- Uisng radio homming, a boat, helicopter or amphibian airplane could have bee immediately launched directy towards the recorder (and hence, as a side effect, to the general area of the accident)
- The boxes and first debris would have been found the day after the crash (from the air), and retrived as soon as it takes to get the propper equipment there.

To survive the impact of a crash into terrain, the flight recorders have to be housed deep within the fuselage. To eject them would require a lengthy mechanism. Based on the condition of the located wreckage of AF447, do you think any such mechanism could survive the impact and then function?

If the system is to eject the boxes before impact, I still don't understand how that can work reliably, not to mention safely (see P3's comment).

I think it's a bonehead idea.

[APS]

FDR/CVRs are a relic from an age where information had to be physically collated and then ferried to another location. The sophistication of wireless data transmission (both in speed and bandwith) has made gargantuan strides since recorders first became the industry-standard approach.

Countless other aeronautical systems have been revolutionised - from the prop to the jet, from mechanical linkages to hydraulics and electrical actuators, from direct pilot input to sophisticated FADEC and FMC interpretation.

The recorder is, in my opinion, the technological dead-end of solid-state deployable hardware pieces. There's only so much you can do to make a shoebox easier to recover from the bottom of the ocean floor or on top of a mountain.

It's time to think outside the box and the solution which promises the most return for the "least" development of "new" technologies is wireless data transfer.

[mfeldt]

First, it should be pointed out that AF 447 does not remain a complete mystery. Findings were made. Much is known, and I feel somewhat confident that we have learned enough from the investigation to determine the probable cause and prevent another occurrence. Of course, these cannot be considered conclusive findings and elements of the mystery will never be known without the boxes.

It is however unclear, if much more will be known with the boxes...

Suppose for a Minute that an on-board fire was involved at some point in the sequence, even if it is unlikely in the context of 447. Would the boxes tell anything about the cause of the fire? Or, if the fire was starting the sequence of events or erupted later-on?

At best, the boxes would reveal if indeed the failure of the pitots stood at the beginning (or if the tail suddenly broke off, as speculated earlier in this thread), but if these single root causes don't exist, even the boxes may not finally solve the riddle..

m.

[mfeldt]

Maybe you could devise a way to release the media instead of the entire unit, after a crash—something small could be mounted up on top of the fuselage near the satcom antenna or in the fin (that always seems to show up), some kind of simple, solid-state memory-card recording updated every few minutes from the DFDR and CVR and designed to float to the surface, and attached with fasteners designed to oxidize and disintegrate in salt water, or to release at a certain pressure depth. Maybe just a USB stick with a flashing LED on a boating keychain.

That indeed appears a simple and practical solution.... Why not distribute a few USB sticks across the plane - one in the tail fin, one in each wing, hell, they are so cheap you can put one in every seat - and update them with the latest data from the recorders every few seconds? Surely, at least one of them would be recovered...


Where can I apply for patents?

m.

[Gabriel]

To survive the impact of a crash into terrain, the flight recorders have to be housed deep within the fuselage. To eject them would require a lengthy mechanism. Based on the condition of the located wreckage of AF447, do you think any such mechanism could survive the impact and then function?

If the system is to eject the boxes before impact, I still don't understand how that can work reliably, not to mention safely (see P3's comment).

I think it's a bonehead idea.

Evan, as I've said (many times now), I'm not convinced, so don't ask me.

However, the reasons I am not convinced are in part what you've said above, plus the logic of the "eject" decision (to ensure an eject when it is needed, and to assure a non-eject when it is not wanted), plus the need to fail-safe the system so the plane is Ok to keep flying safely after an unwanted eject, and the risks and costs of carrying pyrothecnic devices in a plane (sure, the military have ejection seats, but they require a lot of maintainnence plus hard time shelf life, which is a lot of cost, and the logic is the pilot's logic, not an automated one, and they are willing to accept some risks that the civil aviation is not).

That the box would be much more difficult to find in the bottom of the ocean or floating if alone than if attached to the wreckage is NOT a reason for my doubts, because the whole system is concived so as the box ejects, floats and emmits a radio signal (something that it cannot do brom under the water) that would make it much more easy and quick to locate and retirve (and to know that there was an accident and that there's a box to locate to begin with) than if submerged even attached to the Titanic.

[Evan]

That indeed appears a simple and practical solution.... Why not distribute a few USB sticks across the plane - one in the tail fin, one in each wing, hell, they are so cheap you can put one in every seat - and update them with the latest data from the recorders every few seconds? Surely, at least one of them would be recovered...


Where can I apply for patents?

m.

Uh... the patent office I reckon.

But hurry because solid-state silicon memory arrays for 'black boxes' are already in development. The detachment / floatation / ELT aspect is the problem to be solved.

[dezso3]

Blocked Pitot tubes on Air France Flight 447

I was just wondering about the Air France Flight 447 disaster, is there any possibility whatsoever that the black boxes, the flight data recorder and the cockpit voice recorder, will ever be found? And also, it has been speculated that the plane careened out of control when the autopilot disengaged due to blocked Pitot tubes providing conflicting airspeed information to the on board computer. What I don't get is that if the Pitot tubes are malfunctioning, then why isn't there a backup GPS system on the plane that connects to a satellite which can relay its airspeed back to the on board computer?

[MCM]

Dezso,

May I suggest you read back through the history of this thread... you'll find your questions have been discussed at length.

A quick answer for your GPS/Backup question - GPS groundspeed is already displayed to pilots. However, remember it gives you groundspeed, not airspeed, and unless you happen to know (to within about 15 knots) the current wind speed, then its next to useless. Its another piece of information, and particularly useful if you are trying to make an approach to landing without airspeed info - but largely useless at altitude.

I think we'll find this is not a simple "loss of airspeed information" issue... my gut feeling is it will involve the way the airbus aircraft deals with the loss of pitot information and how it displays it to the pilot, as well as pilot training... but we'll wait and see.

[Gabriel]

MCM, why would you care for 15 kts of wind when the difference between the MSL density and the cruise density will make the GPS speed and indicated airspeed differ by some 200kts?

[MCM]

The 15 kts was just an arbitrary figure based on some rough buffers between cruise speed and stall / overspeed. Certainly not a precise figure.

The effect of altitude making GPS vs airspeed incorrect can be predicted, and could be incorporated into a "gps based" backup speed system... so it could be overcome. On the other hand, if the wind was constant, I can simply look at my flightplan which gives me cruise mach number, as well as the planned groundspeed based on that wind. If the wind is accurate, that groundspeed will be within a couple of knots - certainly close enough to use as a guide. None of these methods can, however, account for variation in wind... where 15kts or so could put you far enough out to cause problems.

As you correctly point out - just using the groundspeed readout alone would be rather useless.

[Gabriel]

The effect of altitude making GPS vs airspeed incorrect can be predicted

Right. Do you still carry the CR6 in your flight bag? (enter TAS, pressure altitude and OAT, slide the round dial, and voila! Here is your IAS and M).

Yes, if you can trust the staitc ports and RAT probe, you can make IAS from TAS.

But an unreliable airspeed can be the result of a faulty pitot or static system, so you can't immediately accept the altitude reading. Now the GPS WILL be an excellent crosscheck or backup for altitude.

[MCM]

When I say it can be predicted, I was talking in the concept of a backup airspeed computer system like was suggested. I think we're on the same side of this argument - that a GPS based airspeed backup system is impractical.

My 15kt comment was just one of the problems with using GPS as a backup - the others you have suggested are just as valid, particularly unreliable temperature. Temperature probes are thought to be more prone to blockage than Pitot tubes - although I don't think it has been proven. All came about when there was a number of issues with GE engine flameouts (which appears to have been solved).

As you say... static information can also be misleading if there were icing problems there - although it is a little more unlikely given the way the static system is set up.

I agree that GPS altitude information could be useful as a backup.

As for the CR-6 - I carry a CR-3 in my flightbag, although its probably covered in cobwebs by now. Whether I could remember how to use it is another issue . It might surprise you (it certainly surprised me) that a number of our crew do still carry one in their pocket and use it on a day to day basis.

[Highkeas]

................ is there any possibility whatsoever that the black boxes, the flight data recorder and the cockpit voice recorder, will ever be found? ...................

Yes - otherwise the French would not be soon starting another search.

[EconomyClass]

Yes - otherwise the French would not be soon starting another search.

Hmmm. I thought there was a bit of PR in these searches. I think there's a push on them that comes from more than their own belief about the probabilities. Their reputation has an ugly blot on it, and playing mere odds might make it worse. It could even convince some people to never accept the French option for getting places. I don't think you have to use French aviation to get to the most popular destinations. I know from here to Bulgaria there are at least a dozen options without a French plane involved.