Air France 447 - On topic only!

[Fear_of_Flying]

Of course, these raw statistics are misleading. In comparing the relative safety of the aircraft design, you have to deduct any crashes that were not due to design or mechanical issues, and only then are these stats useful. For instance, the 767 has had a number of hull loss incidents, but only one crash I am aware of related to mechanical issues, and this was an early ER model with a flawed reverser design which has since been replaced fleetwide. Other crashes were due to 'foul play' and pilot error (not stall-related). These could have involved any airframe. Therefore, despite the raw statistics, I consider the B767 to be among the safest aircraft ever designed.

Hmm, but isn't pilot error also related to the aircraft? Colgan, an extreme case of pilot error, maybe couldn't have happened on an Airbus, for example, which would have prevented flying outside the envelope.

[Gabriel]

That last bit is an interesting idea I don't think we discussed - what if it wasn't the pitot tubes themselves that were faulty, but the wiring? Would that scenario produce the same effect as what the ACARS showed?

The wiring, or the transducers. I guess it would produce a similar effect. A speed disagree is a speed diagree regardles of what link of the chain holds the cause.

[Evan]

Hmm, but isn't pilot error also related to the aircraft? Colgan, an extreme case of pilot error, maybe couldn't have happened on an Airbus, for example, which would have prevented flying outside the envelope.

Well, I did mention there that these were cases of pilot error (not stall related), so no, stall protection issues would not have made a difference on the 767 examples. You have a point in general, and it can be extended to how the systems interface with the pilots, but only in cases where this has been a contributing factor (such as Turkish 1951). In fact, I consider pre-2003 737NG's that have not received autothrottle logic upgrades to be inherently dangerous (but then, how do you know?).

Simple answer, there is no simple answer. To determine the relative safety of an aircraft design, you have to look at these statistics with a lot of knowledge to exclude those which are not related to the aircraft design. But then you also have to look at all the non-hull loss incident reports as well, as some of these could have easily resulted in fatalities if not for the actions of the crew. And then you have to look at the performance of the aircraft safety provisions in these incidences, which also define the aircraft as an inherently safe design.

[Evan]

Meeeanwhile, the debate about live streaming and detachable floating flight recorders continues to brew. I found this recently and haven't had time to go through it more carefully, but it is a BEA feasibility study on these options:

http://www.bea.aero/en/enquetes/flight.af.447/flight.data.recovery.working.group.final.report.pdf

At first glance, it seems more feasible to include additional parameters in ACARS, such as positional and attitudinal data. Voice recordings and the vast array of parameters currently recorded by the static boxes appear to be beyond the realm of realistic SATCOM bandwidth application however. ANd then there's cost...

[Evan]

Incidentally, when more information from the flight recorders comes to light, this is the place to find it:

http://www.bea.aero/en/enquetes/flight.af.447/flight.af.447.php

[kris]

Actually it is the CVR they have located (recovered). They still need to find the FDR.

Silly me, I was expecting to see the rectangular FDR and cylindrical CVR memory units, and thought the media mixed them Since they now have found both, and both are cylindrical... Sorry for the noise.

K.

[Theoddkiwi]

Question though: If conventional lightning strikes near the nose of a plane, what effect could it have on the pitots or pitot transponder units, or the associated wiring (the A330 being a pitot-by-wire aircraft)?

Little to none, most of our lightening strikes are on the nose of the aircraft. The path of least resistance is to run along the metal skin and the frame which is why typical damage is burnt rivet heads.

A typical strike would be hitting the nose by the pitots, then running along the fuselage and out to one of the hoziontal stabs and exit at the tip of the elevator.

Our pilots will review operation of the aircraft systems in flight if they can, and will state that all radios and nav systems are serviceable (if they are) in the maintenance log.

What can happen is magnetic feilds from the strike can be induced into the aircraft wiring causeing a some interferance, but this will be momentary. Systems that are susceptable to or could suffer from EMF are typically shielded which prevent the EMF from interfering with the signal carried in the main conductor.

Modern aircraft feed their Pitot and Static pressure to Air Data Modules which measure the pressure and convert it to a digital signal. These like all aircraft boxes are metal so again naturally sheilded from EMF and lightening strikes.

So EMF interferance is pretty harmless and momentary at the time of the strike.

[Black Ram]

Anyone know if BEA intends to recover the actual pitots and examine them, as well as other parts of the wreckage?

[Myndee]

So what materials about the Bus did they give you to study?
Why do you have a pic of the pretty Steelers A319, if you dislike/fear the Bus?
Sounds like these things are becoming popular in the US.

No materials really, just some facts and things to ponder. Its a few pages back in this thread.

As for the Steelers pic, I just think it is awesome. If someone put a Steelers paint job on a beat up Pinto, I would probably think that was awesome too. LOL...

It does look pretty sweet.

[MCM]

G'day Evan,

Therefore, despite the raw statistics, I consider the B767 to be among the safest aircraft ever designed.

You won't get any arguments from me there!

Oddly enough, I think that its lack of technology (while still having some) is a great example of where we need to carefully consider where we go in the future with machine design.

The 767 is a very flexible aircraft to fly - you can do some amazing things with it - however it is also a very "hands on" aeroplane. The automatics are good but not great, and as such the pilot is particularly in the loop as it will often do things that are not quite what the pilot wants.

In this sense, although it is a little more antiquated, the pilot must be fully involved with the aircraft at all times - whereas with the more advanced machines it is very easy to become complacent because for the vast majority of the time they are perfect.

Something I also wonder is the demographic of crew on the aircraft. Most airlines seem to not have the 767 as an entry level aeroplane, and most are owned by larger, more established airlines. I wonder if the pilot and operator demographic makes it look good.

[Theoddkiwi]

Something I also wonder is the demographic of crew on the aircraft. Most airlines seem to not have the 767 as an entry level aeroplane, and most are owned by larger, more established airlines. I wonder if the pilot and operator demographic makes it look good.

And perhaps the opposite goes for the 737, where many have been crashed by poorly run airlines and poorly trained crews. Many older 737s end up in these sorts of environments which are conducive to bad lower safety standards.

I just read an article in the Australia Flight Safety magazine on the Kenya 737 that crashed 90sec after takeoff. The Captain failed assessments time and time again , had a history of being reckless and over bearing and over confident and had poor understanding of his aircraft, yet he was still given command of the aircraft. Then he killed himself, his crew and his passengers because of all these factors.

It will be interesting to see how A320s stack up in 20 years time being flown in third world countries. The A310 does not have a very good record here.

[TeeVee]

And perhaps the opposite goes for the 737, where many have been crashed by poorly run airlines and poorly trained crews. Many older 737s end up in these sorts of environments which are conducive to bad lower safety standards.

I just read an article in the Australia Flight Safety magazine on the Kenya 737 that crashed 90sec after takeoff. The Captain failed assessments time and time again , had a history of being reckless and over bearing and over confident and had poor understanding of his aircraft, yet he was still given command of the aircraft. Then he killed himself, his crew and his passengers because of all these factors.

It will be interesting to see how A320s stack up in 20 years time being flown in third world countries. The A310 does not have a very good record here.

just the shear number of aircraft in service and the number of years the model has been in service gives it a very high number of incidents as well. however, if you look beyond the raw number of incidents and take into consideration the number of cycles, the "rate" drops.

i think you may have a valid point though.

[Evan]

Something I also wonder is the demographic of crew on the aircraft. Most airlines seem to not have the 767 as an entry level aeroplane, and most are owned by larger, more established airlines. I wonder if the pilot and operator demographic makes it look good.

All the more reason to question the statistics in rating the safety of the design. But I think that the more idiot-proof you make something, the more it attracts idiots, whereas the more challenging something is, the more skill and discipline it breeds. I think the safest designs find a balance point between these two. There's an old C-47 still flying pax around here and I'll bet the pilots never forget to fly it. On the other hand, the 767 has all that space-age technology to assist and provisions for failure that earlier designs lacked. It may provide for the perfect balance of tools and skill, and perhaps that is what makes it so statistically safe.

On the other, other hand, I think the pilots still flying pax on the moody MD-11 are probably as skilled as they come, but I'm still not sure I trust that thing with my life.

OT: MCM, do you/have you flown the more advanced 767-400 and if so how does it compare in terms of that balance?

[EconomyClass]

Is it possible that gee-whiz technology persuades airlines to send planes into the most hazardous situations? As if they really trust the machines more than the people? Then if the people get a mindset of "these planes can handle just about anything", you have a good setup for some sort of catastrophy. Some people trust computers and their networks like that, but I've seen them fail many times for the stupidest reasons. They are extremely fault tolerant. But sooner or later, the scenario that breaks them comes along. I'd say that result is 100 percent certain. If something can break, the scenario that can break it will happen. If you can't log on to your bank account, you at least can breathe while you steam. If you are sitting in a seat on an Airbus, plummeting into the ocean, it really sucks. Your fault for climbing on a plane, I guess.

[Alexandre]

Anyone know if BEA intends to recover the actual pitots and examine them, as well as other parts of the wreckage?

I hear that they want to try to recover all the cockpit, if they succes they will have the pitot.