hetfield

Because it MAY have been a contribution for this accident and other incidents?

rudderrudderrat

Hi DW,
You misunderstand me.
Normal Law is brilliant, the aircraft is wrapped in cotton wool.
Direct Law is beautiful "Handling characteristics are natural, of high-quality aircraft, almost independent of the configuration and of the CG."
Alternate Law is a confusing mixture of both - without "protections" and without the natural longitudinal speed stability the aircraft has naturally.

In the 70s, when I flew L1011s we had CATIII NO DH auto land capability, Autopilot CWS (like hand flying in Normal Law), autothrust Alpha Floor protection (Like VLS).
When the auto pilot was out, she handled beautifully with manual pitch trim.

What forward progress do you think we've made?

A33Zab

Nothing against L-1011, way ahead of it's time but:

Incidents and accidents

As of August 2008, the L-1011 was involved in 56 incidents, including 11 hull-loss accidents (out of 250) with 534 fatalities.

As of June 2011, the Airbus A330/A340 had been involved in thirteen major incidents, including six confirmed hull loss accidents (out of 1140) and two hijackings, for a total of 338 fatalities.

DozyWannabe

Not to mention that the thing's lighter, requires one less donk and one less full-time crew member (which makes it more economical to run). Don't get me wrong, the L-1011 was a fantastic airliner and still has to be matched in some aspects today, but in economic terms it was flawed and sales suffered badly at the hands of the DC-10, which turned out to be another more seriously-flawed gem.

foster23

Thanks for a very easy explanation of all the laws.

jcjeant

Hi,

In my opinion it is the heart of the problem
A plane (was) should be a means of transport which allows to go quickly from one point to another and is relatively expensive for passengers and must be of an acceptable return for its owners (airlines)
A plane must now be a means of transport which allows to go from one point to another (but now the emphasis is no more on speed ! ) and to be inexpensive for passengers and who must have a return to report the maximum possible for its owners (now mainly banks and shareholders)
This is also the other side of progress
Progress is being made in terms of economy and efficiency ..

rudderrudderrat

Hi A33Zab & DozyWannabe,

It depends how you manipulate statistical data. You have to compare apples with apples.

The link below lists fatal events with aircraft type where “A fatal event is defined as 'an event in which one passenger was fatally injured solely due to the operation of an aircraft.' The number of fatalities in each fatal accident is irrelevant in the statistics presented below.”
AirDisaster.Com: Statistics

According to this analysis, B727, B737, B757, and B767 are all ranked as having fewer fatal events per flight than 320 series.

The L1011 is ranked as having fewer fatal events per flight than DC-10, DC-11 or B747.

DozyWannabe

The problem with the AirDisaster stats is that Chris Kilroy is a known Boeing partisan, and revealed some very negative opinions of Europeans and the French in particular in 2001.

Besides that, those figures don't take into account the longevity of each airframe, and the fact that a lot of accidents in new types will occur in the first 5 years of service. Once an aircraft has plugged the line for a while, its "quirks" are known by the piloting communities and they cease to be as much of an issue. It would only be fair to either compare the first decade of service of each, or discount the first 5 years as a statistical anomaly and take the stats from there. Either way it skews the stats in favour of aircraft that have been around for longer.

rudderrudderrat

Hi DozyWannabe,

Page 20 on this Boeing Document is up to 2010. (I can't find an Airbus Document yet)

http://www.boeing.com/news/techissues/pdf/statsum.pdf

Once I've analysed the data a bit more - I'll be able to reply better.

Edit. From Page 20:

Hull loss rate per million departures
rate = with fatalities accident rate / Hull loss accident rate total
B737-600/-700/-800/-900 rate = 0.18/0.30
A320/321/319/318 rate = 0.20/0.33
B737-300/-400/-500 rate = 0.28/0.52

B757 rate = 0.24/0.24
B767 rate = 0.13/0.38
B777 rate = 0/0.18
A330 rate = 0.46/0.46

A340 rate = 0/0.87
B747-400 rate = 0.31/0.62

I can't detect that much difference between B or AB - they are very similar.

henra

If someone tries to tell me that the 727 has a better accident statistic than a modern Airliner, that is exactly the second where I throw the paper away instantly.

FWIW the 747 has a much much worse statistic than the 320 or 737 (especially if you include the older versions).
What do you make of that ???

edit:
Agreed. However the data is only really meaningfull for the 737 and A320 from a statistical perspective.

With the A330/340 and 777 the absolute number of occurences and flight cycles (Not flight hours in this statistic) is too small so that one occurence more or less makes a difference between excellent and not so good. Best example is Concorde from 'safest' to 'unsafest' airliner after one single crash.
When you have got >20-30 Hull losses the statistic starts to become more meaningful.

RetiredF4

Could some expert explain the following part of the
FCOM page

FlightControls Normal Law, 1.27.20 P2 Seq. 001 Rev03

Pitch Control / light mode

Would that not inhibit the trim to move ND when unloading enough (provided elevator authority is big enough)?

further down:

Shouldn´t that have prevented or hindered the THS to move to 13°ANU?

Im familiar, that the described paragraphs relates to normal law. Are those vital features lost in ALT LAW?


A few pages down another one causing headache:
Flight controls Reconfiguration Control LAWS
Alternate LAw Alt 1
Protections
Low speed stability

As IAS was incorrect from beginning and leading to AP /Athr disconnect, and later dropped to 60 kts, could this mode have been activated on behalf of the wrong IAS? How would the ND input by the system differ on behalf of an incorrect IAS (systems gets slow IAS, but actual AS is considerable amount higher, would the ND input be more pronounced then with real lower IAS?
Could this have tricked the PF to counter the system ND input (if this protection was active and the ND input was commanded by the system) by NU SS input and contributed to the high pitch result, when PF NU input overrode the ND input of the Low speed stability protection? Which was then possible, because pitch attitude protection is lost in ALt law?

And what is meant by the term "bank angle compensation is provided"?

I still dont get the whole picture of those law changes and the asociated protection changes or protections lost.

So please be patient, if my questions look uneducated or if the questions have been answered already. And it has nothing to do with A vs. B.

A33Zab

Conclusion: FBW is as worse as NON-FBW?

I can detect a difference, why did they separate A330 with A340?
They are identical A/C apart from amount of engines.

WilyB

... shows statistics valid through December 31, 2004.

WilyB

JC, shareholders are, by definition, owners. Now that we established this, shareholders might be banks, yourself, or your retirement plan. Whatever the case, Airlines are historically a risky investment most of the time.

john_tullamarine

Could you comment on the inclusion of "damaged or missing" radome?

I don't think I saw any comment on this question.

Pitot static performance is dual input - pitot and static.

Apart from blockage pitot performance generally is pretty robust and doesn't give too much in the way of problems.

Static performance, on the other hand, is a bit of a prima donna.

- in the certification phase development of PEC data is a major part of the flight testing program.

- we even go to the trouble of using trailing drogue (cone) static sources to get out of the aircraft's interfering flow fields

- modifications forward of the static source can be a nightmare for PEC effects. I recall one tale about a B52 program where a mod up forward made a BIG difference to IAS during the takeoff - fortunately, the TP had a feeling in the water during the first takeoff and rejected.

- in routine operations, the easiest way to get a massive airflow disturbance which will always cause an effect on the PEC is to have the radome disintegrate ...

For those who like some arithmetic and lots of fancy mathematical symbols, you might like to read reports like this one. (Everything you wanted to know about pitot statics but were afraid to ask ...)

Linktrained

WileyB

Eddie Richenbacher stressed "Reliability" of air transport back in the 1930s. His backers understood that this had to include the then new technologies, Radio Range etc. Others understood that any mishap, and that included off- schedule operation, costs money and ultimately insurance premiums would rise.
"Safety is no Accident"
Newer aircraft became larger, faster, and more productive, and must be kept working to repay their initial cost. And they became more efficient. Staff need suitable training, to get the best from the Capital - it is an investment. Reliability encourages profitability.
( Just think of re-equipping AF with Constellations to do its present work. In 1970 I replaced the fleets of one airline with 400 Yorks, which would not have been subject to Night Jet bans ! )

CONF iture

ISIS is not especially larger than the standard standby indicator, and the standard standby indicator is not more 'unreadable' than the ISIS.

Pretty rare, but I can still remember flying under MEL an entire week or so without it due to a defective trim tank isolation valve.

Never the MAC could have been to 38% after only 3 hours something in the flight, not with the initial very much forward 23% CG at takeoff time. My own estimate would have put it around 32% at the time of the event, but the BEA now mentions 29% ...

If now to have to trim an airplane overloads a pilot, so, something is very wrong with the airbus philosophy. How will cope a pilot the day he has to do it when the system pushes him to lose that practice. Let the pilot trim, it is just more pleasure and SA in the mean time.

Icing maybe or just the unusual 'AoA' for those static probes induced unreliable readings for altitude and/or Vertical Speed ...

Something big is missing in the story : I can't believe 3 guys would have maintained NU inputs for 3 minutes with 3 A/H showing blue blue blue and 3 altimeters going down like crazy. BTW, what did say the captain ? Nothing ... ?

BEA, just publish the data, and if we don't deserve them, the victim's families surely do. Why can't they get them ... ?

Graybeard

How come BEA didn't know the takeoff cg was 23% at time of first report? Why didn't they do your math?

As long as BEA is being vague and inspiring wild guesses: what is the chance that the takeoff cg was really 30%, and not 23%? You can see where that would lead..

Is cg calculated based only on pre-takeoff W&B, or is it computed constantly from AOA, IAS, ALT and trim?

grity

for me cg seems calculated based only on pre-takeoff W&B.... and fuel consumption....

who made the load- and fuel-weight datainput normaly?
there can also be a data entery error, captain again needs best skills to control this



@ john tullamarine can you explain the different places of the pitots between A+B, can this have an influence of the reliability (ice)

A33Zab

Happen to have deactivated a THS tank a few months ago, due to access panel leakage.
Repair interval Cat C (10 days), empty TT; manual closing and deactivating TT isolation & TT inlet valve to prevent fuel entering TT but to keep trim pipe with fuel for APU ops.
Crew selects TT Tank Feed switch to ISOL, 1% fuel to be increased due CG control not available.
Indeed very rare, it was the first time in our company.

@GB:

Flight preparation:

The flight crew should insert the weights after completing all other insertions. This is to avoid cycles
of prediction computations at each change in flight plan, constraints, etc...
If ZFCG and ZFW are not available, it is acceptable to enter the expected values in order to obtain
predictions. Similarly, the flight crew may enter the expected fuel on board, if refueling has not been completed at that time.
If ZFCG, ZFW, and BLOCK FUEL are inserted, the FM will provide all predictions, as well as the EXTRA fuel, if any.

In Flight: