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Lufthansa Hamburg

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Lufthansa Hamburg

Old 16th May 2008, 09:24
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according to the preliminary status report from BFU
http://www.bfu-web.de/nn_41542/DE/Pu...tin2008-03.pdf
... surely is to be found in the BFU report when it sees the light of a day. I hope to see answers whether:
LH publishes operational and final x-wind limits to crew
Yes they do, kind of, call it "recommended". See page 27 of the report. 30 kt for uncontaminated runway.
the actual wind was beyond demonstrated Airbus value
See page 25. actual 2 min average was 33 kt from 300
Tower gave last wind information with landing clearance app. 90 seconds before the incident as 29 kt from 290 with gusts 47 kt
an alternate runway was available
Yes. Tower offered RWY 33 alternatively. Captain decided to attempt 23 first.
the scrape occured with dual input
Yes. See page 26 for the graphs of the FDR recording. While 15 ft above ground PF commanded left roll, PNF commanded right roll (PNF stick 4.5 degree right deflection). Then PF also input right roll and 28 deg left rudder.
FBW followed rudder input only shortly, and after initial max deflection executed a smoother rudder deflection than was commanded by PF, that moment the gust hit...
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Old 16th May 2008, 10:41
  #42 (permalink)  

Only half a speed-brake
 
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Thanks Interflug for picking those out. As expected. All that remains now for me is to answer am I any better pilot-operator than the LH capt? Presumably not by a wide margin. What will stop me from repeating their mistakes one day? That is not an easy one.

Originally Posted by Interflug
Yes they do, kind of, call it "recommended". See page 27 of the report. 30 kt for uncontaminated runway.
That's intresting. My OM-B uses AB demostrated values (33g38) but they are prescribed as absolute limits, i.e. starting the approach with G47 is clearly illegal for me. I wonder how other company policies handle this.

FD (the un-real)
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Old 16th May 2008, 11:27
  #43 (permalink)  
 
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Limits

ILS 23 - 90 seconds before the incident as 29 kt from 290 with gusts 47 kt
For the steady crosswind that is only a 25,11kt crosswindfactor.

That is a max gust factor of only 40.7kt at RWY 23, but with an ILS

Granted AB OM-B says demostrated values (33g38), because they did not fly with higher winds while testing.

I think it is better to stick with the rules of: consider gusts if operational significant or something like that as printed somehow like this in the LH manuals as I got told.

This gives the judgement to the Commander.

Approaching HAM via RWY 33 and the buildings close by and only a non precision approach is definetely the second choice for me. There must have been good turbulences in the T/D sector on 33 that day.

For me decision was o.k. and would have started the approach as well. But definetely not on 33.


By the way FlightDetent, check your AB manual about landing technique and you will see, that the manual is very brief about it and never mentions to drop the wing a little bit and touch with the upwind LG first. But you got to do this in heavy winds and will not be able to land without doing it.

But this a liability reason and not so published in the manuals from AB but from the airbus pilots it is trained to the customers. ;-)
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Old 16th May 2008, 12:11
  #44 (permalink)  

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True that I have incorrectly treated the 29G47 as a crosswind, comparing it to 33g38 demonstrated (AB AFM) or limiting (company OM-B) values. Most incorrect and thanks for pointing that out.

Once the direction enters the equation, crosswind
R33 is 17g30;
R23 is 25g40.

and there goes my sorry a$$.

A320 FCTM
CROSSWIND CONDITIONS
On initiation of the flare, rudder should be applied as required to align the aircraft with the runway centreline. Any tendency to roll downwind should be counteracted by an appropriate input on the sidestick. It is possible that a very slight wing down may be required to maintain the aircraft on the runway centreline.
In the case of a very strong cross wind, a full de-crab in the flare may lead to a significant bank correction which may reach the aircraft lateral geometry limit. Consequently, combination of the partial de-crab and wing down techniques may be required.
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Old 16th May 2008, 12:36
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ILS 23 - 90 seconds before the incident as 29 kt from 290 with gusts 47 kt
For the steady crosswind that is only a 25,11kt crosswindfactor.

That is a max gust factor of only 40.7kt at RWY 23, but with an ILS

Granted AB OM-B says demostrated values (33g38), because they did not fly with higher winds while testing.

I think it is better to stick with the rules of: consider gusts if operational significant or something like that as printed somehow like this in the LH manuals as I got told.
But what if the crosswind is anything than "steady"? 29 kt was an arithmetical average over 2 min, the actual speeds fluctuating between 18 - 47 kt changing directions between 268 and 323.
Statistically you have a 50% chance of encountering higher crosswind than average any moment up to 47 kt. (Assuming following gusts would stick to the maximum set by their predecessors :-) The METAR predicted G55 btw.

Also the LH manual recommends 30 kt max. crosswind for an uncontaminated runway. Actually the runway was wet, which according to LH OM would reduce the max. crosswind to 25 kt or even less, depending on reported braking action.

Would you still decide to land?
If yes, would you let the F/O (327 hours on type and 579 hours total) land in these conditions and try to establish a higher max. demonstrated crosswind gust with passengers than Airbus' own test pilots without passengers? (captain 4123 on type and 10203 total according to BFU report)

I'm just asking.

Last edited by Interflug; 16th May 2008 at 12:57.
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Old 16th May 2008, 13:13
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I think the PIC's Captaincy should be called into question here. The F/O should not have been asked to do the landing in those conditions and anyone that tells me the PIC should have let the poor F/O fly, so the Captain could "watch" the proceedings I say BS!!! If you as Captain decide to try and land in those conditions, then you fly the thing. Lead by example!

I know Captains in the past that would blame the F/O if there was a screw up. If the cap fits wear it! Responsibility (and authority) ,cannot be delegated.

Maybe I am getting too old, as a lot of the modern "thinking" I find stange at times.
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Old 16th May 2008, 16:43
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I find it hard to understand the Capts decision making for that approach. To try and land in crosswinds above the demonstrated figures is one thing, but to let a very inexperienced f/o carry out the landing attempt is unbelievable. He may have believed his own ability was sufficient, however the fact he did not take over complete control in the recovery does not reflect his perception.
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Old 16th May 2008, 17:10
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BigShip: I've never landed in Hamburg, so I can not comment on your local knowledge of rough air over obstacles near to either threshold. However, is it not the case that gusts often cause the wind to veer. Thus, if this were so on this day, would a gust not have reduced the X wind component for RWY 33 and increased it for RWY 23?
I can't remember from earlier in the thread the exact weather conditions, but from the photos they were visual well out from the rwy. Does it therefore matter if the approach was an ILS or NPA? Either would have offered plenty of time to complete the landing visually.

There is also a thought, among medical thinkers, and perhaps pilots, that it is more natural to have the drift coming from the opposite side to your seat. Thus you apply rudder to correct the drift towards your side. Perhaps it is because you have much better visibility through your fwd window (perhaps even the side one?) during short finals and the final flare. In this case the F/O would have been better on RWY 33 and the captain on RWY 23.
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Old 16th May 2008, 20:25
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Why do some pilots think that they can land at or even above a demonstrated crosswind value? This is not to judge the incident crew; they might have misheard the wind speed, or made an error in calculating the component.
It appears to me that there is an underlying belief that a ‘demonstrated’ value need not be given the same respect as a limit. Some aircraft limits can be inadvertently exceeded without undue risk because they have a margin for error or environmental variability, but a demonstrated value may have no such margin.

Usually demonstrated values are determined with accurate wind measurement and on dry runways. The value is a judgement call by the test / certification team, but who is to say that ‘the limit’ is not just above the demonstrated value. Also, the flight test judgement assumes a ‘standard’ pilot, but there are no definitions of experience, currency, standard of training, capability, etc, and there are no allowances for human factors.
It would seem very sensible to provide a margin from any demonstrated value when publishing an operational limit to cover eventualities above and ‘the Commander’s judgement’. This is not to remove operational judgement, but to guide it, and ensure that the operation is not at the limit of safety; it would provide a ‘buffer’ for the unknowns such as wind-speed calibration, gust variability, and local terrain effects.
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Old 17th May 2008, 08:53
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page 27 of the BFU report makes very interesting reading. From the LH QRH I assume.


Maximum crosswind dry or wet 30Kts - no mention of whether gusts are included or not, in what I guess is the 'company limits'.


Then it gives a 'Note' stating the demonstrated crosswind components from the manufacturer. If you don't want to have the crews operate in crosswinds greater than 30 knots , why add a note offering a higher figure at all? Interestingly the 'company limit' for take off is 30 kts the manufacturer demonstrated value is 29 kts. Did LH do some further trials before increasing the limit or have I miss-read this?


Then in the table for contaminated runways in the row for 'good' braking action greater or equal to 0.40 they give a 25 kts limit. Obviously we wouldn't look at this table in the with regard to the Hamburg incident; except look it has an equivalent runway condition condition of dry - what is this doing in a table for contaminated runways?


So the QRH seems to contain three possible sets of values to choose from - could this not confuse the crew.
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Old 17th May 2008, 13:20
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Then in the table for contaminated runways in the row for 'good' braking action greater or equal to 0.40 they give a 25 kts limit. Obviously we wouldn't look at this table in the with regard to the Hamburg incident; except look it has an equivalent runway condition condition of dry - what is this doing in a table for contaminated runways?


So the QRH seems to contain three possible sets of values to choose from - could this not confuse the crew.
We still need the manual how to read the manual

I would interpret this as max. 30 kt when runway is not contaminated and max. 25 kt if runway is wet but no limited breaking action has been reported.
Since EDDH RWY 23 was pretty wet at the time of the incident as everyone can clearly see from the video, 25 kt should be the company limit according to LH OM.

But however, the problem was the gust, not the "average" crosswind.
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Old 17th May 2008, 16:25
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My humble pinch of salt:
What you guys are debating here, are maximum demonstrated crosswind limits that have been flown by test pilots, as seen here http://www.youtube.com/watch?v=ljOxo0s33sI and here http://www.youtube.com/watch?v=GHrLB_mlir4 etc
As may be observed, those tests all take place in obstacle devoid areas and in obviously strong, but steady crosswind conditions.

The LH approach into Hamburg:
- was done on runway 23 in gusty crosswinds
- encountered a large gust (mostly due to the gap in the tree line on the RW33/23 intersection) that destabilized the craft
- was probably not corrected in a timely (well, no wonder, sidestick inputs having first to be analyzed by a row of computers before eventually allowing a flight control deflection...) and correct manner
- could most probably have been recovered in a conventional craft. The wonder Bus scores in a lot of areas, but certainly not in gusts
- was flown by a pretty inexperienced F/O
- certainly (once more) demonstrated the limits inherent to the non-linked sidesticks


live 2 fly 2 live

PS
Danke LH Kollege, habe dank euch wieder ein Paar Sachen gelernt
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Old 17th May 2008, 16:43
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my 2 cents

could most probably have been recovered in a conventional craft. The wonder Bus scores in a lot of areas, but certainly not in gusts
I guess it depends on who is driving, with over ten years on the bus I can assure you it handles all wind conditions very well, no complaints.
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Old 17th May 2008, 16:46
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Lack of experience seems the main explanation in this accident.

Further in the German report we read that the co-pilot had only 579 hours, of which 327 on type... Line training was not far behind.

The captain's decision to let her land in this wind conditions is highly questionable. If I were on that plane as passenger and knew that an inexperienced F/O were going to land the plane, I would definitely be pissed.

After all it's the JAA's fault.
Unlike the FAA, they do not encourage experience building and lowering of cost of training, making hiring standards at airlines very low.
Minimum required flight time before hire in the U.S.? 500-600 hours.
In Europe? 200 hours.

It's an accident waiting to happen.
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Old 17th May 2008, 17:00
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Boeing x Bus

Having flown Boeings for 24 years, with a little more than an year interruption on A320, I can state that, while the Bus wins hands down on a lot of fields over the 737 (cockpit ergonomy, roominess, "user friedliness" etc), on gusty winds the situation is completely different: it's well known the A320/19 tricky behavior, to say the least.
No question that under that conditions 737 would be much more manageable.
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Old 17th May 2008, 17:02
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As previously stated...
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Old 17th May 2008, 23:24
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F4F:
(well, no wonder, sidestick inputs having first to be analyzed by a row of computers before eventually allowing a flight control deflection...)
It's an incredibly optimised datapath - we're talking less than a millisecond for that computation.

certainly (once more) demonstrated the limits inherent to the non-linked sidesticks
And if the CP couldn't correct it in time because of the force-feedback? Could have been much nastier.
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Old 18th May 2008, 06:43
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SLF here. Could lack of feed back between side sticks have a role in this incident as well?
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Old 18th May 2008, 09:22
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SLF here. Could lack of feed back between side sticks have a role in this incident as well?
What I've missed on the 320 was the feedback of airload on the stick. With a conventional control wheel you can feel the gusts. Pressing a bungee, you don't.
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Old 18th May 2008, 10:07
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taken from another forum:

I bet that below 50 feet neither pilot no longer knew where the inputs came from. Gust or computer? Copilot or skipper?
A lot of truth in this!
Much less prone to happen with a interconnected yoke.
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