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-   -   737 Crosswind crabbed Landing stuffed up. (https://www.pprune.org/tech-log/637022-737-crosswind-crabbed-landing-stuffed-up.html)

Centaurus 25th Nov 2020 11:50

737 Crosswind crabbed Landing stuffed up.
 
https://www.flightglobal.com/safety/...141233.article

Full description: https://www.businessinsider.com.au/t...9-11?r=US&IR=T


DaveReidUK 25th Nov 2020 13:04

The aircraft in question was written off as a result of the accident.

Uplinker 29th Nov 2020 09:28

This sort of thing annoys me. All pilots certainly need to be able to land in a crosswind.

Yet this captain did not know what to do? And not so long ago we had the captain of a cargo turbo-prop landing at Birmingham who also did not know what to do with a crosswind in the flare and went off the runway.

Unbelievable. I hope for this crew's sake, they had a jammed rudder in the flare and it was not due to their incompetence.

Having said that, how many pilots are actually tested on their crosswind flare technique before being offered employment?


vilas 29th Nov 2020 15:21

There is no difference in flare technique in crosswind. What is different is on dry runway after flare you remove the crab. In strong crosswind Airbus allows to land with 5° crab and/or bank. It's not Landing with crab alone has caused this but inefficient rudder handling after touchdown and use of nose wheel steering at high speed has caused the damage.

safetypee 29th Nov 2020 15:58

Crosswind landings; if operators place limits on first officers, then with Captaincy how might they judge personal capability in limiting conditions, which they have never experienced before.
Not with simulation, unrepresentative simulation of conditions and little or no lateral acceleration to help judgement of drift correction.
Both management and individual false belief in capability; press on, peer pressure, poorly measured and reported conditions.

Need to add some personal margin. Risk is the amount of uncertainty which has to be managed.

Judd 1st Dec 2020 13:17


Not with simulation, unrepresentative simulation of conditions
Providing the Level D simulator is well maintained, the fidelity of crosswind landings in terms of basic handling of flight controls is almost identical to the real aircraft. I am talking here about the 737 Classics. Most syllabus I have seen do not permit enough time to practice crosswind landings. For type rating purposes the "student" may need to practice at least ten crosswind landings one after another to be able to land with reasonable self confidence and consistency of no drift touch down. There is nothing wrong with repositioning the simulator at one mile final which with any Level D simulator will have the correct drift angle and speed and power setting automatically in place. This presupposes of course the aim of the exercise is to finesse the flare and landing manually with a 90 degree crosswind component of varying speed.
Some pilots are slow to recognize or "see" drift angle. They under estimate the drift angle on touch down and hit the runway still sideways.

When this happens a good instructor technique IMHO is to "freeze" the simulator at the instant of touchdown. Then have the student look at his compass heading compared with runway heading when it will be obvious there is a difference. Cross wind landing practice in the simulator is frequently glossed over because of time constraints and is rarely conducted over 20 knots crosswind component. This is not because of perceived simulator fidelity but instructor apathy. Equally it is extremely rare for an instructor to take a control seat to demonstrate a strong crosswind landing for fear of making a twit of himself in front of his student. In Asia it is called Loss of Face.. :{

Stuka Child 1st Dec 2020 16:10


Originally Posted by vilas (Post 10936904)
There is no difference in flare technique in crosswind. What is different is on dry runway after flare you remove the crab. In strong crosswind Airbus allows to land with 5° crab and/or bank. It's not Landing with crab alone has caused this but inefficient rudder handling after touchdown and use of nose wheel steering at high speed has caused the damage.

I would hope that on *any* runway one would remove the crab after main gear touchdown. Also, as far as I remember, you're not supposed to land with crab on a dry runway in a 737.

vilas 2nd Dec 2020 08:49


Originally Posted by Stuka Child (Post 10938271)
I would hope that on *any* runway one would remove the crab after main gear touchdown. Also, as far as I remember, you're not supposed to land with crab on a dry runway in a 737.

Crab needs to be removed before main gear touchdown and not after. Touching with crab on a dry runway imposes severe side stress.The gear can take impact loads but is not designed for side stress. On a wet or slippery runway if you touchdown with the crab the aircraft skids straight on which reduces the sideway stress and then due to CG position straightens automatically. On wet runway Landing with crab prevents premature removal of crab with downwind draft which will result in a GA.

Uplinker 2nd Dec 2020 10:28

Yes, absolutely, you should remove any crab before the mains touch; just think of the forces on the main gear otherwise - be a pilot, don't be lazy !
My technique is to flare and de-crab as one smooth coordinated movement, so crosswind flares are different to head/tail wind flares.

Myself and my then pilot colleagues came up the long way from flight school - via small turbo-prop twins, larger turbo prop twins, even larger turbo prop twins, medium sized four engined jets, then onto medium and large twin jets after about 3 years experience. So we had lots of landing practise on the line in all weathers, in aircraft with very little inertia and stability, so we perfected our crosswind technique before moving onto the big jets. Coming out of flight school straight onto a medium twin jet must be quite tricky in terms of manual handling !!

In my experience, SIMs are often wasted because we spend a lot of time in them flying around the hold working through long tech problems or doing Loft exercises. That sort of procedural practise could be done in a much cheaper fixed base SIM. The full SIMs should be taken advantage of for manual handling practise. No SIM can perfectly reproduce all the physical forces - because obviously they can't physically move very far - but a crosswind approach and pushing straight in the flare could be practised - leading straight into a go-around perhaps rather than touching down.

Brookmans Park 2nd Dec 2020 11:30

The 737 u/c has a small amount of caster (5°?) which permits a slight crab at touchdown

Stuka Child 2nd Dec 2020 16:45


Originally Posted by vilas (Post 10938727)
Crab needs to be removed before main gear touchdown and not after. Touching with crab on a dry runway imposes severe side stress.The gear can take impact loads but is not designed for side stress. On a wet or slippery runway if you touchdown with the crab the aircraft skids straight on which reduces the sideway stress and then due to CG position straightens automatically. On wet runway Landing with crab prevents premature removal of crab with downwind draft which will result in a GA.

Lol we are saying the same thing.

RVF750 3rd Dec 2020 14:14

Lot of non 737 pilots posting here. As BPK says the main gear has a system where the gear oleo can rotate against a samper, with several degrees of movement. It's normal to both take off and land in crosswinds with the aircraft turned into wind up to 5' with a little tyre scrub as well.
One notable issue with the -800 I find is to completely line up the aircraft in the flare is not a problem, the rudder is very effective. What is the problem is the roll authority is not enough! You can keep the wings level up to about 20kts of cross wind component, above that you hit the stops and must accept a little crab or it wil lroll out of wind wing low- something you do NOT want!

All aircraft respond differently in de-crab, its an acquired skill, you simply cannot teach by rote. You have to practice, again and again. After 12,000 hrs in a variety of aircraft, I still don't get it right all the time. Anyone who says they do is lying. Too many variables!

If you land with a little crab, the autobrakes help it swing straight, and applying rudder will give the nosewheel the steering angle as it comes out of full extension too. Some days it all comes together like a magic thing...others its a bag of worms. That's life on the line!

Uplinker 4th Dec 2020 11:19

(I have flown A320 family and B737, but not the -800).

How does the cadet, going from flight school into a big modern jet cockpit learn crosswind technique? = by practising. On a crosswind or turbulent approach take the A/P out at 10 miles rather than at 1 mile so you can get into the groove of the conditions, and experience flying crabbed, so by the time you get to DA, you are well up to speed and in control. Then flare while pushing straight with the rudder.

This could be practised in the SIM, but in my experience it never is.

vilas 4th Dec 2020 13:48


This could be practised in the SIM, but in my experience it never is.
It is and it should be as a rule. Sim time should be utilised to practice something challenging.

OhNoCB 4th Dec 2020 14:24

I think things like this might get worse with newer pilots/captains before they get better. Each but one company I have worked for has imposed crosswind limits on first officers. One company lifted the restriction upon becoming SFO whilst the other retained it indefinitely.

Two problems from here then. The second company that retained it indefinitely meant that the first time that pilots skill was ever called upon was when they were brand new in the left seat. Not good. The other company that lifted the restriction for SFO's.... well that is good in theory, except that it was heavily suggested to the skippers that they should be very careful about who is doing what, and was it sensible to have the 1500 hour pilot landing in max xwind when there was a 15000 hour pilot beside them? From a pilot development point of view it's great, from a liability point of view it is not so great.

The company I am currently in does throw these into the sim from time to time, with the focus aimed at development/training for FO's, but I personally think even in a level D sim, it doesnt give the best representation of reality.


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