B737 x-wind take-off

[framer]

After reading the Denver thread I did a search for more xwind takeoff info on the 737. The other threads are closed so I thought it couldn't hurt to start another. This is a quote from another thread;

Firstly, about 10 degrees of control wheel movement is required to cause spoiler deployment. This is a very small control wheel input, yet I found this was ample to maintain directional control with a 34 knot crosswind (maximum for my model B737).

There was only 2 degrees of bank on the takeoff roll, yet almost full control wheel input (and full spoiler deflection) was required to level the wings. My opinion is that large doses of aileron/spoiler are not required to maintain directional control.



When I did my type rating we were taught that only 10 degrees control wheel input into wind should be used for a max xwind take-off to prevent spoiler deflection. The rest of the directional control needed, should be achieved by rudder. They also said that the control wheel input will need to be increased through the rotation to keep the wings level and that a rough guide to how much deflection is approx twice the xwind. For example if there is a 20kt xwind, then during the rotation the control wheel will need to be progressively moved through to about 40 degrees deflection.
I have found that this works quite well in real life.
In observing others take off in xwinds I sometimes think that they use too much of the ten degrees allowable aileron and as a result end up with very large rudder inputs to keep tracking straight down the strip. I don't consider myself an expert in this area by any means and would appreciate others opinions (if you are 737 rated).
Cheers, Framer.

[AirRabbit]

When I did my type rating we were taught that only 10 degrees control wheel input into wind should be used for a max xwind take-off to prevent spoiler deflection. The rest of the directional control needed, should be achieved by rudder. They also said that the control wheel input will need to be increased through the rotation to keep the wings level and that a rough guide to how much deflection is approx twice the xwind. For example if there is a 20kt xwind, then during the rotation the control wheel will need to be progressively moved through to about 40 degrees deflection.
I have found that this works quite well in real life.
As a former B-737 guy, the only thing I would have added is that as the rotation continues, the aileron input is adjusted to maintain wings level and as the nose gear leaves the runway surface, adjust rudder input to keep the ball centered. Otherwise, I quite agree with all of the above – particularly, the last sentence!

[framer]

Is it possible to see on the hydraulic pressure gauge the needle quiver when the spoiler rises? I just had a thought then that this may be the case and prior to lining up I could look at that to get a feel for where the max deflection is.

[TopSwiss 737]

In a previous life flying the 737, a tailstrike happened in the company during crosswind conditions.

One of the findings in the investigation was that, due to excessive control wheel displacement (obviously to counteract the effects of x-wind) spoiler deployment occured. This, in addition to the use of flaps 1 which of course also reduces tail clearance, probably was an attributary factor in the scraping the back end (i.e. loss of lift and thus delaying lift off)...

Just my 2 cents worth. TS737

[framer]

Rainbow, I respect your opinion and most certainly your experience butI have never heard any of my training captains or line captains say that the spoiler activation doesn't matter.
Page 3.13 of the FCTM says "Use of excessive control wheel may cause spoilers to rise which has the effect of reducing tail clearance"

I wonder if having more aileron in than is required for the conditions results in more weight on the upwind wheels, which in turn causes a slight pull in that direction, which results in more rudder being required to track the centerline. Does that sound feasible?

[fireflybob]

There seem to be so many different opinions as to how much aileron to apply during a crosswind take off on the B737! I go for more rather than less so tend to agree with Rainboe.

But when it comes to a potential tailstrike no mention ever seems to be made of rotation rate. I believe that Boeing recommend 2 to 3 degrees per second. If we take the average of 2.5 degrees per second this means it should take 6 seconds to reach 15 degrees. Quite often I see quite rates of rotation which appear to exceed the Boeing recommendation by a fair amount.

One tip I got was the 10/10 rule - don't exceed 10 degrees pitch up below 10 ft radio height - easy to remember and might keep you out of trouble.

Fly Safe in 2009!

[Centaurus]

Spoiler drag on roll is negligible. The darn things don't have much effect below 250kts even, below 140 kts hardly any effect at all

Friend of mine was F/O during a take off in a 737-400 with 25 knot crosswind from the right. The captain pre-set almost full wheel travel right from brakes release. This was his personal choice not a company requirement. The aircraft was runway length limited on this take off. As the story was told to me by the F/O a few days later, around 120 knots the acceleration slowed markedly and at VR the aircraft was extremely close to the threshold.

He described the decelleration as like a car going through a deep puddle and momentarily slowing except this was a 737 that kept going and the V1 was clearly invalid under these circumstances. During simulator training we demonstrate the effects of spoiler extension without reverse actuation or RTO braking during a high speed rejected take off. In the simulator at least there is a definate sense of immediate decelleration and after initial engine spool down the decelleration green arrow is seen on the PFD. As the speed slows below 80-90 knots the green arrow shortens. This suggests that the spoilers when extended at high speed during take off do definately add significant drag for a short period.

This further suggests that excessive control wheel deflection to counter a crosswind in the 737 during the take off run could invalidate V1.

[DC-ATE]

OK.....let's throw some more wood on the fire.

The way I'VE always done it from day one in a Piper Super Cruiser through many other bug smashers, light to medium twins, Connies, DC-6/7, B-737 (200 & 300), and DC-8s is: Up to max aileron, depending on the amount of x-wind during the initial phase of the take-off roll. As speed increases and the aircraft becomes more "flyable", start relaxing the amount of input. Natural. Of course all this time you're using rudder as well. It IS a coordinated maneauver. The aircraft should lift off tracking right down the centerline, but significantly crabbed into the wind depending on the amount of x-wind, naturally. Don't worry about the darned spoilers. As you start to relax on the wheel with speed increasing, the spoiler deflection will be decreasing.

Simple maneauver.

Next.....

[rubik101]

Those of you reading this who might be fairly new to flying might believe that all that is written by those of us with 'over 20.000 hours' might contain 'good' information. Sadly, this is not the case in this instance, as is so often the case amongst certain posters!.

All the information relating to crosswind take offs from Boeing is contained in this memo.

Read and learn how it should be done!

Memo. Cross-wind Take-off Techniques.

In cross wind conditions it is not uncommon to see large control wheel displacements (and excessive forward pressure) during the takeoff roll in an attempt to improve directional control.

This is not the correct handling technique and greatly increases the
possibility of a tailstrike. The FCTM (3.14 and 3.15) is very clear in this area. The greatest threat to a take-off in strong and gusty crosswind conditions is in fact tailstrike and not directional control.

Guidance material on the prevention of tailstrikes is provided in a number of our approved manuals which are summarised below:

Boeing FCTM: Directional Control
“....Smooth rudder control inputs combined with small control wheel inputs result in a normal takeoff with no overcontrolling. Large control wheel inputs can have an adverse effect on directional control near V1(MCG) due to the additional drag of the extended spoilers.”

Limit of control deflection without spoiler activation 1.5 units

Boeing FCTM: Rotation and Takeoff

“Begin the takeoff roll with the control wheel approximately centered. Throughout the takeoff roll, gradually increase control wheel displacement into the wind only enough to maintain approximately wings level.

Note: Excessive control wheel displacement during rotation and lift-off increases spoiler deployment. As spoiler deployment increases, drag increases and lift is reduced which results in reduced tail clearance, a longer takeoff roll, and slower airplane acceleration.

At lift off, the airplane is in a sideslip with crossed controls. A slow, smooth recovery from this sideslip is accomplished by slowly neutralising the control wheel and rudder pedals after takeoff”

Boeing FCTM: Gusty Wind and Strong Crosswind Conditions.

ALL of this section of the FCTM is crucial to understanding how to avoid a Tailstrike in these conditions but the following is particularly relevant to this memo: -

To increase tail clearance during strong crosswind conditions, consider using a higher VR if takeoff performance permits. Avoid rotation during a gust. If a gust is experienced near VR, as indicated by stagnant airspeed or rapid airspeed acceleration, momentarily delay rotation.

“......Do not rotate early or use a higher than normal rotation rate in an attempt to clear the ground and reduce the gust effect because this reduces tail clearance margins. Limit control wheel input to that required to keep the wings level.
Use of excessive control wheel increases spoiler deployment which has the effect of reducing tail clearance. All of
these factors provide maximum energy to accelerate through gusts while maintaining tail clearance margins at lift-off.”

Boeing FCOM Volume 2
Page 9.20.5, Flight Spoilers, states: -

“The flight spoilers rise on the wing with up aileron and remain faired on the wing with down aileron. When the control wheel is displaced more than approximately 10 degrees, spoiler deflection is initiated.”
10 degrees approximates 1.5 units of Aileron Trim.
Operations Manual Part A
Existing procedures designed to reduce the risk of Tailstrike are: -
Ops A 8.0.10 Co-pilot Flying
When flying with inexperienced co-pilots or a co-pilot newly converted onto type, the Commander shall perform the take-off or landing himself when the following conditions are experienced:
1. Crosswinds more than 2/3rds of limiting value.
Ops A 8.3.0.1.5 – Take - Off Flaps
Flap 5 is the normal departure flap setting; flaps other than Flap 5 shall be used when operationally necessary. If crosswind component is in excess of 10kt fixed derate is permitted, however assumed temperature thrust reduction is not permitted.
All Flap 1 departures shall be flown by the Captain as PF.
Boeing FCTM: Gusty Wind and Strong Crosswind Conditions
The FCTM Gusty Wind and Strong Crosswind Conditions section gives guidance as to how to comply with Boeing’s recommendation that rotation be delayed in these conditions. Specifically: -
“To increase tail clearance during strong crosswind conditions, consider using a higher VR if takeoff performance permits. This can be done by:
• Increase VR speed to the performance limited gross weight rotation speed. Do not exceed VR gross weight + 20kts.
• Set V speeds for the actual gross weight. Rotate at the adjusted (higher) rotation speed. This increased rotation speed results in an increased stall margin, and meets takeoff performance”
In practice, this means that there is no change to procedure and PM will call VR at the set speed but PF may delay rotation to the gross weight VR.

Summary

• Smooth rudder control inputs combined with small control wheel inputs result in a normal takeoff with no overcontrolling.
• Any control-wheel deflection more than 10 degrees (approximately 1.5 units of Aileron Trim) will activate the spoilers.
• Spoiler activation reduces aircraft energy which requires a higher attitude to generate the lift required for takeoff. This increases the risk of a Tailstrike.
• Do not rotate early or use a higher than normal rotation rate because this reducestail clearance margin.

[Meikleour]

Rainboe,

Just an aside to your comments regarding the minimal effects of spoilers at low speeds, I remember from my B707 days that there was a performance weight penalty to be applied when taking off in crosswinds that exceeded 15kts component to allow for the spolier drag although I can`t remember (senior moment here) if there was an aileron `dead band` or not but the handling advice was "aileron angle on the yoke equal to the crosswind component". B737 and B747 both had similar advice. It is only the AIRBUS that mention restricting the aileron to a value below spolier deployment value.

PS in 41 years flying - 6 years on the VC9. Now that really was a horribly handling aeroplane!

[DC-ATE]

Rainboe -

"The way I see it, ANY aileron has no effect up to about 80 kts in a big jet, so why not just hold the estimated amount on steady from the start, and leave it there and not worry about it again?"

You'll note that I said UP TO max deflection depending on x-wind. Kinda the same as your "estimated" the way I see it.

[Rhodes13]

Rubik 101 Hear hear. Why do people try and reinvent the wheel?

The manuals are the authoritative source of information on how to fly your aircraft. If a problem arises and you have deviated from the manuals because of wives tales and "this is the way I have always done it" your tail is on the line! Not only from the company but god forbid if you were ever then in court trying to defend yourself.

I am not a test pilot and I hope never to be, thats why boeing airbus etc employ people to do these things, Im sure they have tried everything and found the best way to handle the aircraft.

[TopSwiss 737]

Post #5
A search would have brought up a cascade of information here about all this. But can you say how much drag you think a cracked spoiler gives you up to 140kts when you get airborne? Do you think 10 degrees of aileron is really enought to prevent wing lift at higher take-off roll speeds?


I dunno Rainboe, I am not a performance engineer. :8
Was just trying to put some info from an extensive incident report into this thread...

Boeing procedures seem to support this I guess...

[DC-ATE]

Well, there's the right way, the wrong way, the company way, the manufacturer's way, the test pilot's way, and the Captain's way. The Captain is always right, right?!

Anyway, between myself, Rainboe, and numerous other Captains on here, we probably have over a million hours of experience compared to a few hundred hours that "test pilots" have.

Boeing said the tail of their 737s could not ice. That was an outright dumb lie.

[Rhodes13]

So we should just disregard what is written in the manuals and thus becomes a legally binding way to operate the aircraft because you are the oracle?

Tell me which airline you fly for where blatant disregard of the FCTM, Flight manual and SOPS is allowed!

You must be a joy to work with in the cockpit with that god like complex you have. I pity the Fo's that fly for you, they must be constantly in awe as you teach them everything and show them that boeing are wrong! :ugh:

PS I'm sure the test pilots have more time in interesting situations with the aircraft on the limits of the envelope than the millions of hours that the likes of you and Rainboe etc have. I would trust their judgement a hell of a lot more than your "wives tales."

PPS No the Captain isn't always right.

[Centreline747]

In the dim and distant past, I recall an incident where a well known carrier had a 747 classic depart from NRT to LGW, fully laden, and had a hydraulic fault that caused some of the spoilers deployed during TO. This wasn't picked up on the SPI but was noticed by the crew once airborne due to the 'vibration' and sluggish climb. The fault was rectified by isolating the hydraulics to the associated spoilers on the overhead panel, you know the guarded switches we never touch! and the flight continued to destination without further ado. Says a lot for Boeing - it will fly!!
My point is, will a small amount of spoiler deflection really make much of a difference? Just my opinion!:)

[Centreline747]

PS Anyone been to 'The Truck' recently, how I miss that place (NOT!!)

[DC-ATE]

Rhodes13 -
"So we should just disregard what is written in the manuals and thus becomes a legally binding way to operate the aircraft because you are the oracle?

Tell me which airline you fly for where blatant disregard of the FCTM, Flight manual and SOPS is allowed!"



Come now.....you can certainly read between the lines. It was a take off on "the right way, the wrong way, and the Army way". However, there IS some truth in there if you've spent enough time in airplanes, as many of us have, and seen some of the things that "can't go wrong" that DO go against what you've read or heard. Only experience tells you what can and does happen out in the real world.

BTW.....I'm retired from the Friendly Skies.

[olster]

This thread highlights the perils of pprune.I rarely post here for the ritual flaming that accompanies attempting to bring the real world to the party versus 'top tips'and 'pet theories' which abound around here.I am a 737 TRE with a uk leisure airline and previously with the orange brigade.My advice,for what it's worth is that you must follow the FCTM guidelines in conjunction with your company sop's.I will not reiterate that advice-please go read it- but suffice to say that crosswind take off technique is precisely and accurately prescribed and has been contradicted in these posts.Boeing test pilots do know what they are doing and ignoring FCTM guidance to follow pet theories (published on pprune)is perilous and inadvisable.

Happy landings in 2009.

[repariit]

"Anyway, between myself, Rainboe, and numerous other Captains on here, we probably have over a million hours of experience compared to a few hundred hours that "test pilots" have."


This may have been a tounge-in-cheek comment, but there have been incidents where airline pilots have done experimental flying with a full load of passengers with bad results. When you deviate from the Flight Manual you are a test pilot without a test plan.

It may not be widely known, but the first 737-100 in the Boeing test program was fitted with bail-out provisions. The Fwd baggage door was hinged on the leading edge and had a hydraulic actuator that could push it open against the airstream. A section of floor panel was removed above it and a grab handle was installed above the hole so that crew members could hang from the handle so that gravity would align them with the open floor and cargo door, g forces permitting. It was never used, but there were a couple of anomalies.

The 737 leading edge devices did not have locks on them initialy because wind tunnel data showed that aero forces would keep them tight against the wing in flight. Boeing has thousands of engineers with every applicable specialty that test and analyze every possibility prior to test flights. During one of the high speed tests the leading edge devices popped out and were badly damaged. The crew regained control despite the resulting asymetric leading edge, and managed a flaps up landing at BFI.

Another anomally was that the original TR's actually caused the 737 to speed up when they were applied. Both TR doors deflected thrust under the wing which created lift that reduced braking effectiveness greater than the reverse thrust forces. The fix was to clock them so that one TR door deflects thrust above the wing.

One in service "test flight" that went badly was a 727 flown about 35 years ago by a fellow named Hoot Gibson. Hoot decided that he could deploy a litte flaps at cruise to achieve a higher altitude. The 27's did have locks on the leading edge devices, but guess what? Hoot just unlocked them! The result was much the same as the 37 real test flight. Hoot took a 30,000 foot spiral dive. Initial press reports extolled his hero flying skills, but when the facts were known he was unemployed.

There is good reson to do it by the book.

[Rhodes13]

Or perhaps Rainboe you should read and follow the FCTM?

Raiboe I'm not going to argue with you (you seem to think everyone is wrong apart from you). Unfortunately you think you know it all because you have hours and thus the don't think rules apply to you. Question do you think you are better than a test pilot ? I know I'm not and never will be, that's why I follow the manual. I figure that in the 30-40 years the 73's been around they have figured out what is best.

Olster is absolutely correct deviate from the manuals at your peril! Boeing know what they are doing!

As for using the word knob.... its a term the us in the colonies use. Perhaps I should have said fool. Sorry if its lost on you northern hemisphere types.

I'm saddened that people could come on here and take what you said as gospel and apply it on the line with unfortunate/ unforeseen results. What they should do as Rubik and Olster pointed out is read the manuals to see the proper way to do it. ;)

[DC-ATE]

Rhodes13 -

The only problem with your "going by the book" thing is that in many cases when things really go wrong in a transport catagory aircraft (you ARE qualified in one, right?), you can take your book and throw it out the window!

One case comes to mind: AA 191. Another (can't recall the Flt No.) was our 747 out of PHNL when a cargo door blew out taking two engines with it.

Granted, you have to START with book procedures, but many times it just simply isn't in the book and that's where expeience comes in.

[Rhodes13]

DC-ate we are not talking about emergencies we are talking about NORMAL procedures. Thus we stick to the book because the aircraft has been certified to handle those conditions.

A cargo door coming off which isn't covered in the QRH and wasn't taken into account in certification then I agree do all you can then rely on experience!

And yes I do fly the 73 and what a lovely machine it is too.

[DC-ATE]

Well, this whole discussion centers around the incident in Denver, so I guess we'd better wait and see what the "Official" outcome is before persuing it further.

[rubik101]

To Rhodes, and many others who are of similar age and experience, I would say this. Some posters here will write utter twaddle, rumour, peurile tripe and complete trash and qualify it with the expression, IMO.
It doesn't make it any more reliable.
In fact, it generally means that they are of the school of thinking mentioned earlier, 'The Captain is always right.'
IMO, these posters are a danger and extremely detrimental to our 'profession'.
They should be ignored and consigned to the scrap heap from whence they came. After a few months on this forum you will learn which posters to ignore.
If you want to learn how to fly an aeroplane, read the manufacturers manuals, FCOMs, Training manuals and listen to the people who train you. They are doing their best to instill in our you all the experience and knowledge learned and earned over the past 100 years of aviation. Anyone who tells you that they know better is wrong, an idiot and dangerous.
Ignore them and their fantasies.

Probably better to keep individual IDs out of the firing line ? - JT

Follow the book and be safe.
Happy landings.
BTW, my 38 years flying and 27.000 hours mean little to the likes of such professional posters/bloggers on this forum.

[DC-ATE]

rubik101 -
"If you want to learn how to fly an aeroplane, read the manufacturers manuals, FCOMs, Training manuals and listen to the people who train you.....Anyone who tells you that they know better is wrong, an idiot and dangerous."


Poppy-cock!

I can relate a personal experience to you that had I not done it "my way", you would have read about a Boeing 737 "lost" in a "training accident". The "instructor" sat in the left seat dumb-founded while our airplane was in a deep stall, at night, in the overcast! Following the "book procedure" for stall recovery would have lead us right into the ground. Fortunately, after seeing that he knew nothing about what was happening, I took the necessary step toward a safe recovery, after which he had no comment.

This was NOT in a simulator either, but the actual aircraft.

There just happens to be times when some pilots have the knowledge that saves them, their airplane, and passengers (had they been aboard in this case). Is the Captain ALWAYS right? Of course not. Again, read between the lines of the post in question.

In the case I refer to above, the Captain was NOT right.

[CHfour]

Following the "book procedure" for stall recovery would have lead us right into the ground.


I think we deserve some more information about that event as it would obviously have major safety implications. I have only stalled the sim but found the stalling characteristics conventional apart from the larger than usual thrust pitch couple when TOGA thrust is applied. Presumably you reported it so I would like to know what Boeing had to say. Also, what on earth were you doing to get into a deep stall in those weather conditions?

[DC-ATE]

We were in the overcast at 15T (MSL), terrain ~ 7000 (Colorado Springs area). We DID have engine anit-ice on, but NOT wing. 737 has NO tail de-ice. Boeing said the tail didn't ice. How stupid can you be?!

Anyway, after doing the Clean, and Maneuver stall and revocery, the Landing configuation was next (gear down, 40 flap). I started to feel the elevator buffet before receiving the stick shaker, so called for the recovery procedure: T/O Power (excuse me...thrust), Flaps 15 (that procedure has changed a few times with regard to Flap setting). The "Captain Instructor" criticized me for not "taking it to the stick shaker." I told him I thought the "procedure" was to recognize an impending stall and recover. He said to take it to the stick shaker. Knowing I had sufficient altitude, I agreed and re-did the maneuver. As I started to feel the elevator buffet, I called that to his attention. You could see the stick moving back and forth! He said..."Take it to the Stick Shaker!" I might add that the buffett occured at a higher IAS than previous (more ICE!). Well, the stick shaker did come on and I called for the recovery procedure. He firewalled the throttles (excuse me...thrust levers) and we simply started to go DOWN with no increase in speed. I aksed him if he believed me now that we we starting to stall when I felt the buffett. He was kinda over there frozen not knowing just what was going on. Well, if you've flown the 737 (this was a -200 BTW), you'll know that with increased thrust the nose has a tendency to go up. I waited to see if this "Captain/Instructor" knew what to do. It was obvious he did not so I merely removed his hands from the throttles and pulled the throttles back about half way. The nose came down; speed picked up and I flew out of it. Simple.

I asked him after that if he though we might have some ice. My flying partner and I had both suggested wing anti-ice earlier, but he "knew better!" We flipped on the wing ice light and what do ya know? ICE. About 3 to 4 inches of the nice stuff! So, he calmly turns on the wing ice and we head for the barn. I said what about the tail, knowing there is NO tail anti-ice. He said not to worry because Boeing says the tail doesn't ice on this airplane.

Yes, this incedent was fully reported with NOTHING comming out of it. Wonder why?!?! We lost a 37 at MDW because of airfoil ice but it was never admitted to in the accident report. Why? Because Charlie Fox Dog (the Chicago Fire Department) said there was no ice visible when they got to the crash site. Well, .....the aircraft was on fire!

So.....the "BOOK" isn't always right. There's quite a few people no longer with us because some thought that. Sad.

Enough!

[framer]

I'll just bring this back to the topic cause I don't want it to get closed. Earlier I asked this question and I'm just wondering what some others think, a few more opinions maybe;
I wonder if having more aileron in than is required for the conditions results in more weight on the upwind wheels, which in turn causes a slight pull in that direction, which results in more rudder being required to track the centerline. Does that sound feasible?

Cheers.

[BOAC]

Framer - hopefully helping you back onto the centreline:)

IF you just stick on a fixed amount of aileron there is a good chance that your proposition will be true, but negligible. If you use aileron purely to control any wing-lift tendency then not, since the 'effective' weight on the wheel that side will be pretty much unchanged.

To diverge briefly from the topic (again), I have, I think, been fortunate all my flying career in being able to sense minute changes in acceleration and attitude (which has always made the artificial simulator 'motion' a problem for me) and as such have always been in the 'use aileron as and when needed' group (ie when I 'sense' the wing wanting to lift) during a x-wind takeoff in all the a/c I have flown. I also fully endorse the advice above to follow the manufacturers' guidelines rather than individual whims. In my time in aviation I have never seen a 'formal' suggestion to put on a fixed amount of aileron - it has, however, been 'suggested' by various training pilots, and I have watched many co-pilots (and a few Captains) do it. I suppose that for those of us who are 'blind' to the feel of an aircraft and cannot sense the lady wanting to do x. y or z, then some sort of robotic formula for setting into-wind aileron is better than rolling onto a wing-tip or engine pod.

It is always interesting to hear and think about others' techniques, but vital not to assume that because they appear to be 'experienced' they are the ones to follow.

[Rainboe]

I have, I think, been fortunate all my flying career in being able to sense minute changes in acceleration and attitude (which has always made the artificial simulator 'motion' a problem for me) and as such have always been in the 'use aileron as and when needed' group (ie when I 'sense' the wing wanting to lift) during a x-wind takeoff in all the a/c I have flown.

Even you with your 9000 posts can't 'sense' the wing wanting to lift! It already is lifting when your 'ever alert' razor senses have sensed it! That is why you should already be holding it down. But the point is, you are not holding it down- you are merely preventing it lifting by prebalancing the weight on the wheels. Get the point- you are NOT pressing the upwind wheel down. The standard former procedure beats the current advice from Boeing, probably because Boeing have totally 'dumbed down' their crosswind take-off advice because pilots who don't understand will possibly overdo it. Do it correctly and smoothly and it works like a dream....like it used to be done as normal procedure. Quite simple- 1 division per 5 kts across, hold it on steady. It used to work as standard procedure. Still does amazingly!

It's a shame that as I repeatedly stressed (IMO), this was merely a discussion item and an alternative suggestion to current advice. It was the old advice that works better for most people without superhuman, highly-honed and incredibly alert senses of.....something, like the previous former pilot. Fortunately, most of us normal plodders don't have such amazing senses- we do it on skills we pick up over the years, often from conversing with others who've been there and done it many times.

It was depressing to see the abuse it earned from yet another immature anti-podean (why do they talk to each other like that?) with a loud, expletive laden keyboard, like they all seem to have down there! Why was the Oz section closed a while ago? I have removed the postings. Better to keep it a secret (like the Boeing 'push')!

[BOAC]

Morning old chap- and a happy stress-free New Year to you.:D

May I point out that Even you with your 9000 posts can't 'sense' the wing wanting to lift! while you consider yourself an expert on everything else, you are not an expert on 'me'?

[Pugilistic Animus]

it appears we should get into a less contentious discussion about RTO's after V1 :ouch:


the Boeing push is a secret?


my stance most flight handbooks stipulate somewhere that " this manual is not intended to replace prerequisite flight skills"

spoilers do increase drag and can create directional control problems and you can 'feel an airplane'

there was a famous TP who did discuss crosswinds and I think you'll find most AFMs in line with what he wrote in a little book for all of us mere mortals:ooh:

oh and in my best professorial tone

"one should follow the guidance as specified in the airplane flight manual as it IS the MOST authoritative source----
there is a lotta faith in aviation never HOPE just faith

HOPE = Horrendous Outcomes Per Emotions [not my invention]

PA

[Checkboard]

One in service "test flight" that went badly was a 727 flown about 35 years ago by a fellow named Hoot Gibson. Hoot decided that he could deploy a litte flaps at cruise to achieve a higher altitude. The 27's did have locks on the leading edge devices, but guess what? Hoot just unlocked them! The result was much the same as the 37 real test flight. Hoot took a 30,000 foot spiral dive. Initial press reports extolled his hero flying skills, but when the facts were known he was unemployed.

This incident involved TWA Flight 841, a 727-100 on April 4 1979. The number seven leading edge slat extended in flight at altitude. The crew was accused of "cracking" the flaps - following an "urban myth" on increasing performance at altitude. This was denied by the entire crew, under oath. No crew could ever be found to have actually attempted the procedure, and when tested it was shown that performance immediately and markedly deteriorated (as you would expect, or Boeing would sell the aircraft with drooping flaps!).

While the slat is held shut by hydraulic pressure, and a mechanical lock, fracture of the actuating piston could cause a separation, however the suspect parts were never recovered. Boeing issued an AD strengthening the area in 1973, prior to this there were fifteen instances of uncommanded slat deployment. After the AD, and up to the accident there were a further two slat deployments, one from a failure of the slat actuator support fitting.

The CVR on the aircraft was found to be erased after the aircraft landed, however it was proven that this was impossible to achieve from the cockpit, as the landing gear squat switches were damaged in the event, and CVR erasure requires a safe gear indication (i.e. three greens, and the aircraft landed with three reds).

On balance, Captain Gibson most probably was a hero, and regardless it was his excellent flying skills which managed to save his aircraft and passengers.

[Rainboe]

Let's understand- the only reason you can 'sense' the wing wanting to lift is because it is actually in the process of lifting. It is actually coming up, and that is what you are feeling. Pray explain how you can 'sense' something that is not moving, unless you are hammered in which case you can definitely 'sense' your bed is swaying, and one side is definitely 'lifting'. This precedes emtying the contents of your stomach, which is what I feel when I read people bragging about their superhuman senses of.....sense or whatever they claim to have special powers of!

[Checkboard]

All this boils down to the FCTM, and the relevant quote is:
Limit control wheel input to that required to keep the wings level.

So, if you rotate in a crosswind, regardless of the techniques written here, if your wings remain level, you are following the FCTM. :ugh:

Advocates of presetting the aileron (and I am one) are not saying anything different - simply suggesting that using experience to anticipate a requirement is better than attempting to react to a requirement. :rolleyes:

[Checkboard]

If you want to learn how to fly an aeroplane, read the manufacturers manuals, FCOMs, Training manuals and listen to the people who train you. They are doing their best to instill in our you all the experience and knowledge learned and earned over the past 100 years of aviation. Anyone who tells you that they know better is wrong, an idiot and dangerous.
Ignore them and their fantasies.

... you may as well add:

cancell your PPRuNe membership, and never read TechLog
Never read industry magazines, or professional pamphlets from organisations such as BALPA
never read original NASA research papers
Absolutely never discuss flying with experienced pilots


...etc. :ugh:

I happen to believe that I don't know everything about my job. :bored:

I believe that to be true of my company's training department and Boeing's US lawyer-flitered lowest common denominator manuals as well. :suspect:

[Pugilistic Animus]

Advocates of presetting the aileron (and I am one) are not saying anything different - simply suggesting that using experience to anticipate a requirement is better than attempting to react to a requirement.exactly what Davies says something like it's better to stop a wing from lifting then to try and put it down then he says [basically] watch out with the spoilers and don't be too active on the wheel

Re: 'feel'
the dynamic pressure reactions can be felt whether you Preset or not

I have a sense that although there's not total agreement in this thread there is also not total disagreement either:cool:

now let us just hope the wings don't just fall off for no reason--:}


I hope the punters don't see my last sentence

[Rainboe]

About that 727 incident, I don't see why any explanation has to be made about the apparent erasure of the CVR. The obnly reason why such a 'spy in the sky' was permitted in our 'offices' was that it was a post-accident investigation device should there be no other way of establishing the events . If the pilots are there to give evidence, then there is no allowable function for the CVR to serve, so it must not be used. That was the basis we accepted the darn thing in the first place. Now it is apparently used as a prosecution device by lawyers against pilots. If anyone is alive to erase it, then it should be erased.

[Chesty Morgan]

I think what BOAC is describing is seat of the pants flying. Not the "flies by the seat of his pants" maverick plonker but simply feeling and reacting to movement of the aircraft or merely - flying an aeroplane.

If the wing begins to lift during the take off simply use enough aileron to stop it and keep the wings level. Just like you do when you're airborne.

My old man is a test pilot and his answer to this question when I asked him a long time ago was -

A wing is designed NOT to produce lift on the ground (which is why wake vortex, a product of lift, only starts at rotation). Therefore, by using spoilers and ailerons during the take off roll you are simply increasing drag and reducing your performance margins (balanced field!). Use enough, but no more, aileron to keep the wings level should it be required and fly the aeroplane down the runway. At rotation, fly the aeroplane off the runway maintaining wings level. Do not preset roll control.

It's not verbatim but you get the idea.

For those that preset the aileron. How do you know you are not using too much?

[Pugilistic Animus]

For those that preset the aileron. How do you know you are not using too much?I never did like talking angles[unless absolute limitations] I like to talk of pressure so not really a 'preset' more like a "pre -firm -controlled pressure- because you know" but that's hard to say and not very technical sounding

but as you accelerate before you increase your AOA at Vr you can nevertheless sense a need in the knuckles to either increase or decrease the as the dynamic pressure is affecting the flight controls via the artificial feed back system but I think most pilot are doing this either consciously or unconsciously --also at low speed the flight controls are not sensitive maybe it's all the Afro-Caribbean,Boricua and down south hybrid rhythm I got:}

PA

[Rainboe]

A wing is designed NOT to produce lift on the ground....but it does when the wing starts lifting above 80 kts!

I take it dad tested smaller types with big spoilers? Spoilers on airliners are not particularly effective, in fact sometimes I think they produce more vibration than drag. I refuse to accept there is ANY appreciable drag below 100kts, and very very minor drag up to 140kts. Remember at 1 division ONLY per 5 kt tailwind, you should never have more than 7 units aileron applied. Anybody who has more is not doing it right.

I positively maintain you cannot 'sense' a wing lifting. You can 'sense' the movement of a wing lifting, no matter how clever a pilot you think you are, in which case it is already physically in the process of lifting. Too late- it is already happening. So you are jockeying with aileron while you are desperately trying to jockey with the rudder to keep centreline? Why not make life easier for yourself? All I was trying to say was 'try it, and form your own opinion'. It's how it used to be done. It worked. Suddenly, because some truly astonishing operators now fly the thing, it is all dumbed down into lawyer-speak. That is how we used to do it, on 400 tonne 747s in hot and high operations on limiting runways. How is it suddenly so dangerous now on an overpowered 737?

[Rainboe]

you can nevertheless sense a need in the knuckles to either increase or decrease the as the dynamic pressure is affecting the flight controls via the artificial feed back system but I think most pilot are doing this either consciously or unconsciously --also at low speed the flight controls are not sensitive
Smoke and mirrors! Come on, seriously! You are feeling the wing actually lift. You are not 'sensing' some mysterious force. When you hold something that someone is pushing, (like furniture), you have no idea what force is on it and what it is experiencing until it suddenly jerks on you and moves! You cannot 'sense' any forces in it. Let's get rid of this 'sensing' hurdy-gurdy psychic nonsense! Until that wing starts lifting, you don't 'sense' bugger all!

And we are talking fully powered flight controls here. You are not feeling nowt naturally!

[Pugilistic Animus]

I don't even let the stinkin' wing twitch--and I'm an ok pilot nothing special in fact a bit lazy

And we are talking fully powered flight controls here.

yes as I said

either increase or decrease the as the dynamic pressure is affecting the flight controls via the artificial /feel feed back system

what's the ADC for?

yes I added the word 'feel' because I omitted it earlier

[BOAC]

RB - note what I said to sense minute changes in acceleration and attitude and I then later used 'sense'. You are just WRONG! Go on - make it a New Year's resolution...........

IncidentallyToo late- it is already happening. So you are jockeying with aileron while you are desperately trying to jockey with the rudder to keep centreline? - all I can say is you fly your way, if you must, and I fly mine. It has stood me in good stead with the many skills I have needed in my career for the various roles I have undertaken. You really must be absolutely exhausted after a x-wind take-off - and the co-pilot a bag of nerves? I guess you'd need a quick nap en-route to recover?

I do think Chesty summed it up wellbut simply feeling and reacting to movement of the aircraft or merely - flying an aeroplane. If the wing begins to lift during the take off simply use enough aileron to stop it and keep the wings level. Just like you do when you're airborne.Incidentally, Chesty, your dad was not completely right as quoted - many, many a/c have a positive angle of incidence on the wing during the ground roll and so produce both lift and vortices during the roll, they only become significant when the a/c rotates and the lift starts in earnest and the vortex is now not constrained by the ground. Indeed, some a/c (for reasons of geometry) have such a 'rigging angle' that they actually require no pitch change at 'rotate' to leave the ground. What he probably meant was that no wing is REQUIRED to produce lift on the ground until the moment of unstick.

[Chesty Morgan]

Too late- it is already happening. So you are jockeying with aileron while you are desperately trying to jockey with the rudder to keep centreline?

Which is why you stop it and is this not what we are doing when we are landing in a crosswind?

I refuse to accept there is ANY appreciable drag below 100kts, and very very minor drag up to 140kts

Well I obviously can't quantify it but it is there and it will affect the performance albeit by a small amount.

Why not make life easier for yourself?

Well, because the easy way isn't always the correct way. Or the safest.

I take it dad tested smaller types with big spoilers?

Generally yes but he has evaluated types from a Gazelle to an A320 and most things inbetween. He also flew the 737 for a number of years.

Edit: BOAC I stand corrected, my fault as it probably got lost in translation!:ok:

[CHfour]

DC-ATE

We were in the overcast at 15T (MSL), terrain ~ 7000 (Colorado Springs area). We DID have engine anit-ice on, but NOT wing. 737 has NO tail de-ice. Boeing said the tail didn't ice. How stupid can you be?!

Anyway, after doing the Clean, and Maneuver stall and revocery, the Landing configuation was next (gear down, 40 flap). I started to feel the elevator buffet before receiving the stick shaker, so called for the recovery procedure: T/O Power (excuse me...thrust), Flaps 15 (that procedure has changed a few times with regard to Flap setting). The "Captain Instructor" criticized me for not "taking it to the stick shaker." I told him I thought the "procedure" was to recognize an impending stall and recover. He said to take it to the stick shaker. Knowing I had sufficient altitude, I agreed and re-did the maneuver. As I started to feel the elevator buffet, I called that to his attention. You could see the stick moving back and forth! He said..."Take it to the Stick Shaker!" I might add that the buffett occured at a higher IAS than previous (more ICE!). Well, the stick shaker did come on and I called for the recovery procedure. He firewalled the throttles (excuse me...thrust levers) and we simply started to go DOWN with no increase in speed. I aksed him if he believed me now that we we starting to stall when I felt the buffett. He was kinda over there frozen not knowing just what was going on. Well, if you've flown the 737 (this was a -200 BTW), you'll know that with increased thrust the nose has a tendency to go up. I waited to see if this "Captain/Instructor" knew what to do. It was obvious he did not so I merely removed his hands from the throttles and pulled the throttles back about half way. The nose came down; speed picked up and I flew out of it. Simple.

I asked him after that if he though we might have some ice. My flying partner and I had both suggested wing anti-ice earlier, but he "knew better!" We flipped on the wing ice light and what do ya know? ICE. About 3 to 4 inches of the nice stuff! So, he calmly turns on the wing ice and we head for the barn. I said what about the tail, knowing there is NO tail anti-ice. He said not to worry because Boeing says the tail doesn't ice on this airplane.

Yes, this incedent was fully reported with NOTHING comming out of it. Wonder why?!?! We lost a 37 at MDW because of airfoil ice but it was never admitted to in the accident report. Why? Because Charlie Fox Dog (the Chicago Fire Department) said there was no ice visible when they got to the crash site. Well, .....the aircraft was on fire!

So.....the "BOOK" isn't always right. There's quite a few people no longer with us because some thought that. Sad.

Enough!
http://static.pprune.org/images/statusicon/user_offline.gif

I recently took part in a power off control check on a ferry flight. The elevator had been removed and re-fitted so the rigging had to be checked to make sure the aircraft would be controllable using manual reversion. We had to climb to FL350 and be VMC in daylight to carry out the check and we only carried out some straight and level stuff. I'm amazed that your company allowed stall training in IMC/Icing conditions. I can only speak for the 300 sim which does have a violent pitch up when TOGA is applied but we were instructed to apply full nose down elevator and apply nose down pitch trim until pitch control is recovered. You do see some extreme nose up attitudes but the thrust keeps you flying (provided you're not carrying ice?). I think Boeing suggest rolling the aircraft for extreme nose up attitudes to bring the nose back to the horizon but I would not fancy rolling a stalled aircraft myself. Thanks for taking the trouble to recall the story. I'm glad I don't fly for your company as I don't think I'm brave enough to get through your conversion training! I assume by the 200 reference that this happened some time ago?

[airfoilmod]

Right you are sir. Especially tandem gear A/C. BUFF. The B-52 does NOT
rotate, it levitates. suggestion: Rainboe nor you are wrong. Words have shades of meaning, and can trap professionals and others in meaningless disagreements. Richard Bach may fly differently (sic) than de Havilland or John Boyd, but Physics is physics and in my humble (!) opinion is not subject to nuance. Interpretation? Certainly.

[Pugilistic Animus]

AFM,
glad to see you back posting --I like your viewpoint you are very balanced---:ok:


PA

[Graybeard]

"Spoilers on airliners are not particularly effective, in fact sometimes I think they produce more vibration than drag. I refuse to accept there is ANY appreciable drag below 100kts, and very very minor drag up to 140kts."

Guess you're unfamiliar with the DC-9. . AeroMebbe crashed one after emergency descent, as it wouldn't fly with the spoilers still up. I was once SLF just aft of the wing on an MD-80 that was trying to hold at 6K feet after descent toward KLAX. We were getting pre-stall shake until he retracted spoilers. Yes, I've been on big airplane test flights, and know stalls. Ever watch the Horizontal stab of a DC-10 during stall? One of the techs said, "Oooh! Wish I'd never seen that."

In all this discussion, I have seen no mention of fuselage blanking lift on the downwind wing.

GB

[Rainboe]

We're talking about spoilers cracked open a small proportion of travel, on one wing, at up to and below 140 kts, rather than full spoiler operation on both sides at 150kts plus. A good rainfall on the fuselage and wings will probably provide more drag!

I have, I think, been fortunate all my flying career in being able to sense minute changes in acceleration and attitude
I was never blessed with razor sharp super-senses and other superpowers! I sure wish I was gifted with some of BOAC's superpowers! I'd settle for the X-ray vision- must have been well fun with the cabin crew! I have to do it the hard way. Plod along....but I enjoy it, even if i only do it by the numbers. Haven't broken anybody yet......except the baggage cart driver at Washington. That was her fault though.

[Pugilistic Animus]

Everyone on pprune is either 'doing something right' or just damn lucky' how do I know? because they're still here to post;)

I'm NOT proselytizing but I think the following passages from Ecclesiastes is appropriate

1:3 What profit hath a man of all his labour which he taketh under the sun?
1:4 One generation passeth away, and another generation cometh: but the earth abideth for ever.
1:5 The sun also ariseth, and the sun goeth down, and hasteth to his place where he arose.
1:6 The wind goeth toward the south, and turneth about unto the north; it whirleth about continually, and the wind returneth again according to his circuits.
1:7 All the rivers run into the sea; yet the sea is not full; unto the place from whence the rivers come, thither they return again.
1: 8 All things are full of labour; man cannot utter it: the eye is not satisfied with seeing, nor the ear filled with hearing.
1:9 The thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun.
1:10 Is there any thing whereof it may be said, See, this is new? it hath been already of old time, which was before us.
1:11 There is no remembrance of former things; neither shall there be any remembrance of things that are to come with those that shall come after.

[Rainboe]

1.12 Yo bro', give a man a fish and he is fed for one day. Teach him how to fish and he can drink beer all day.

Wossit got to do with Xwind take-off, PA?

[Pugilistic Animus]

Wossit got to do with Xwind take-off, PA?

all of flying life etc.


by PA: exactly what Davies says something like it's better to stop a wing from lifting then to try and put it down then he says watch out with the spoilers and don't be too active on the wheel


by Check Board: Advocates of presetting the aileron (and I am one) are not saying anything different - simply suggesting that using experience to anticipate a requirement is better than attempting to react to a requirement.

by Rainboe We're talking about spoilers cracked open a small proportion of travel, on one wing, at up to and below 140 kts, rather than full spoiler operation on both sides at 150kts plus. A good rainfall on the fuselage and wings will probably provide more drag!

by Airfoilmod Each may fly differently (sic) than de Havilland or John Boyd, but Physics is physics and in my humble (!) opinion is not subject to nuance. Interpretation? Certainly.




[B]1: 8 All things are full of labour; man cannot utter it: the eye is not satisfied with seeing, nor the ear filled with hearing.
1:9 The thing that hath been, it is that which shall be; and that which is done is that which shall be done: and there is no new thing under the sun.
1:10 Is there any thing whereof it may be said, See, this is new? it hath been already of old time, which was before us.
1:11 There is no remembrance of former things; neither shall there be any remembrance of things that are to come with those that shall come after.

[airfoilmod]

Not Of Thread but of Pride, which goeth before the excursion into the weeds of thy noble air machine, blocking her true relationship with the wind that carries her aloft.

Humility is the understanding of one's true self. Those who aspire to wisdom generally make the least noise.

Howdy PA, and an elegant perspective of flight you offer. AF

[DC-ATE]

CHfour -
"I'm glad I don't fly for your company as I don't think I'm brave enough to get through your conversion training! I assume by the 200 reference that this happened some time ago?"

You have to realize that took place in 1969! There is no transition training in the actual aircraft any more. Hasn't been for many, many years.

Anything further on this, I suggest a new thread as we're way off topic.