Will you retract slats/flaps in windshear?
 

Recently, I had a sim session and handled a windshear exercise immediately after T/O. Airspeed went way above S momentarily while I was maintaining FD.

After completion of the session, Instruction debriefed that I should have retracted the slats/flaps to prevent damage to them.

In my opinion, FD guidance will adjust accordingly to prevent such speed excursion, so I shouldn't retract the slats/flaps and stick to the written procedure.

We entered into windshear immediately after take-off - red WINDSHEAR warning with audio.

Speed excursion was momentary. Speed decreased below S after the excursion. So we were NOT out of windshear, the time when Instructor wished I should have retracted the S/F

I wish to know if you had similar experiences and your useful opinion

No, not until clear of shear and at a safe altitude

Good idea. Ask Bloggs what he would suggest you do if, after having rectracted said flaps/slats (and probably not damaging them) you then suddenly fly into the opposite tailwind shear. Extend them? :rolleyes:

Maintain configuration.

IFLY_INDIGO
There is dilemma here because you mustn't change configuration that is definite but you should not damage your flaps. The correct and safe way of saving the flaps is to fly above the flight directors to convert speed into height and when the speed trend reverses again fly the FDs. This might get you out of wind shear itself. This is airbus recommended procedure.

I suggest you might like to ask the Instructor to show you the data on the aircraft’s windshear response that he/she has produced, which overrides that produced by the aircraft manufacturer who designed it (aided by massively powerful computers and very clever people) the aerodynamicists who wind-tunnel tested it, and the Regulatory Authorities who certified it.

He or she must be one very wise person if they are able to debunk the universal industry-standard procedure – to NOT reconfigure in windshear. Very impressive …. :ugh:

Will you retract slats/flaps in windshear?
 

FD will not prevent flap speed exceedance

Isn't the speed increase a sign that the wind shear is over? Ok, there may be a second speed loss etc. but at some point one finally has to resume normal ops...

I would also be careful about pitching up above the FD. IIRC SRS w/s recovery mode limits the pitch to 22 degrees (or thereabouts) pitching significantly higher than that could put the a/c in an undesired energy state...

Also, a minor flap over speed is no drama - wings won't fall off...

at first blush I thought you did the correct thing, then I realized if you had gotten your speed and altitude and had escaped the windshear, then you should start to clean up.

so, what altitude and what airspeed were you ?

and when did you start cleaning up?

For example, if you were over 1000' agl and in a normal climb profile, maybe you should have started the flaps up.

So, we really need quite a bit more info.

We had a similar scenario last year followed by some casual opinions about retracting flaps during a huge speed excursion.

My attitude towards that is they make flap components every day. Microbursts less than once a career.

F and S speeds are weight dependant. Placard speeds are not, but even there some statistical margin exists.

Potential flap damage due to slight overspeed is minimal compared to fuselage contact with ground due to loss of control.

This is your captain Obvious speaking: universal procedure is to maintain config until absolutely sure you have escaped windshear.

I find option "Find more posts by" quite useful.

Clandestino

Y-e-e-s, I see exactly what you mean ....

Rapid speed increase is not a sign of being out of shear only sign of wind direction/speed change. That's what windshear is And there is no guarantee it will be little overspeed. It happens in SIM and what I stated is how Airbus teaches.

That is a case of negative training!!!

The procedure is very specific. Passing S speed is not a command for retraction in a windshear. Exceeding VFE, that is a different story.

The procedure says, DO NOT CHANGE CONFIGURATION (SLATS/FLAPS, GEAR) UNTIL OUT OF SHEAR

Were you out of shear? Oh, and also you don't have to retract flaps/slats when passing S speed in case of turbulence, you can delay that 20 kt or VFE -5 kt, If I recall correctly. That situation was, at least, turbulence.

and at the end: RECOVER SMOOTHLY TO NORMAL CLIMB OUT OF SHEAR

Stick to the memory items until out of shear. Speed increasing very fast towards VFE, with imminent penetration in overspeed, then you can continue with the "normal" climb: THR CLB, retract slats/flaps (and don't forget L/G if that is the case!).

Some say retarding thrust is the last, but it is not written anywhere. The primary thing here (after avoiding crashing into terrain) is not to exceed a limitation.

Dear-oh-dear...

The question is whether you are out of wind shear. If not leave that LVR CLB flashing, flaps, gear everything as it is. You can control speed by pitching just above the FD. You should not bring the thrust levers back unless out of it. Another thing is what was the acceleration altitude. If it was low as 800ft. then in any case you will have to ignore the FD once SRS changes to CLB and pitch up to keep climbing because FDs will come down to give you acceleration .

A subtle note to your training provider regarding the accuracy of the mentioned trainer's point of view would be a suggestion.
It:

1. Clears up the answer in their response
2. Highlights the accuracy of the trainer's knowledge
3. Prevents further anomalies to be instructed on this subject to other crew

The industry standard, based on extensive research and manufacturers input, is to retain the existing configuration; AC 00-54.

If there is a guidance system, AP or FD, then use it. The manufacturer’s certification tests should have considered speed excursions during certification, i.e. probability of flap exceedance vs damage, or likelihood of encountering such a gross speed deviation vs the survivability in such a severe encounter.

In this (Windshear-Encounter) the crew followed the required recovery procedure (no computed guidance) and survived. Also, note that the FDR analysis showed that this actual encounter was very similar to the FAA simulated training model which was based on the infamous DFW accident.

Also see https://www.scribd.com/doc/232325774/Windshear

Following the FD "in windshear" can mean a number of things. Was the Windshear encounter determined by the Windshear Warning (in which case FD gives appropriate guidance)? Or "pilot assessed", when you just get normal SRS commands?

You then have the Aa issue, where the FD might change to CLB, but if still in windshear, it might be inappropriate to follow it.

Bottom line though is if you have not yet clearly communicated between the crew that you are clear of the shear, and adopted an acceleration profile, then you maintain config from my training.

clarification for better response:
We entered into windshear immediately after take-off - red WINDSHEAR warning with audio.
Speed excursion was momentary. Speed decreased below S after the excursion. So we were NOT out of windshear when instructor wished I should have retracted the S/F

Similar to what was mentioned before, stick shaker just after takeoff because you got an airspeed loss after previously having a gain and retracting flaps is not a nice idea at all. Would much rather exceed flap limits and deal with whatever that might bring (IMO probably nothing unless something really weird is happening).

As an anecdote, a company I previously worked for (flying something single pilot and lighter) had a pilot who for over a year didn't know what the limiting speeds for the first couple of stages of flap, and exceeded them probably numerous times a week until he finally did the same thing on an OPC.

Did your debrief discussion include a review of the written procedure? What does it say? Was his assertion in line with, or contrary to, the written procedure?

In general, as others have said, the windshear escape maneuver is done with NO configuration change other than retracting speedbrakes, if extended. There is likely NO note that says to retract flaps if the airspeed momentarily exceeds the current flap speed during the shear. One reason is that the airspeed is likely to reduce to BELOW the safety speed for retracted flaps, BEFORE they are even fully retracted!

IF the instructor's assertion was contrary to the written procedure, you should make a written report to the training center for which he works, reporting his contradiction of written procedure.

While the windshear is occurring, flap damage is NOT your primary concern -- staying out of the dirt is! Don't make up procedures, or allow bad instructors to lead you into made-up procedures! Does your procedure tell you to follow the FD, or to pitch to a certain limit (e.g., pitch angle or stick shaker)?

OK465: ESPECIALLY immediately after takeoff, retracting flaps is NOT a good idea. The momentary speed excursion is VERY likely to reverse; and if the flaps are retracted, stall is MUCH more likely. While there MIGHT be a valid discussion in some airplanes regarding flap position vs climb performance (e.g., FLAPS 10 vs FLAPS 20 in the 747), there is a MUCH higher likelihood of a WRONG change being made in the heat of the moment.

Flap exceedence is an easier write-up than an obituary. Your instructor sounds like he has too much time in the cubicles thinking of minutiae.

Exactly. You don't care about your flap limitations when in a windshear situation close to the ground. You try to prevent the crash and worry about flap speed exceedences later which will most likely have not caused any damage anyways.

Once safely clear of the windshear worry about configuration.

Also remember that S speed is not the only condition for retracting. The trend arrow should be showing acceleration and if you are in turbulence, you may delay retraction 20 kt or VFE-5 kt. If trend is erratic, you are in turbulence and speed may well go below S again.

If on top of that you have a RWS going on, man… The procedure is crystal clear.

You had some negative training that day. It happens from time to time.

Windshear, fly escape maneuver, maintain configuration, end of discussion.

True, but currently the only technology available to identify such cases is hindsight. Might change with lidars coupled to performance computers but the time passing between Ueberlingen and TCAS 7.1 gives me no reason to be optimistic.

I know nothing about Airbus's but purely from an airmanship point of view Id suggest that your instructor/checker doesn't know what he's talking about. Frightening actually.

Boeing procedures is to not change configuration and I belive that is mainly due to the fact that things moving in an airstream produce more drag than stationary things.

If flown properly and the thrust managed you should not exceed any limits however it's not deadly if you do, retracting the high lift devices against the manufacturers recommendation based on a fear of breaking them is ludicrous. Let me ask you this, how long do they take to retract, do you have any hope that they would have fully retracted before the exceedance occurs.

Our procedures require f5 takeoffs and to get the LE devices in would require the selection of flaps up, not sensible considering large speed variations and the time it would take.

Stator vane

With 26 years in civil aviation, may I wholeheartedly endorse your comments, though my slightly more graphic remarks yesterday evening obviously offended the mod(s) and were excised!!!

There are too many 'trainers' out there who vary from being an irritation during OPC/LPC checks to those who are positively dangerous, leaving ordinary capable line dogs demoralized and sometimes confused on points of technique or procedure.

How often have I heard the question " WHO told you THAT?" etc etc

And some in these fora have the effrontery to criticise other cultures' training regimes whils the most appalling rubbish gets pushed in EASA supervised & approved airlines! :ugh:

IFLY INDIGO...CONGRATULATIONS! You must have aced the totally unexpected and extremely worst case windshear scenario that your instructor was utterly gobsmacked that he only wanted to bring you a few notches down.

There are many Alteon instructors like that. If you do so well in a check item, they will come up with very devious " shock and awe " failures to make you sweat and puff. Just KNOW that you had the best of him/her, come away with a glow and a smile!:ok:

Use SPD brakes

Though I'm not a pilot, to me changing aircraft configuration in the middle of a windshear defies common sense.

If it were me, I think I'd respond to the instructor something to the effect of "I've always been taught to not change configuration during a windshear upset, could you please provide a reference for this 'new to me' procedure so I can investigate further?"

S speed is not a limitation, it is the lowest speed at which you can select flap 0. Many have already posted the obvious, that changing configuration is a dangerous, ridiculous idea.

Some things I have done with sudden speed increases associated with windshear:

1. Convert the momentary speed increase into altitude, i.e. pull up above the FD demand. Be careful not to overdo it though.
2. Momentarity reduce the thrust a little, to approx 65-75% N1, if you're aboslutely sure that the speed trend is positive and you are going to overspeed. You can always put the thrust back on quickly, something you can't do if you start retracting slats. Obviously don't go anywhere near idle as it would take longer to get max thrust back.

Finally, as has already been mentioned a 10-15kts overspeed won't break the wings off whereas impacting the ground will.

I would go for the 'speed for height' exchange as well. It's all about energy management and survival. Do you consider raising the gear as a change of configuration? I would allow that as the increase in performance might just save the day. Some say that ground impact would be softened with gear down, but with it retracted it might not happen at all. You choose.

Windshear recovery is solely about Energy Management. The Windshear has the potential to render your current PE + KE inadequate for flight i.e. KE to keep flying leaves PE as underground :{

The way I see it, your aims:

1. ADD as much Energy as possible = Full Power, no speedbrake
2. OPTIMISE your KE v PE balance, essentially means keep KE close to, but above minimum speed which equates to max PE (Height) - negative PE is not good for your health

Refinements such as gear up, more flap might, with hindsight, save the day, but you need a simple reliable drill.

If following the FD leads you to have excess speed, either:

1. The FD is not giving you the correct Windshear profile = ignore/deselect it, pull nose higher for PE v KE
2. The Windshear is significant, and the "gain" you are seeing may well be reversed - it is not a "good" sign

RAT 5 - retracting the gear will open the gear doors and add a whole lot of extra drag just when you don't need it. We are told to leave it well alone and I agree.

windshear escape must be predicated on KISS

(kiss: keep it simple stupid).

IF you want to get fancy and go against KISS, you could turn off the bleeds and generators and get more thrust from the engine. Not many of us could do that while trying to fly the plane, so KISS.

An overspeed, but otherwise successful windshear escape maneuver, is a success. But certainly, once clear of windshear, clean up and throttle back.

@Zippy, that depends on type. On the 737 the gear doors are already open anyway.

But, as pointed out above, it is a KISS example across types and therefore it probably is better to keep to the basics and simply fly out of it before worrying about configuration.