Go around flaps

[globaltrainer]

Hi,

One of my customer made a very relevant remark.Raising the flaps prior to raising the gear on a low energy go around would lead the aircraft to sink. However, our procedure is to call: GO AROUND, CHECK THRUST, THRUST SET, FLAPS 6, POSITIVE RATE, GEAR UP.....

Now I'm sure the aircraft manifacturer figured the best procedure but I"d like to be able to better explain scientifically why it is better to raise the flaps first rather that raising the gear. Boeing & Embraer do the same, to name a few.

Would your take?

[Cough]

Raising the gear will extend the gear doors increasing drag. Raising the flaps from fully extended by one stage will normally reduce quite a bit of drag, with the most minor effect on lift...

Also, if you lift the gear first then on some aircraft you'll get a configuration warning.

[Sidestick_n_Rudder]

Higher flap settings produce more drag increase than lift increase.

On go-around reducing flaps from full to an intermediate config will greatly reduce drag without much lift penalty - thus increasing climb performance.

At the same time, approach speed should be sufficient to fly with reduced flap setting.

If you end up with speed waay below Vref, it’s prudent to keep landing config until speed above Vref. At the same time, you should avoid getting into this state in the first place...

[globaltrainer]

thanks to you both!

[vilas]

Gear is the only part of the aircraft designed to take impact load. It will withstand even hard impact but fuselage won't survive. If gear was not retracted prematuerly Dubai crash aircraft may not have broken up. Retracting landing flap causes small loss of lift but retracting gear will add drag till it is retracted.

[oxenos]

If on a Cat III approach,a very late go-around becomes necessary, the aircraft will continue to descend briefly before climb is established. The wheels may well touch the runway at this point. If the gear is retracted before a positive rate of climb is indicated, there could be be a very expensive noise.Try it in the sim next time.

[pattern_is_full]

Additionally (nothing wrong with the posts so far):

With low-engine-location craft such as the 737, TOGA thrust with approach flaps still deployed can lead to strong pitch-ups, with possible stalls and/or other loss of control.

Such as this recent event still being discussed, and a couple of others in Russia that were fatal.

http://www.pprune.org/rumours-news/601048-13-10-17-ut588-krr-vko.html

Thus getting the flaps up a bit is a higher safety priority than the gear.

[jurassicjockey]

To add to all the other comments, if the plane is going to sink a bit with flap retraction, better that it should happen before the positive rate call, and before the gear is raised

[B2N2]

I hate to be pedantic but you’ve already given the answer in your question

FLAPS 6, POSITIVE RATE, GEAR UP.....

You don’t touch the gear unless you’re climbing at a safe speed.

[FE Hoppy]

The height loss during a go around is a rather important figure which is well tested and documented by the manufacturer. It's in their interest to obtain the lowest value whilst describing a procedure that the average crew can accomplish.

As for retracting the gear in a low energy state close to the ground. LOL!!!

[physicus]

yeah, last time someone did that, the resulting mayhem left my suitcase sitting at DXB on the tarmac in 40deg heat with vacuum sealed, iced, fresh flathead fillets for 4 days. Neither the vacuum seal, nor the freshness prevailed.

[GlenQuagmire]

When you make the Go Around Check Thrust Flap 6 call you are also pitching for the go around attitude. The config change from flap 30 to flap 6 only causes a sink if you don't change the attitude/AOA at the same time. Checking that the thrust is set makes sure you have enough energy going into the system such that the pitch change means you don't lose speed. Once the aircraft is established in the go around attitude you don't need quite as much lift anyway which is part of the reason why the small reduction of lift from retracting the flap from 30 to 6 shouldn't cause a significant sink. That would only happen if you don't change the attitude..

well thats what I think.. could be wrong.. who knows, its all witchcraft

[Chesty Morgan]

who knows, its all witchcraft

Exactly!
LIFT DEMONS (http://messybeast.com/dragonqueen/liftdemon.htm)

[Capt Pit Bull]

Plus of course you must meet the minimum speed requirement for the flap retraction schedule for the aircraft in question.

If you are low energy you may not be able to take even the last stage back in.

Ultimately if you are very low energy then ground contact may be inevitable.

At the risk of pointing out the obvious, this is why we don't fly dangerously slow in the approach..... because it's dangerous!