flaps in turns

[WrongWayCorrigan]

Any one know the wrongs and rights of lowering flap in a turn, especially on making the base turn?

Regs, Jim

[TheOddOne]

I was once rapped over the knuckles by a very experienced Flight Test Examiner, one Eric Thurston, for lowering flap during a turn in a C172.

He said that you should always make changes to flap settings with wings level so that if one flap lowered and not the other, you'd be made instantly aware by the uncommanded roll and hopefully address the situation. If you're in a turn (especially base/final as we were) you'd never be able to sort it out. That's also a good reason for lowering and raising flap in stages, rather than all at once. Of course, NEVER just flick the switch and rely on the next detent to hold it, positively check the switch position.

That was 15 years ago and I've always followed his advice since.

Although the PA28 system seems intrinsically safer, I still follow the 'wings level' routine for any flap change with this type, too.

Although I only flew with Eric on that one test (he passed me, for some strange reason!) I do recall a number of aspects of the flight that have stayed with my flying. He struck me as a remarkable bloke. I don't know if he's still around, but aviation certainly benefited from his work!

We had an accident with our Rallye when someone allowed the switch to go all the way through, but that's another story!


Cheers,
The Odd One

[Milt]

Know your own limitations and those of your aircraft.

Flaps increase your margin over a stall but may also make the stall more difficult to handle.

The Mustang fighter has strengthened combat flaps to give it an enhanced turning capability in dogfighting.

Some limitations become rediculous as the following story shows

Only two training aircraft were serviceable at Point Cook Flying School in January 1916. They were the English built Bristol BE2, a two-seater biplane with warping wings and an 89hp V8 air-cooled motor in each. Del’s reputation and qualifications as a pilot being well-known, he was ordered by Captain Harrison on the day after he arrived at Point Cook, to make a test flight, and to demonstrate his flying ability in one of the BE2a machines. He obeyed with enthusiasm. After carefully examining the aircraft and testing its controls, followed by several “rolls” on the ground and short straight flights across the aerodrome, he proceeded to take off and climb in a spiral, with banking turns, as he had done so often in his Caudron.

He was impressed with the performance of the BE2a with its higher engine power than his Caudron. It climbed much faster and turned more quickly, however, when he landed he was ordered before Captain Harrison who reprimanded him for what he considered to be “dangerous flying”. and ordered him in future not to make climbing turns.

This was a difficult order for Del, as a competent pilot, to obey. Captain Harrisons’s idea was that his pupils should climb only on a straight course, then level the machine before making a full turn, then climb again, in a series of zigzags. That was an elementary procedure for novice pupil pilots but ridiculously cautious for a pilot who was qualified and had full control of his aircraft. Del could not avoid continuing to incur Captain Harrisons’s displeasure and delighted in doing so.

[Rosanna]

I always teach to extend flaps with leveled wings. But it's more for a pratical reason... in turn, especially in base turn, students with a few hours are concentrated to mantain attitude, bank and speed and it's difficult for them to do other things like extract flaps or reduce throttle.

Ciao!!!

Rosanna

[homeguard]

There has been a long discussion already on the factors regarding flaps and the stall.

The stall speed is increased during a turn and the result of stalling with flap can be sudden and surprising but made much worse when with an angle of bank!

Turning at say 500' above the threshold, a height which may be much lower than that AGL, at the point the turn is made onto final, is not wise.

[aces low]

Whatever your views or prejudices regarding flap selection when wings are not level, it is still worth teaching students to be able to select flap while turning. It can help keep the circuit tight (yes, that old chestnut) and may even be essential at some fields. If you are doing a military type circuit (ovals not squares) it may be a local requirement to take flap while turning base.

May as well teach the students to be competent at it, even if it is not something you would do yourself.
I

[Tinstaafl]

20 odd years ago when I was learning to fly there was never a suggestion of there being a problem selecting flap during turns. It was a quite normal thing to do. The only difference to extending them in a turn compared to S&L or a Clb, or a Desc. was to ensure the 'g' limit was less than 2 (that being the C152's & C172's flapped 'g' limit'). Of course that limitation for use applies equally to all other 'g' loaded circumstances so not particularly unique to turning.

If you want them, use them. As long as any limitations are observed of course.

[buzzc152]

Off topic, but for the benefit of TheOddone : Yes, Eric is still around and teaching IR at Stapleford..... though only in the sim.

[FlyingForFun]

I guess there isn't going to be any agreement on this one. So, for what it's worth, here's what I do and what I teach.

Generally, I teach students to turn base, and then slow down and lower flap as soon as the base turn is complete. For many students, I leave it there.

But for the more competent students, I go one stage further once they've got the hang of this, and teach them to take the wind into account. So if there is a cross-wind from the dead side, this will hold you back on base leg, so you can wait a little longer before selecting flap. On the other hand, if the cross-wind is from the live side it will create a tail-wind on base leg and speed you up, so you need to get everything set up a little bit sooner. This may well mean selecting flaps during the base turn. I have no problem with this - it's what I do myself, and if my students make an informed decision to do the same that's fine by me.

I have no doubt that my opinion will change the first time I encounter asymmetric flaps, though! :eek:

FFF
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[Tinstaafl]

I taught to reduce power to ~1500 rpm & turn base at 45 deg from the runway (not 'from the aircraft' due to drift allowances). Hold altitude during the turn, selecting 1st stage flap once the IAS is permanently under the limit speed. As IAS nears the approach speed lower the nose to maintain the speed.

[Astronomy Dominie]

I'm happy lowering them anytime, anyplace, anywhere...

Flap assymmetry is much more a 'big aircraft' problem than one for light aircraft. Most light aircraft have a torque tube which ensures that flap travel must be symmetrical (unless something truly disastrous happens, in which case the problems will be much more serious than one flap slightly lower than the other!).

One other reason: carrying out a forced landing, it may be necessary to use a combination of configuration changes and S-turns, possibly on very short final approach, and if you haven't taught your stude that it's OK to do so, then you introduce a new hazard... :ok:

[BigEndBob]

Its more of a Cessna 150/152 problem where one flap is driven by the motor and the other by cable, if it snags you get one going down and not the other and unexpected roll.


Did have a situation where flap was raised to 1st stage by student on touch and go resulting in very poor rate of climb,...the flap lever was at 1st stage but flap stuck at 3rd!

[Lou Scannon]

When I went through flying training in the early sixties, I was told that not lowering flaps in a turn started with the Wellington. It would seem that this aircraft tended towards asymmetrical flap-....like one might move but not both!

Thus it was thought that lowering during a turn might initially obscure a dangerous failure. Subsequent designs usually had both flap asymmetry detection and lock-outs should it start.

The same was said about never turning towards the dead engine but again, this was before the knowledge about safety speed and crit speed had been hard earned.

I have to say that since then I have raised and lowered flap (or called for the flaps to be raised or lowered) on many types without concern and even turned towards the dead engine when circumstances required.

...but then I read the bit about the Cessna flaps!

[wheels up]

I figure in an assymetric flap situation you're going to know about whether in a bank or not!

[kookabat]

Flap lever on a 152 has always bothered me... a number of times I've had to 'jiggle' the lever around a bit to get some sort of movement out of the flaps - and the indents are invariably worn out so there's no physical stop between stages...

[BigEndBob]

Or the lever is bent to the right by pilots constantly pushing the lever too far right when lowering the flaps.

Also jiggle the flaps on preflight, make sure all those rollers rattle, if not one could wear out the flap track or seize, jamming the flaps.